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• Lockless queue implementation ends up having a loop under stress

  - by Fozi

  I have lockless queues written in C in form of a linked list that contains requests from several threads posted to and handled in a single thread. After a few hours of stress I end up having the last request's next pointer pointing to itself, which creates an endless loop and locks up the handling thread. The application runs (and fails) on both Linux and Windows. I'm debugging on Windows, where my COMPARE_EXCHANGE_PTR maps to InterlockedCompareExchangePointer. This is the code that pushes a request to the head of the list, and is called from several threads: void push_request(struct request * volatile * root, struct request * request) { assert(request); do { request->next = *root; } while(COMPARE_EXCHANGE_PTR(root, request, request->next) != request->next); } This is the code that gets a request from the end of the list, and is only called by a single thread that is handling them: struct request * pop_request(struct request * volatile * root) { struct request * volatile * p; struct request * request; do { p = root; while(*p && (*p)->next) p = &(*p)->next; // <- loops here request = *p; } while(COMPARE_EXCHANGE_PTR(p, NULL, request) != request); assert(request->next == NULL); return request; } Note that I'm not using a tail pointer because I wanted to avoid the complication of having to deal with the tail pointer in push_request. However I suspect that the problem might be in the way I find the end of the list. There are several places that push a request into the queue, but they all look generaly like this: // device->requests is defined as struct request * volatile requests; struct request * request = malloc(sizeof(struct request)); if(request) { // fill out request fields push_request(&device->requests, request); sem_post(device->request_sem); } The code that handles the request is doing more than that, but in essence does this in a loop: if(sem_wait_timeout(device->request_sem, timeout) == sem_success) { struct request * request = pop_request(&device->requests); // handle request free(request); } I also just added a function that is checking the list for duplicates before and after each operation, but I'm afraid that this check will change the timing so that I will never encounter the point where it fails. (I'm waiting for it to break as I'm writing this.) When I break the hanging program the handler thread loops in pop_request at the marked position. I have a valid list of one or more requests and the last one's next pointer points to itself. The request queues are usually short, I've never seen more then 10, and only 1 and 3 the two times I could take a look at this failure in the debugger. I thought this through as much as I could and I came to the conclusion that I should never be able to end up with a loop in my list unless I push the same request twice. I'm quite sure that this never happens. I'm also fairly sure (although not completely) that it's not the ABA problem. I know that I might pop more than one request at the same time, but I believe this is irrelevant here, and I've never seen it happening. (I'll fix this as well) I thought long and hard about how I can break my function, but I don't see a way to end up with a loop. So the question is: Can someone see a way how this can break? Can someone prove that this can not? Eventually I will solve this (maybe by using a tail pointer or some other solution - locking would be a problem because the threads that post should not be locked, I do have a RW lock at hand though) but I would like to make sure that changing the list actually solves my problem (as opposed to makes it just less likely because of different timing).

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• Load and Web Performance Testing using Visual Studio Ultimate 2010-Part 3

  - by Tarun Arora

  Welcome back once again, in Part 1 of Load and Web Performance Testing using Visual Studio 2010 I talked about why Performance Testing the application is important, the test tools available in Visual Studio Ultimate 2010 and various test rig topologies, in Part 2 of Load and Web Performance Testing using Visual Studio 2010 I discussed the details of web performance & load tests as well as why it’s important to follow a goal based pattern while performance testing your application. In part 3 I’ll be discussing Test Result Analysis, Test Result Drill through, Test Report Generation, Test Run Comparison, Asp.net Profiler and some closing thoughts. Test Results – I see some creepy worms! In Part 2 we put together a web performance test and a load test, lets run the test to see load test to see how the Web site responds to the load simulation. While the load test is running you will be able to see close to real time analysis in the Load Test Analyser window. You can use the Load Test Analyser to conduct load test analysis in three ways: Monitor a running load test - A condensed set of the performance counter data is maintained in memory. To prevent the results memory requirements from growing unbounded, up to 200 samples for each performance counter are maintained. This includes 100 evenly spaced samples that span the current elapsed time of the run and the most recent 100 samples.         After the load test run is completed - The test controller spools all collected performance counter data to a database while the test is running. Additional data, such as timing details and error details, is loaded into the database when the test completes. The performance data for a completed test is loaded from the database and analysed by the Load Test Analyser. Below you can see a screen shot of the summary view, this provides key results in a format that is compact and easy to read. You can also print the load test summary, this is generated after the test has completed or been stopped.         Analyse the load test results of a previously run load test – We’ll see this in the section where i discuss comparison between two test runs. The performance counters can be plotted on the graphs. You also have the option to highlight a selected part of the test and view details, drill down to the user activity chart where you can hover over to see more details of the test run.   Generate Report => Test Run Comparisons The level of reports you can generate using the Load Test Analyser is astonishing. You have the option to create excel reports and conduct side by side analysis of two test results or to track trend analysis. The tools also allows you to export the graph data either to MS Excel or to a CSV file. You can view the ASP.NET profiler report to conduct further analysis as well. View Data and Diagnostic Attachments opens the Choose Diagnostic Data Adapter Attachment dialog box to select an adapter to analyse the result type. For example, you can select an IntelliTrace adapter, click OK and open the IntelliTrace summary for the test agent that was used in the load test.   Compare results This creates a set of reports that compares the data from two load test results using tables and bar charts. I have taken these screen shots from the MSDN documentation, I would highly recommend exploring the wealth of knowledge available on MSDN. Leaving Thoughts While load testing the application with an excessive load for a longer duration of time, i managed to bring the IIS to its knees by piling up a huge queue of requests waiting to be processed. This clearly means that the IIS had run out of threads as all the threads were busy processing existing request, one easy way of fixing this is by increasing the default number of allocated threads, but this might escalate the problem. The better suggestion is to try and drill down to the actual root cause of the problem. When ever the garbage collection runs it stops processing any pages so all requests that come in during that period are queued up, but realistically the garbage collection completes in fraction of a a second. To understand this better lets look at the .net heap, it is divided into large heap and small heap, anything greater than 85kB in size will be allocated to the Large object heap, the Large object heap is non compacting and remember large objects are expensive to move around, so if you are allocating something in the large object heap, make sure that you really need it! The small object heap on the other hand is divided into generations, so all objects that are supposed to be short-lived are suppose to live in Gen-0 and the long living objects eventually move to Gen-2 as garbage collection goes through.  As you can see in the picture below all < 85 KB size objects are first assigned to Gen-0, when Gen-0 fills up and a new object comes in and finds Gen-0 full, the garbage collection process is started, the process checks for all the dead objects and assigns them as the valid candidate for deletion to free up memory and promotes all the remaining objects in Gen-0 to Gen-1. So in the future when ever you clean up Gen-1 you have to clean up Gen-0 as well. When you fill up Gen – 0 again, all of Gen – 1 dead objects are drenched and rest are moved to Gen-2 and Gen-0 objects are moved to Gen-1 to free up Gen-0, but by this time your Garbage collection process has started to take much more time than it usually takes. Now as I mentioned earlier when garbage collection is being run all page requests that come in during that period are queued up. Does this explain why possibly page requests are getting queued up, apart from this it could also be the case that you are waiting for a long running database process to complete.      Lets explore the heap a bit more… What is really a case of crisis is when the objects are living long enough to make it to Gen-2 and then dying, this is definitely a high cost operation. But sometimes you need objects in memory, for example when you cache data you hold on to the objects because you need to use them right across the user session, which is acceptable. But if you wanted to see what extreme caching can do to your server then write a simple application that chucks in a lot of data in cache, run a load test over it for about 10-15 minutes, forcing a lot of data in memory causing the heap to run out of memory. If you get to such a state where you start running out of memory the IIS as a mode of recovery restarts the worker process. It is great way to free up all your memory in the heap but this would clear the cache. The problem with this is if the customer had 10 items in their shopping basket and that data was stored in the application cache, the user basket will now be empty forcing them either to get frustrated and go to a competitor website or if the customer is really patient, give it another try! How can you address this, well two ways of addressing this; 1. Workaround – A x86 bit processor only allows a maximum of 4GB of RAM, this means the machine effectively has around 3.4 GB of RAM available, the OS needs about 1.5 GB of RAM to run efficiently, the IIS and .net framework also need their share of memory, leaving you a heap of around 800 MB to play with. Because Team builds by default build your application in ‘Compile as any mode’ it means the application is build such that it will run in x86 bit mode if run on a x86 bit processor and run in a x64 bit mode if run on a x64 but processor. The problem with this is not all applications are really x64 bit compatible specially if you are using com objects or external libraries. So, as a quick win if you compiled your application in x86 bit mode by changing the compile as any selection to compile as x86 in the team build, you will be able to run your application on a x64 bit machine in x86 bit mode (WOW – By running Windows on Windows) and what that means is, you could use 8GB+ worth of RAM, if you take away everything else your application will roughly get a heap size of at least 4 GB to play with, which is immense. If you need a heap size of more than 4 GB you have either build a software for NASA or there is something fundamentally wrong in your application. 2. Solution – Now that you have put a workaround in place the IIS will not restart the worker process that regularly, which means you can take a breather and start working to get to the root cause of this memory leak. But this begs a question “How do I Identify possible memory leaks in my application?” Well i won’t say that there is one single tool that can tell you where the memory leak is, but trust me, ‘Performance Profiling’ is a great start point, it definitely gets you started in the right direction, let’s have a look at how. Performance Wizard - Start the Performance Wizard and select Instrumentation, this lets you measure function call counts and timings. Before running the performance session right click the performance session settings and chose properties from the context menu to bring up the Performance session properties page and as shown in the screen shot below, check the check boxes in the group ‘.NET memory profiling collection’ namely ‘Collect .NET object allocation information’ and ‘Also collect the .NET Object lifetime information’.    Now if you fire off the profiling session on your pages you will notice that the results allows you to view ‘Object Lifetime’ which shows you the number of objects that made it to Gen-0, Gen-1, Gen-2, Large heap, etc. Another great feature about the profile is that if your application has > 5% cases where objects die right after making to the Gen-2 storage a threshold alert is generated to alert you. Since you have the option to also view the most expensive methods and by capturing the IntelliTrace data you can drill in to narrow down to the line of code that is the root cause of the problem. Well now that we have seen how crucial memory management is and how easy Visual Studio Ultimate 2010 makes it for us to identify and reproduce the problem with the best of breed tools in the product. Caching One of the main ways to improve performance is Caching. Which basically means you tell the web server that instead of going to the database for each request you keep the data in the webserver and when the user asks for it you serve it from the webserver itself. BUT that can have consequences! Let’s look at some code, trust me caching code is not very intuitive, I define a cache key for almost all searches made through the common search page and cache the results. The approach works fine, first time i get the data from the database and second time data is served from the cache, significant performance improvement, EXCEPT when two users try to do the same operation and run into each other. But it is easy to handle this by adding the lock as you can see in the snippet below. So, as long as a user comes in and finds that the cache is empty, the user locks and starts to get the cache no more concurrency issues. But lets say you are processing 10 requests per second, by the time i have locked the operation to get the results from the database, 9 other users came in and found that the cache key is null so after i have come out and populated the cache they will still go in to get the results again. The application will still be faster because the next set of 10 users and so on would continue to get data from the cache. BUT if we added another null check after locking to build the cache and before actual call to the db then the 9 users who follow me would not make the extra trip to the database at all and that would really increase the performance, but didn’t i say that the code won’t be very intuitive, may be you should leave a comment you don’t want another developer to come in and think what a fresher why is he checking for the cache key null twice !!! The downside of caching is, you are storing the data outside of the database and the data could be wrong because the updates applied to the database would make the data cached at the web server out of sync. So, how do you invalidate the cache? Well if you only had one way of updating the data lets say only one entry point to the data update you can write some logic to say that every time new data is entered set the cache object to null. But this approach will not work as soon as you have several ways of feeding data to the system or your system is scaled out across a farm of web servers. The perfect solution to this is Micro Caching which means you cache the query for a set time duration and invalidate the cache after that set duration. The advantage is every time the user queries for that data with in the time span for which you have cached the results there are no calls made to the database and the data is served right from the server which makes the response immensely quick. Now figuring out the appropriate time span for which you micro cache the query results really depends on the application. Lets say your website gets 10 requests per second, if you retain the cache results for even 1 minute you will have immense performance gains. You would reduce 90% hits to the database for searching. Ever wondered why when you go to e-bookers.com or xpedia.com or yatra.com to book a flight and you click on the book button because the fare seems too exciting and you get an error message telling you that the fare is not valid any more. Yes, exactly => That is a cache failure! These travel sites or price compare engines are not going to hit the database every time you hit the compare button instead the results will be served from the cache, because the query results are micro cached, its a perfect trade-off, by micro caching the results the site gains 100% performance benefits but every once in a while annoys a customer because the fare has expired. But the trade off works in the favour of these sites as they are still able to process up to 30+ page requests per second which means cater to the site traffic by may be losing 1 customer every once in a while to a competitor who is also using a similar caching technique what are the odds that the user will not come back to their site sooner or later? Recap   Resources Below are some Key resource you might like to review. I would highly recommend the documentation, walkthroughs and videos available on MSDN. You can always make use of Fiddler to debug Web Performance Tests. Some community test extensions and plug ins available on Codeplex might also be of interest to you. The Road Ahead Thank you for taking the time out and reading this blog post, you may also want to read Part I and Part II if you haven’t so far. If you enjoyed the post, remember to subscribe to http://feeds.feedburner.com/TarunArora. Questions/Feedback/Suggestions, etc please leave a comment. Next ‘Load Testing in the cloud’, I’ll be working on exploring the possibilities of running Test controller/Agents in the Cloud. See you on the other side! Thank You!   Share this post : CodeProject

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• Know more about Enqueue Deadlock Detection

  - by Liu Maclean(???)

  ??? ORACLE ALLSTAR???????????????????,??????? ???????enqueue lock?????????3 ??????,????????????????????????????ora-00060 dead lock??process???3s: SQL> select * from v$version; BANNER ---------------------------------------------------------------- Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bi PL/SQL Release 10.2.0.5.0 - Production CORE 10.2.0.5.0 Production TNS for Linux: Version 10.2.0.5.0 - Production NLSRTL Version 10.2.0.5.0 - Production SQL> select * from global_name; GLOBAL_NAME -------------------------------------------------------------------------------- www.oracledatabase12g.com PROCESS A: set timing on; update maclean1 set t1=t1+1; PROCESS B: update maclean2 set t1=t1+1; PROCESS A: update maclean2 set t1=t1+1; PROCESS B: update maclean1 set t1=t1+1; ??3s? PROCESS A ?? ERROR at line 1: ORA-00060: deadlock detected while waiting for resource Elapsed: 00:00:03.02 ????Process A????????????? 3s,?????????????,??????? ?????????? ???????: SQL> col name for a30 SQL> col value for a5 SQL> col DESCRIB for a50 SQL> set linesize 140 pagesize 1400 SQL> SELECT x.ksppinm NAME, y.ksppstvl VALUE, x.ksppdesc describ 2 FROM SYS.x$ksppi x, SYS.x$ksppcv y 3 WHERE x.inst_id = USERENV ('Instance') 4 AND y.inst_id = USERENV ('Instance') 5 AND x.indx = y.indx 6 AND x.ksppinm='_enqueue_deadlock_scan_secs'; NAME VALUE DESCRIB ------------------------------ ----- -------------------------------------------------- _enqueue_deadlock_scan_secs 0 deadlock scan interval SQL> alter system set "_enqueue_deadlock_scan_secs"=18 scope=spfile; System altered. Elapsed: 00:00:00.01 SQL> startup force; ORACLE instance started. Total System Global Area 851443712 bytes Fixed Size 2100040 bytes Variable Size 738198712 bytes Database Buffers 104857600 bytes Redo Buffers 6287360 bytes Database mounted. Database opened. PROCESS A: SQL> set timing on; SQL> update maclean1 set t1=t1+1; 1 row updated. Elapsed: 00:00:00.06 Process B SQL> update maclean2 set t1=t1+1; 1 row updated. SQL> update maclean1 set t1=t1+1; Process A: SQL> SQL> alter session set events '10704 trace name context forever,level 10:10046 trace name context forever,level 8'; Session altered. SQL> update maclean2 set t1=t1+1; update maclean2 set t1=t1+1 * ERROR at line 1: ORA-00060: deadlock detected while waiting for resource  Elapsed: 00:00:18.05 ksqcmi: TX,90011,4a9 mode=6 timeout=21474836 WAIT #12: nam='enq: TX - row lock contention' ela= 2930070 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114759849120 WAIT #12: nam='enq: TX - row lock contention' ela= 2930636 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114762779801 WAIT #12: nam='enq: TX - row lock contention' ela= 2930439 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114765710430 *** 2012-06-12 09:58:43.089 WAIT #12: nam='enq: TX - row lock contention' ela= 2931698 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114768642192 WAIT #12: nam='enq: TX - row lock contention' ela= 2930428 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114771572755 WAIT #12: nam='enq: TX - row lock contention' ela= 2931408 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114774504207 DEADLOCK DETECTED ( ORA-00060 ) [Transaction Deadlock] The following deadlock is not an ORACLE error. It is a deadlock due to user error in the design of an application or from issuing incorrect ad-hoc SQL. The following information may aid in determining the deadlock: ??????Process A?’enq: TX – row lock contention’ ?????ORA-00060 deadlock detected????3s ??? 18s , ???hidden parameter “_enqueue_deadlock_scan_secs”?????,????????0? ??????????: SQL> alter system set "_enqueue_deadlock_scan_secs"=4 scope=spfile; System altered. Elapsed: 00:00:00.01 SQL> alter system set "_enqueue_deadlock_time_sec"=9 scope=spfile; System altered. Elapsed: 00:00:00.00 SQL> startup force; ORACLE instance started. Total System Global Area 851443712 bytes Fixed Size 2100040 bytes Variable Size 738198712 bytes Database Buffers 104857600 bytes Redo Buffers 6287360 bytes Database mounted. Database opened. SQL> set linesize 140 pagesize 1400 SQL> show parameter dead NAME TYPE VALUE ------------------------------------ -------------------------------- ------------------------------ _enqueue_deadlock_scan_secs integer 4 _enqueue_deadlock_time_sec integer 9 SQL> set timing on SQL> select * from maclean1 for update wait 8; T1 ---------- 11 Elapsed: 00:00:00.01 PROCESS B SQL> select * from maclean2 for update wait 8; T1 ---------- 3 SQL> select * from maclean1 for update wait 8; select * from maclean1 for update wait 8 PROCESS A SQL> select * from maclean2 for update wait 8; select * from maclean2 for update wait 8 * ERROR at line 1: ORA-30006: resource busy; acquire with WAIT timeout expired Elapsed: 00:00:08.00 ???????? ??? select for update wait?enqueue request timeout ?????8s? ,???????”_enqueue_deadlock_scan_secs”=4(deadlock scan interval),?4s???deadlock detected,????Process A????deadlock ???, ??????? ??Process A?????8s?raised??”ORA-30006: resource busy; acquire with WAIT timeout expired”??,??ORA-00060,?????process A???????? ????????”_enqueue_deadlock_time_sec”(requests with timeout <= this will not have deadlock detection)???,?enqueue request time < “_enqueue_deadlock_time_sec”?Server process?????dead lock detection,?????????enqueue request ??????timeout??????(_enqueue_deadlock_time_sec????5,?timeout<5s),???????????????;??????timeout>”_enqueue_deadlock_time_sec”???,Oracle????????????????????? ??????????: SQL> show parameter dead NAME TYPE VALUE ------------------------------------ -------------------------------- ------------------------------ _enqueue_deadlock_scan_secs integer 4 _enqueue_deadlock_time_sec integer 9 Process A: SQL> set timing on; SQL> select * from maclean1 for update wait 10; T1 ---------- 11 Process B: SQL> select * from maclean2 for update wait 10; T1 ---------- 3 SQL> select * from maclean1 for update wait 10; PROCESS A: SQL> select * from maclean2 for update wait 10; select * from maclean2 for update wait 10 * ERROR at line 1: ORA-00060: deadlock detected while waiting for resource Elapsed: 00:00:06.02 ??????? select for update wait 10?10s??, ?? 10s?????_enqueue_deadlock_time_sec???(9s),??Process A???????? ???????????????6s ???????_enqueue_deadlock_scan_secs?4s ? ???????????,???????????_enqueue_deadlock_scan_secs?????????3???? ??: enqueue lock?????????????? 1. ?????????deadlock detection??3s????, ????????_enqueue_deadlock_scan_secs(deadlock scan interval)???,??????0,????????_enqueue_deadlock_scan_secs?????????3???, ?_enqueue_deadlock_scan_secs=0 ??3s??, ?_enqueue_deadlock_scan_secs=4??6s??,????? 2. ???????_enqueue_deadlock_time_sec(requests with timeout <= this will not have deadlock detection)???,?enqueue request timeout< _enqueue_deadlock_time_sec(????5),?Server process?????????enqueue request timeout>_enqueue_deadlock_time_sec ????_enqueue_deadlock_scan_secs???????, ??request timeout??????select for update wait [TIMEOUT]??? ??: ???10.2.0.1?????????2?hidden parameter , ???patchset 10.2.0.3????? _enqueue_deadlock_time_sec, ?patchset 10.2.0.5??????_enqueue_deadlock_scan_secs? ?????RAC???????????10s, ???????_lm_dd_interval(dd time interval in seconds) ,????????8.0.6???? ???????????????,??????,  ?10g???????60s,?11g???????10s?  ???????11g??_lm_dd_interval?????????????,?????11g??LMD????????????,??????????RAC?LMD?Deadlock Detection???????CPU,???11g?Oracle????Team???LMD????????CPU????: ????????11g?LMD???????,???????11g??? UTS TRACE ????? DD???: SQL> select * from v$version; BANNER -------------------------------------------------------------------------------- Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production PL/SQL Release 11.2.0.3.0 - Production CORE 11.2.0.3.0 Production TNS for Linux: Version 11.2.0.3.0 - Production NLSRTL Version 11.2.0.3.0 - Production SQL> SQL> select * from global_name 2 ; GLOBAL_NAME -------------------------------------------------------------------------------- www.oracledatabase12g.com SQL> alter system set "_lm_dd_interval"=20 scope=spfile; System altered. SQL> startup force; ORACLE instance started. Total System Global Area 1570009088 bytes Fixed Size 2228704 bytes Variable Size 1325403680 bytes Database Buffers 234881024 bytes Redo Buffers 7495680 bytes Database mounted. Database opened. SQL> set linesize 140 pagesize 1400 SQL> show parameter lm_dd NAME TYPE VALUE ------------------------------------ -------------------------------- ------------------------------ _lm_dd_interval integer 20 SQL> select count(*) from gv$instance; COUNT(*) ---------- 2 instance 1: SQL> oradebug setorapid 12 Oracle pid: 12, Unix process pid: 8608, image: [email protected] (LMD0) ? LMD0??? UTS TRACE??RAC???????????? SQL> oradebug event 10046 trace name context forever,level 8:10708 trace name context forever,level 103: trace[rac.*] disk high; Statement processed. Elapsed: 00:00:00.00 SQL> update maclean1 set t1=t1+1; 1 row updated. instance 2: SQL> update maclean2 set t1=t1+1; 1 row updated. SQL> update maclean1 set t1=t1+1; Instance 1: SQL> update maclean2 set t1=t1+1; update maclean2 set t1=t1+1 * ERROR at line 1: ORA-00060: deadlock detected while waiting for resource Elapsed: 00:00:20.51 LMD0???UTS TRACE 2012-06-12 22:27:00.929284 : [kjmpbmsg:process][type 22][msg 0x7fa620ac85a8][from 1][seq 8148.0][len 192] 2012-06-12 22:27:00.929346 : [kjmxmpm][type 22][seq 0.0][msg 0x7fa620ac85a8][from 1] *** 2012-06-12 22:27:00.929 * kjddind: received DDIND msg with subtype x6 * reqp->dd_master_inst_kjxmddi == 1 * kjddind: dump sgh: 2012-06-12 22:27:00.929346*: kjddind: req->timestamp [0.15], kjddt [0.13] 2012-06-12 22:27:00.929346*: >> DDmsg:KJX_DD_REMOTE,TS[0.15],Inst 1->2,ddxid[id1,id2,inst:2097153,31,1],ddlock[0x95023930,829],ddMasterInst 1 2012-06-12 22:27:00.929346*: lock [0x95023930,829], op = [mast] 2012-06-12 22:27:00.929346*: reqp->timestamp [0.15], kjddt [0.13] 2012-06-12 22:27:00.929346*: kjddind: updated local timestamp [0.15] * kjddind: case KJX_DD_REMOTE 2012-06-12 22:27:00.929346*: ADD IO NODE WFG: 0 frame pointer 2012-06-12 22:27:00.929346*: PUSH: type=res, enqueue(0xffffffff.0xffffffff)=0xbbb9af40, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: PROCESS: type=res, enqueue(0xffffffff.0xffffffff)=0xbbb9af40, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: POP: type=res, enqueue(0xffffffff.0xffffffff)=0xbbb9af40, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: kjddopr[TX 0xe000c.0x32][ext 0x5,0x0]: blocking lock 0xbbb9a800, owner 2097154 of inst 2 2012-06-12 22:27:00.929346*: PUSH: type=txn, enqueue(0xffffffff.0xffffffff)=0xbbb9a800, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: PROCESS: type=txn, enqueue(0xffffffff.0xffffffff)=0xbbb9a800, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: ADD NODE TO WFG: type=txn, enqueue(0xffffffff.0xffffffff)=0xbbb9a800, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: POP: type=txn, enqueue(0xffffffff.0xffffffff)=0xbbb9a800, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: kjddopt: converting lock 0xbbce92f8 on 'TX' 0x80016.0x5d4,txid [2097154,34]of inst 2 2012-06-12 22:27:00.929346*: PUSH: type=res, enqueue(0xffffffff.0xffffffff)=0xbbce92f8, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: PROCESS: type=res, enqueue(0xffffffff.0xffffffff)=0xbbce92f8, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: ADD NODE TO WFG: type=res, enqueue(0xffffffff.0xffffffff)=0xbbce92f8, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929855 : GSIPC:AMBUF: rcv buff 0x7fa620aa8cd8, pool rcvbuf, rqlen 1102 2012-06-12 22:27:00.929878 : GSIPC:GPBMSG: new bmsg 0x7fa620aa8d48 mb 0x7fa620aa8cd8 msg 0x7fa620aa8d68 mlen 192 dest x100 flushsz -1 2012-06-12 22:27:00.929878*: << DDmsg:KJX_DD_REMOTE,TS[0.15],Inst 2->1,ddxid[id1,id2,inst:2097153,31,1],ddlock[0x95023930,829],ddMasterInst 1 2012-06-12 22:27:00.929878*: lock [0xbbce92f8,287], op = [mast] 2012-06-12 22:27:00.929878*: ADD IO NODE WFG: 0 frame pointer 2012-06-12 22:27:00.929923 : [kjmpbmsg:compl][msg 0x7fa620ac8588][typ p][nmsgs 1][qtime 0][ptime 0] 2012-06-12 22:27:00.929947 : GSIPC:PBAT: flush start. flag 0x79 end 0 inc 4.4 2012-06-12 22:27:00.929963 : GSIPC:PBAT: send bmsg 0x7fa620aa8d48 blen 224 dest 1.0 2012-06-12 22:27:00.929979 : GSIPC:SNDQ: enq msg 0x7fa620aa8d48, type 65521 seq 8325, inst 1, receiver 0, queued 1 012-06-12 22:27:00.929979 : GSIPC:SNDQ: enq msg 0x7fa620aa8d48, type 65521 seq 8325, inst 1, receiver 0, queued 1 2012-06-12 22:27:00.929996 : GSIPC:BSEND: flushing sndq 0xb491dd28, id 0, dcx 0xbc517770, inst 1, rcvr 0 qlen 0 1 2012-06-12 22:27:00.930014 : GSIPC:BSEND: no batch1 msg 0x7fa620aa8d48 type 65521 len 224 dest (1:0) 2012-06-12 22:27:00.930088 : kjbsentscn[0x0.3f72dc][to 1] 2012-06-12 22:27:00.930144 : GSIPC:SENDM: send msg 0x7fa620aa8d48 dest x10000 seq 8325 type 65521 tkts x1 mlen xe00110 2012-06-12 22:27:00.930531 : GSIPC:KSXPCB: msg 0x7fa620aa8d48 status 30, type 65521, dest 1, rcvr 0 WAIT #0: nam='ges remote message' ela= 1372 waittime=80 loop=0 p3=74 obj#=-1 tim=1339554420931640 2012-06-12 22:27:00.931728 : GSIPC:RCVD: ksxp msg 0x7fa620af6490 sndr 1 seq 0.8149 type 65521 tkts 1 2012-06-12 22:27:00.931746 : GSIPC:RCVD: watq msg 0x7fa620af6490 sndr 1, seq 8149, type 65521, tkts 1 2012-06-12 22:27:00.931763 : GSIPC:RCVD: seq update (0.8148)->(0.8149) tp -15 fg 0x4 from 1 pbattr 0x0 2012-06-12 22:27:00.931779 : GSIPC:TKT: collect msg 0x7fa620af6490 from 1 for rcvr 0, tickets 1 2012-06-12 22:27:00.931794 : kjbrcvdscn[0x0.3f72dc][from 1][idx 2012-06-12 22:27:00.931810 : kjbrcvdscn[no bscn dd_master_inst_kjxmddi == 1 * kjddind: dump sgh: NXTIN (nil) 0 wq 0 cvtops x0 0x0.0x0(ext 0x0,0x0)[0000-0000-00000000] inst 1 BLOCKER 0xbbb9a800 5 wq 1 cvtops x28 TX 0xe000c.0x32(ext 0x5,0x0)[20000-0002-00000022] inst 2 BLOCKED 0xbbce92f8 5 wq 2 cvtops x1 TX 0x80016.0x5d4(ext 0x2,0x0)[20000-0002-00000022] inst 2 NXTOUT (nil) 0 wq 0 cvtops x0 0x0.0x0(ext 0x0,0x0)[0000-0000-00000000] inst 1 2012-06-12 22:27:00.932058*: kjddind: req->timestamp [0.15], kjddt [0.15] 2012-06-12 22:27:00.932058*: >> DDmsg:KJX_DD_VALIDATE,TS[0.15],Inst 1->2,ddxid[id1,id2,inst:2097153,31,1],ddlock[0x95023930,829],ddMasterInst 1 2012-06-12 22:27:00.932058*: lock [(nil),0], op = [vald_dd] 2012-06-12 22:27:00.932058*: kjddind: updated local timestamp [0.15] * kjddind: case KJX_DD_VALIDATE *** 2012-06-12 22:27:00.932 * kjddvald called: kjxmddi stuff: * cont_lockp (nil) * dd_lockp 0x95023930 * dd_inst 1 * dd_master_inst 1 * sgh graph: NXTIN (nil) 0 wq 0 cvtops x0 0x0.0x0(ext 0x0,0x0)[0000-0000-00000000] inst 1 BLOCKER 0xbbb9a800 5 wq 1 cvtops x28 TX 0xe000c.0x32(ext 0x5,0x0)[20000-0002-00000022] inst 2 BLOCKED 0xbbce92f8 5 wq 2 cvtops x1 TX 0x80016.0x5d4(ext 0x2,0x0)[20000-0002-00000022] inst 2 NXTOUT (nil) 0 wq 0 cvtops x0 0x0.0x0(ext 0x0,0x0)[0000-0000-00000000] inst 1 POP WFG NODE: lock=(nil) * kjddvald: dump the PRQ: BLOCKER 0xbbb9a800 5 wq 1 cvtops x28 TX 0xe000c.0x32(ext 0x5,0x0)[20000-0002-00000022] inst 2 BLOCKED 0xbbce92f8 5 wq 2 cvtops x1 TX 0x80016.0x5d4(ext 0x2,0x0)[20000-0002-00000022] inst 2 * kjddvald: KJDD_NXTONOD ->node_kjddsg.dinst_kjddnd =1 * kjddvald: ... which is not my node, my subgraph is validated but the cycle is not complete Global blockers dump start:--------------------------------- DUMP LOCAL BLOCKER/HOLDER: block level 5 res [0x80016][0x5d4],[TX][ext 0x2,0x0] ??dead lock!!! ???????11.2.0.3???? RAC LMD???????????”_lm_dd_interval”????????????20s?  ???????10g?_lm_dd_interval???60s,??????Processes?????????????????,????????????Server Process????????60s??????11g?????(??????LMD???????)???????,???????????10s??? Enqueue Deadlock Detection? ?11g??? RAC?LMD???????hidden parameter ????”_lm_dd_interval”???,RAC????????????????,???????????: SQL> col name for a50 SQL> col describ for a60 SQL> col value for a20 SQL> set linesize 140 pagesize 1400 SQL> SELECT x.ksppinm NAME, y.ksppstvl VALUE, x.ksppdesc describ 2 FROM SYS.x$ksppi x, SYS.x$ksppcv y 3 WHERE x.inst_id = USERENV ('Instance') 4 AND y.inst_id = USERENV ('Instance') 5 AND x.indx = y.indx 6 AND x.ksppinm like '_lm_dd%'; NAME VALUE DESCRIB -------------------------------------------------- -------------------- ------------------------------------------------------------ _lm_dd_interval 20 dd time interval in seconds _lm_dd_scan_interval 5 dd scan interval in seconds _lm_dd_search_cnt 3 number of dd search per token get _lm_dd_max_search_time 180 max dd search time per token _lm_dd_maxdump 50 max number of locks to be dumped during dd validation _lm_dd_ignore_nodd FALSE if TRUE nodeadlockwait/nodeadlockblock options are ignored 6 rows selected.

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• encfs error while decoding the data

  - by migrator

  I have installed encfs and started using it to secure all my personal & office data and it was working absolutely fine until 2 hours back. The setup is like this. I have a folder in Copy folder called OfficeData which gets synchronized with my Copy folder When I login into the system I use the command encfs ~/Copy/OfficeData ~/Documents/OfficeData Once my work is over I dismount with the command fusermount -u ~/Documents/OfficeData All this data get synchronized with my desktop and with my mobile phone (as a backup) Today when I mounted, the folder got mounted by no directories and files present in that folder. I was worried and read man encfs which gave me to run the command encfs -v -f ~/Copy/OfficeData ~/Documents/OfficeData 2> encfs-OfficeData-report.txt. The below is the output of the file encfs-OfficeData-report.txt. The directory "/home/sri/Documents/OfficeData" does not exist. Should it be created? (y,n) 13:16:26 (main.cpp:523) Root directory: /home/sri/Copy/OfficeData/ 13:16:26 (main.cpp:524) Fuse arguments: (fg) (threaded) (keyCheck) encfs /home/sri/Documents/OfficeData -f -s -o use_ino -o default_permissions 13:16:26 (FileUtils.cpp:177) version = 20 13:16:26 (FileUtils.cpp:181) found new serialization format 13:16:26 (FileUtils.cpp:199) subVersion = 20100713 13:16:26 (Interface.cpp:165) checking if ssl/aes(3:0:2) implements ssl/aes(3:0:0) 13:16:26 (SSL_Cipher.cpp:370) allocated cipher ssl/aes, keySize 32, ivlength 16 13:16:26 (Interface.cpp:165) checking if ssl/aes(3:0:2) implements ssl/aes(3:0:0) 13:16:26 (SSL_Cipher.cpp:370) allocated cipher ssl/aes, keySize 32, ivlength 16 13:16:26 (FileUtils.cpp:1620) useStdin: 0 13:16:46 (Interface.cpp:165) checking if ssl/aes(3:0:2) implements ssl/aes(3:0:0) 13:16:46 (SSL_Cipher.cpp:370) allocated cipher ssl/aes, keySize 32, ivlength 16 13:16:49 (FileUtils.cpp:1628) cipher key size = 52 13:16:49 (Interface.cpp:165) checking if nameio/block(3:0:1) implements nameio/block(3:0:0) 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/UWbT-M-UKk1JpvNfN5uvOhGn: No such file or directory 13:16:49 (CipherFileIO.cpp:105) in setIV, current IV = 0, new IV = 4188221457101129840, fileIV = 0 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/UWbT-M-UKk1JpvNfN5uvOhGn 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/UWbT-M-UKk1JpvNfN5uvOhGn 13:16:49 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/UWbT-M-UKk1JpvNfN5uvOhGn: No such file or directory 13:16:49 (encfs.cpp:138) getattr error: No such file or directory 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/o94olxB3orqarqyFviHKZ,ZF: No such file or directory 13:16:49 (CipherFileIO.cpp:105) in setIV, current IV = 0, new IV = 16725694203599486310, fileIV = 0 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/o94olxB3orqarqyFviHKZ,ZF 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/o94olxB3orqarqyFviHKZ,ZF 13:16:49 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/o94olxB3orqarqyFviHKZ,ZF: No such file or directory 13:16:49 (encfs.cpp:138) getattr error: No such file or directory 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/tVglci2rgp9o8qE-m9AvX6JNj1lQs-ER0OvnxfOb30Z,3,: No such file or directory 13:16:49 (CipherFileIO.cpp:105) in setIV, current IV = 0, new IV = 1354483141023495884, fileIV = 0 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/tVglci2rgp9o8qE-m9AvX6JNj1lQs-ER0OvnxfOb30Z,3, 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/tVglci2rgp9o8qE-m9AvX6JNj1lQs-ER0OvnxfOb30Z,3, 13:16:49 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/tVglci2rgp9o8qE-m9AvX6JNj1lQs-ER0OvnxfOb30Z,3,: No such file or directory 13:16:49 (encfs.cpp:138) getattr error: No such file or directory 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/r1KIEqVkz-,7-6CobavHCSNn: No such file or directory 13:16:49 (CipherFileIO.cpp:105) in setIV, current IV = 0, new IV = 16720606331386655431, fileIV = 0 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/r1KIEqVkz-,7-6CobavHCSNn 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/r1KIEqVkz-,7-6CobavHCSNn 13:16:49 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/r1KIEqVkz-,7-6CobavHCSNn: No such file or directory 13:16:49 (encfs.cpp:138) getattr error: No such file or directory 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:16:49 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:16:49 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:16:49 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:16:49 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:16:49 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:16:49 (FileNode.cpp:127) calling setIV on (null) 13:16:49 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/r1KIEqVkz-,7-6CobavHCSNn: No such file or directory 13:16:49 (CipherFileIO.cpp:105) in setIV, current IV = 0, new IV = 16720606331386655431, fileIV = 0 13:16:49 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/r1KIEqVkz-,7-6CobavHCSNn 13:16:49 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/r1KIEqVkz-,7-6CobavHCSNn 13:16:49 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/r1KIEqVkz-,7-6CobavHCSNn: No such file or directory 13:16:49 (encfs.cpp:138) getattr error: No such file or directory 13:19:31 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:19:31 (FileNode.cpp:127) calling setIV on (null) 13:19:31 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/ 13:19:31 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/ 13:19:31 (encfs.cpp:685) doing statfs of /home/sri/Copy/OfficeData 13:19:32 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:19:32 (FileNode.cpp:127) calling setIV on (null) 13:19:32 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/LuT8R,DlpRnNH9b,fjWiKHKc: No such file or directory 13:19:32 (CipherFileIO.cpp:105) in setIV, current IV = 0, new IV = 13735228085838055696, fileIV = 0 13:19:32 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/LuT8R,DlpRnNH9b,fjWiKHKc 13:19:32 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/LuT8R,DlpRnNH9b,fjWiKHKc 13:19:32 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/LuT8R,DlpRnNH9b,fjWiKHKc: No such file or directory 13:19:32 (encfs.cpp:138) getattr error: No such file or directory 13:19:32 (encfs.cpp:685) doing statfs of /home/sri/Copy/OfficeData 13:19:32 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:19:32 (FileNode.cpp:127) calling setIV on (null) 13:19:32 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/UWbT-M-UKk1JpvNfN5uvOhGn: No such file or directory 13:19:32 (CipherFileIO.cpp:105) in setIV, current IV = 0, new IV = 4188221457101129840, fileIV = 0 13:19:32 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/UWbT-M-UKk1JpvNfN5uvOhGn 13:19:32 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/UWbT-M-UKk1JpvNfN5uvOhGn 13:19:32 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/UWbT-M-UKk1JpvNfN5uvOhGn: No such file or directory 13:19:32 (encfs.cpp:138) getattr error: No such file or directory 13:19:32 (MACFileIO.cpp:75) fs block size = 1024, macBytes = 8, randBytes = 0 13:19:32 (FileNode.cpp:127) calling setIV on (null) 13:19:32 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/o94olxB3orqarqyFviHKZ,ZF: No such file or directory 13:19:32 (CipherFileIO.cpp:105) in setIV, current IV = 0, new IV = 16725694203599486310, fileIV = 0 13:19:32 (DirNode.cpp:770) created FileNode for /home/sri/Copy/OfficeData/o94olxB3orqarqyFviHKZ,ZF 13:19:32 (encfs.cpp:134) getattr /home/sri/Copy/OfficeData/o94olxB3orqarqyFviHKZ,ZF 13:19:32 (RawFileIO.cpp:191) getAttr error on /home/sri/Copy/OfficeData/o94olxB3orqarqyFviHKZ,ZF: No such file or directory 13:19:32 (encfs.cpp:138) getattr error: No such file or directory 13:19:32 (encfs.cpp:213) getdir on /home/sri/Copy/OfficeData/ 13:19:32 (BlockNameIO.cpp:185) padding, _bx, finalSize = 208, 16, -192 13:19:32 (DirNode.cpp:132) error decoding filename: eWJrLh2dRFAY-7Brbsc,mTqf 13:19:32 (DirNode.cpp:132) error decoding filename: .encfs6.xml 13:19:32 (BlockNameIO.cpp:185) padding, _bx, finalSize = 218, 16, -202 13:19:32 (DirNode.cpp:132) error decoding filename: pvph9DkZ0BMPg2vN4UcfwuNU 13:24:10 (openssl.cpp:48) Allocating 41 locks for OpenSSL Please help me Thanks in advance.

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• The case of the phantom ADF developer (and other yarns)

  - by Chris Muir

  A few years of ADF experience means I see common mistakes made by different developers, some I regularly make myself.  This post is designed to assist beginners to Oracle JDeveloper Application Development Framework (ADF) avoid a common ADF pitfall, the case of the phantom ADF developer [add Scooby-Doo music here]. ADF Business Components - triggers, default table values and instead of views. Oracle's JDeveloper tutorials help with the A-B-Cs of ADF development, typically built on the nice 'n safe demo schema provided by with the Oracle database such as the HR demo schema. However it's not too long until ADF beginners, having built up some confidence from learning with the tutorials and vanilla demo schemas, start building ADF Business Components based upon their own existing database schema objects.  This is where unexpected problems can sneak in. The crime Developers may encounter a surprising error at runtime when editing a record they just created or updated and committed to the database, based on their own existing tables, namely the error: JBO-25014: Another user has changed the row with primary key oracle.jbo.Key[x] ...where X is the primary key value of the row at hand.  In a production environment with multiple users this error may be legit, one of the other users has updated the row since you queried it.  Yet in a development environment this error is just plain confusing.  If developers are isolated in their own database, creating and editing records they know other users can't possibly be working with, or all the other developers have gone home for the day, how is this error possible? There are no other users?  It must be the phantom ADF developer! [insert dramatic music here] The following picture is what you'll see in the Business Component Browser, and you'll receive a similar error message via an ADF Faces page: A false conclusion What can possibly cause this issue if it isn't our phantom ADF developer?  Doesn't ADF BC implement record locking, locking database records when the row is modified in the ADF middle-tier by a user?  How can our phantom ADF developer even take out a lock if this is the case?  Maybe ADF has a bug, maybe ADF isn't implementing record locking at all?  Shouldn't we see the error "JBO-26030: Failed to lock the record, another user holds the lock" as we attempt to modify the record, why do we see JBO-25014? : Let's verify that ADF is in fact issuing the correct SQL LOCK-FOR-UPDATE statement to the database. First we need to verify ADF's locking strategy.  It is determined by the Application Module's jbo.locking.mode property.  The default (as of JDev 11.1.1.4.0 if memory serves me correct) and recommended value is optimistic, and the other valid value is pessimistic. Next we need a mechanism to check that ADF is issuing the LOCK statements to the database.  We could ask DBAs to monitor locks with OEM, but optimally we'd rather not involve overworked DBAs in this process, so instead we can use the ADF runtime setting –Djbo.debugoutput=console.  At runtime this options turns on instrumentation within the ADF BC layer, which among a lot of extra detail displayed in the log window, will show the actual SQL statement issued to the database, including the LOCK statement we're looking to confirm. Setting our locking mode to pessimistic, opening the Business Components Browser of a JSF page allowing us to edit a record, say the CHARGEABLE field within a BOOKINGS record where BOOKING_NO = 1206, upon editing the record see among others the following log entries: [421] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[422] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[423] Where binding param 1: 1206  As can be seen on line 422, in fact a LOCK-FOR-UPDATE is indeed issued to the database.  Later when we commit the record we see: [441] OracleSQLBuilder: SAVEPOINT 'BO_SP'[442] OracleSQLBuilder Executing, Lock 1 DML on: BOOKINGS (Update)[443] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[444] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[445] Update binding param 1: N[446] Where binding param 2: 1206[447] BookingsView1 notify COMMIT ... [448] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [449] EntityCache close prepared statement ....and as a result the changes are saved to the database, and the lock is released. Let's see what happens when we use the optimistic locking mode, this time to change the same BOOKINGS record CHARGEABLE column again.  As soon as we edit the record we see little activity in the logs, nothing to indicate any SQL statement, let alone a LOCK has been taken out on the row. However when we save our records by issuing a commit, the following is recorded in the logs: [509] OracleSQLBuilder: SAVEPOINT 'BO_SP'[510] OracleSQLBuilder Executing doEntitySelect on: BOOKINGS (true)[511] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[512] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[513] Where binding param 1: 1205[514] OracleSQLBuilder Executing, Lock 2 DML on: BOOKINGS (Update)[515] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[516] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[517] Update binding param 1: Y[518] Where binding param 2: 1205[519] BookingsView1 notify COMMIT ... [520] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [521] EntityCache close prepared statement Again even though we're seeing the midtier delay the LOCK statement until commit time, it is in fact occurring on line 412, and released as part of the commit issued on line 419.  Therefore with either optimistic or pessimistic locking a lock is indeed issued. Our conclusion at this point must be, unless there's the unlikely cause the LOCK statement is never really hitting the database, or the even less likely cause the database has a bug, then ADF does in fact take out a lock on the record before allowing the current user to update it.  So there's no way our phantom ADF developer could even modify the record if he tried without at least someone receiving a lock error. Hmm, we can only conclude the locking mode is a red herring and not the true cause of our problem.  Who is the phantom? At this point we'll need to conclude that the error message "JBO-25014: Another user has changed" is somehow legit, even though we don't understand yet what's causing it. This leads onto two further questions, how does ADF know another user has changed the row, and what's been changed anyway? To answer the first question, how does ADF know another user has changed the row, the Fusion Guide's section 4.10.11 How to Protect Against Losing Simultaneous Updated Data , that details the Entity Object Change-Indicator property, gives us the answer: At runtime the framework provides automatic "lost update" detection for entity objects to ensure that a user cannot unknowingly modify data that another user has updated and committed in the meantime. Typically, this check is performed by comparing the original values of each persistent entity attribute against the corresponding current column values in the database at the time the underlying row is locked. Before updating a row, the entity object verifies that the row to be updated is still consistent with the current state of the database.  The guide further suggests to make this solution more efficient: You can make the lost update detection more efficient by identifying any attributes of your entity whose values you know will be updated whenever the entity is modified. Typical candidates include a version number column or an updated date column in the row.....To detect whether the row has been modified since the user queried it in the most efficient way, select the Change Indicator option to compare only the change-indicator attribute values. We now know that ADF BC doesn't use the locking mechanism at all to protect the current user against updates, but rather it keeps a copy of the original record fetched, separate to the user changed version of the record, and it compares the original record against the one in the database when the lock is taken out.  If values don't match, be it the default compare-all-columns behaviour, or the more efficient Change Indicator mechanism, ADF BC will throw the JBO-25014 error. This leaves one last question.  Now we know the mechanism under which ADF identifies a changed row, what we don't know is what's changed and who changed it? The real culprit What's changed?  We know the record in the mid-tier has been changed by the user, however ADF doesn't use the changed record in the mid-tier to compare to the database record, but rather a copy of the original record before it was changed.  This leaves us to conclude the database record has changed, but how and by who? There are three potential causes: Database triggers The database trigger among other uses, can be configured to fire PLSQL code on a database table insert, update or delete.  In particular in an insert or update the trigger can override the value assigned to a particular column.  The trigger execution is actioned by the database on behalf of the user initiating the insert or update action. Why this causes the issue specific to our ADF use, is when we insert or update a record in the database via ADF, ADF keeps a copy of the record written to the database.  However the cached record is instantly out of date as the database triggers have modified the record that was actually written to the database.  Thus when we update the record we just inserted or updated for a second time to the database, ADF compares its original copy of the record to that in the database, and it detects the record has been changed – giving us JBO-25014. This is probably the most common cause of this problem. Default values A second reason this issue can occur is another database feature, default column values.  When creating a database table the schema designer can define default values for specific columns.  For example a CREATED_BY column could be set to SYSDATE, or a flag column to Y or N.  Default values are only used by the database when a user inserts a new record and the specific column is assigned NULL.  The database in this case will overwrite the column with the default value. As per the database trigger section, it then becomes apparent why ADF chokes on this feature, though it can only specifically occur in an insert-commit-update-commit scenario, not the update-commit-update-commit scenario. Instead of trigger views I must admit I haven't double checked this scenario but it seems plausible, that of the Oracle database's instead of trigger view (sometimes referred to as instead of views).  A view in the database is based on a query, and dependent on the queries complexity, may support insert, update and delete functionality to a limited degree.  In order to support fully insertable, updateable and deletable views, Oracle introduced the instead of view, that gives the view designer the ability to not only define the view query, but a set of programmatic PLSQL triggers where the developer can define their own logic for inserts, updates and deletes. While this provides the database programmer a very powerful feature, it can cause issues for our ADF application.  On inserting or updating a record in the instead of view, the record and it's data that goes in is not necessarily the data that comes out when ADF compares the records, as the view developer has the option to practically do anything with the incoming data, including throwing it away or pushing it to tables which aren't used by the view underlying query for fetching the data. Readers are at this point reminded that this article is specifically about how the JBO-25014 error occurs in the context of 1 developer on an isolated database.  The article is not considering how the error occurs in a production environment where there are multiple users who can cause this error in a legitimate fashion.  Assuming none of the above features are the cause of the problem, and optimistic locking is turned on (this error is not possible if pessimistic locking is the default mode *and* none of the previous causes are possible), JBO-25014 is quite feasible in a production ADF application if 2 users modify the same record. At this point under project timelines pressure, the obvious fix for developers is to drop both database triggers and default values from the underlying tables.  However we must be careful that these legacy constructs aren't used and assumed to be in place by other legacy systems.  Dropping the database triggers or default value that the existing Oracle Forms  applications assumes and requires to be in place could cause unexpected behaviour and bugs in the Forms application.  Proficient software engineers would recognize such a change may require a partial or full regression test of the existing legacy system, a potentially costly and timely exercise, not ideal. Solving the mystery once and for all Luckily ADF has built in functionality to deal with this issue, though it's not a surprise, as Oracle as the author of ADF also built the database, and are fully aware of the Oracle database's feature set.  At the Entity Object attribute level, the Refresh After Insert and Refresh After Update properties.  Simply selecting these instructs ADF BC after inserting or updating a record to the database, to expect the database to modify the said attributes, and read a copy of the changed attributes back into its cached mid-tier record.  Thus next time the developer modifies the current record, the comparison between the mid-tier record and the database record match, and JBO-25014: Another user has changed" is no longer an issue. [Post edit - as per the comment from Oracle's Steven Davelaar below, as he correctly points out the above solution will not work for instead-of-triggers views as it relies on SQL RETURNING clause which is incompatible with this type of view] Alternatively you can set the Change Indicator on one of the attributes.  This will work as long as the relating column for the attribute in the database itself isn't inadvertently updated.  In turn you're possibly just masking the issue rather than solving it, because if another developer turns the Change Indicator back on the original issue will return.

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• Why does ffmpeg stop randomly in the middle of a process?

  - by acidzombie24

  ffmpeg feels like its taking a long time. I then look at my output file and i see it stops between 6 and 8mbs. A fully encoded file is about 14mb. Why does ffmpeg stop? My code locks up on StandardOutput.ReadToEnd();. I had to kill the process (after seeing it not move for more then 10 seconds when i see it update every second previously) then i get the results of stdout and err. stdout is "" stderr is below. The output msg shows the filesize ended. I also see a drop in my CPU usage when it stops. I copyed the argument from visual studios. CD to the same working directory and ran the cmd (bin/ffmpeg) and pasted the argument. It was able to complete. int soundProcess(string infn, string outfn) { string aa, aa2; aa = aa2 = "DEAD"; var app = new Process(); app.StartInfo.UseShellExecute = false; app.StartInfo.RedirectStandardOutput = true; app.StartInfo.RedirectStandardError = true; //*/ app.StartInfo.FileName = @"bin\ffmpeg.exe"; app.StartInfo.Arguments = string.Format(@"-i ""{0}"" -ab 192k -y {2} ""{1}""", infn, outfn, param); app.Start(); try { app.PriorityClass = ProcessPriorityClass.BelowNormal; } catch (Exception ex) { if (!Regex.IsMatch(ex.Message, @"Cannot process request because the process .*has exited")) throw ex; } aa = app.StandardOutput.ReadToEnd(); aa2 = app.StandardError.ReadToEnd(); app.WaitForExit(); if (aa2.IndexOf("could not find codec parameters") != -1) return 1; else if (aa == "DEAD" || aa2 == "DEAD") return -1; else if (aa2.Length != 0) return -2; else return 0; } The output of stderr. stdout is empty. FFmpeg version SVN-r15815, Copyright (c) 2000-2008 Fabrice Bellard, et al. configuration: --enable-memalign-hack --enable-postproc --enable-swscale --enable-gpl --enable-libfaac --enable-libfaad --enable-libgsm --enable-libmp3lame --enable-libvorbis --enable-libtheora --enable-libx264 --enable-libxvid --disable-ffserver --disable-vhook --enable-avisynth --enable-pthreads libavutil 49.12. 0 / 49.12. 0 libavcodec 52. 3. 0 / 52. 3. 0 libavformat 52.23. 1 / 52.23. 1 libavdevice 52. 1. 0 / 52. 1. 0 libswscale 0. 6. 1 / 0. 6. 1 libpostproc 51. 2. 0 / 51. 2. 0 built on Nov 13 2008 10:28:29, gcc: 4.2.4 (TDM-1 for MinGW) Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'C:\dev\src\trunk\prjname\prjname\App_Data/temp/m/o/6304266424778814852': Duration: 00:12:53.36, start: 0.000000, bitrate: 154 kb/s Stream #0.0(und): Audio: aac, 44100 Hz, stereo, s16 Output #0, ipod, to 'C:\dev\src\trunk\prjname\prjname\App_Data\temp\m\o\2.m4a': Stream #0.0(und): Audio: libfaac, 44100 Hz, stereo, s16, 192 kb/s Stream mapping: Stream #0.0 -> #0.0 Press [q] to stop encoding size= 87kB time=4.74 bitrate= 150.7kbits/s size= 168kB time=9.06 bitrate= 151.9kbits/s size= 265kB time=14.28 bitrate= 151.8kbits/s size= 377kB time=20.29 bitrate= 152.1kbits/s size= 487kB time=26.22 bitrate= 152.1kbits/s size= 594kB time=32.02 bitrate= 152.1kbits/s size= 699kB time=37.64 bitrate= 152.1kbits/s size= 808kB time=43.54 bitrate= 152.0kbits/s size= 930kB time=50.09 bitrate= 152.2kbits/s size= 1058kB time=57.05 bitrate= 152.0kbits/s size= 1193kB time=64.23 bitrate= 152.1kbits/s size= 1329kB time=71.63 bitrate= 152.0kbits/s size= 1450kB time=78.16 bitrate= 152.0kbits/s size= 1578kB time=85.05 bitrate= 152.0kbits/s size= 1706kB time=92.00 bitrate= 152.0kbits/s size= 1836kB time=98.94 bitrate= 152.0kbits/s size= 1971kB time=106.25 bitrate= 151.9kbits/s size= 2107kB time=113.57 bitrate= 152.0kbits/s size= 2214kB time=119.33 bitrate= 152.0kbits/s size= 2345kB time=126.39 bitrate= 152.0kbits/s size= 2479kB time=133.56 bitrate= 152.0kbits/s size= 2611kB time=140.76 bitrate= 152.0kbits/s size= 2745kB time=147.91 bitrate= 152.1kbits/s size= 2880kB time=155.20 bitrate= 152.0kbits/s size= 3013kB time=162.40 bitrate= 152.0kbits/s size= 3146kB time=169.58 bitrate= 152.0kbits/s size= 3277kB time=176.61 bitrate= 152.0kbits/s size= 3412kB time=183.90 bitrate= 152.0kbits/s size= 3540kB time=190.80 bitrate= 152.0kbits/s size= 3670kB time=197.81 bitrate= 152.0kbits/s size= 3805kB time=205.08 bitrate= 152.0kbits/s size= 3932kB time=211.93 bitrate= 152.0kbits/s size= 4052kB time=218.38 bitrate= 152.0kbits/s size= 4171kB time=224.82 bitrate= 152.0kbits/s size= 4277kB time=230.55 bitrate= 152.0kbits/s size= 4378kB time=235.96 bitrate= 152.0kbits/s size= 4486kB time=241.79 bitrate= 152.0kbits/s size= 4592kB time=247.50 bitrate= 152.0kbits/s size= 4698kB time=253.21 bitrate= 152.0kbits/s size= 4804kB time=258.95 bitrate= 152.0kbits/s size= 4906kB time=264.41 bitrate= 152.0kbits/s size= 5012kB time=270.09 bitrate= 152.0kbits/s size= 5118kB time=275.85 bitrate= 152.0kbits/s size= 5234kB time=282.10 bitrate= 152.0kbits/s size= 5331kB time=287.39 bitrate= 151.9kbits/s size= 5445kB time=293.55 bitrate= 152.0kbits/s size= 5555kB time=299.40 bitrate= 152.0kbits/s size= 5665kB time=305.37 bitrate= 152.0kbits/s size= 5766kB time=310.80 bitrate= 152.0kbits/s size= 5876kB time=316.70 bitrate= 152.0kbits/s size= 5984kB time=322.50 bitrate= 152.0kbits/s size= 6094kB time=328.49 bitrate= 152.0kbits/s size= 6212kB time=334.76 bitrate= 152.0kbits/s size= 6327kB time=340.99 bitrate= 152.0kbits/s

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• Drawing lines between views in a TableLayout

  - by RiThBo

  Firstly - sorry if you saw my other question which I deleted. My question was flawed. Here is a better version If I have two views, how do I draw a (straight) line between them when one of them is touched? The line needs to be dynamic so it can follow the finger until it reaches the second view where it "locks on". So, when view1 is touched a straight line is drawn which then follows the finger until it reaches view2. I created a LineView class that extends view, but I don't how to proceed. I read some tutorials but none show how to do this. I think I need to get the coordinates of both view, and then create a path which "updates" on MotionEvent. I can get the coordinates and the ids of the views I want to draw a line between, but the line that I try to draw between them either goes above it, or the line does not reach past the width and height of the view. Any advice/code/clarity would be much appreciated! Here is some code: My layout. I want to draw a line between two views contained in theTableLayout.# <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/activity_game_relative_layout" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <TableLayout android:layout_marginTop="35dp" android:layout_marginBottom="35dp" android:id="@+id/tableLayout1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" > <TableRow android:id="@+id/table_row_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="5dip" > <com.example.view.DotView android:id="@+id/game_dot_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="10dp" android:layout_marginLeft="10dp" android:layout_marginRight="10dp" android:layout_marginTop="10dp" /> <com.example.view.DotView android:id="@+id/game_dot_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="10dp" android:layout_marginLeft="10dp" android:layout_marginRight="10dp" android:layout_marginTop="10dp" /> <com.example.view.DotView android:id="@+id/game_dot_3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="10dp" android:layout_marginLeft="10dp" android:layout_marginRight="10dp" android:layout_marginTop="10dp" /> </TableRow> <TableRow android:id="@+id/table_row_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="5dip" > <com.example.view.DotView android:id="@+id/game_dot_7" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="10dp" android:layout_marginLeft="10dp" android:layout_marginRight="10dp" android:layout_marginTop="10dp" /> <com.example.view.DotView android:id="@+id/game_dot_8" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="10dp" android:layout_marginLeft="10dp" android:layout_marginRight="10dp" android:layout_marginTop="10dp" /> <com.example.dotte.DotView android:id="@+id/game_dot_9" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="10dp" android:layout_marginLeft="10dp" android:layout_marginRight="10dp" android:layout_marginTop="10dp" /> </TableRow> </TableLayout> </RelativeLayout> This is my LineView class. I use this to try and draw the actual line between the points. public class LineView extends View { Paint paint = new Paint(); float startingX, startingY, endingX, endingY; public LineView(Context context) { super(context); // TODO Auto-generated constructor stub paint.setColor(Color.BLACK); paint.setStrokeWidth(10); } public void setPoints(float startX, float startY, float endX, float endY) { startingX = startX; startingY = startY; endingX = endX; endingY = endY; invalidate(); } @Override public void onDraw(Canvas canvas) { canvas.drawLine(startingX, startingY, endingX, endingY, paint); } } And this is my Activity. public class Game extends Activity { DotView dv1, dv2, dv3, dv4, dv5, dv6, dv7; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_game); getWindow().getDecorView().setSystemUiVisibility( View.SYSTEM_UI_FLAG_LOW_PROFILE); findDotIds(); RelativeLayout rl = (RelativeLayout) findViewById(R.id.activity_game_relative_layout); LineView lv = new LineView(this); lv.setPoints(dv1.getLeft(), dv1.getTop(), dv7.getLeft(), dv7.getTop()); rl.addView(lv); // TODO: Get the coordinates of all the dots in the TableLayout. Use view tree observer. } private void findDotIds() { // TODO Auto-generated method stub dv1 = (DotView) findViewById(R.id.game_dot_1); dv2 = (DotView) findViewById(R.id.game_dot_2); dv3 = (DotView) findViewById(R.id.game_dot_3); dv4 = (DotView) findViewById(R.id.game_dot_4); dv5 = (DotView) findViewById(R.id.game_dot_5); dv6 = (DotView) findViewById(R.id.game_dot_6); dv7 = (DotView) findViewById(R.id.game_dot_7); } } The views I want to draw lines between are in the TableLayout.

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• CodePlex Daily Summary for Tuesday, March 20, 2012

  CodePlex Daily Summary for Tuesday, March 20, 2012Popular ReleasesNearforums - ASP.NET MVC forum engine: Nearforums v8.0: Version 8.0 of Nearforums, the ASP.NET MVC Forum Engine, containing new features: Internationalization Custom authentication provider Access control list for forums and threads Webdeploy package checksum: abc62990189cf0d488ef915d4a55e4b14169bc01BIDS Helper: BIDS Helper 1.6: This beta release is the first to support SQL Server 2012 (in addition to SQL Server 2005, 2008, and 2008 R2). Since it is marked as a beta release, we are looking for bug reports in the next few months as you use BIDS Helper on real projects. In addition to getting all existing BIDS Helper functionality working appropriately in SQL Server 2012 (SSDT), the following features are new... Analysis Services Tabular Smart Diff Tabular Actions Editor Tabular HideMemberIf Tabular Pre-Build ...JavaScript Web Resource Manager for Microsoft Dynamics CRM 2011: JavaScript Web Resource Manager (1.2.1420.191): BUG FIXED : When loading scripts from disk, the import of the web resource didn't do anything When scripts were saved to disk, it wasn't possible to edit them with an editorSQL Monitor - managing sql server performance: SQLMon 4.2 alpha 12: 1. improved process visualizer, now shows how many dead locks, and what are the locked objects 2. fixed some other problems.Json.NET: Json.NET 4.5 Release 1: New feature - Windows 8 Metro build New feature - JsonTextReader automatically reads ISO strings as dates New feature - Added DateFormatHandling to control whether dates are written in the MS format or ISO format, with ISO as the default New feature - Added DateTimeZoneHandling to control reading and writing DateTime time zone details New feature - Added async serialize/deserialize methods to JsonConvert New feature - Added Path to JsonReader/JsonWriter/ErrorContext and exceptions w...SCCM Client Actions Tool: SCCM Client Actions Tool v1.11: SCCM Client Actions Tool v1.11 is the latest version. It comes with following changes since last version: Fixed a bug when ping and cmd.exe kept running in endless loop after action progress was finished. Fixed update checking from Codeplex RSS feed. The tool is downloadable as a ZIP file that contains four files: ClientActionsTool.hta – The tool itself. Cmdkey.exe – command line tool for managing cached credentials. This is needed for alternate credentials feature when running the HTA...WebSocket4Net: WebSocket4Net 0.5: Changes in this release fixed the wss's default port bug improved JsonWebSocket supported set client access policy protocol for silverlight fixed a handshake issue in Silverlight fixed a bug that "Host" field in handshake hadn't contained port if the port is not default supported passing in Origin parameter for handshaking supported reacting pings from server side fixed a bug in data sending fixed the bug sending a closing handshake with no message which would cause an excepti...SuperWebSocket, a .NET WebSocket Server: SuperWebSocket 0.5: Changes included in this release: supported closing handshake queue checking improved JSON subprotocol supported sending ping from server to client fixed a bug about sending a closing handshake with no message refactored the code to improve protocol compatibility fixed a bug about sub protocol configuration loading in Mono improved BasicSubProtocol added JsonWebSocketSessionDaun Management Studio: Daun Management Studio 0.1 (Alpha Version): These are these the alpha application packages for Daun Management Studio to manage MongoDB Server. Please visit our official website http://www.daun-project.comSurvey™ - web survey & form engine: Survey™ 2.0: The new stable Survey™ Project 2.0.0.1 version contains many new features like: Technical changes: - Use of Jquery, ASTreeview, Tabs, Tooltips and new menuprovider Features & Bugfixes: Survey list and search function Folder structure for surveys New Menustructure Library list New Library fields User list and search functions Layout options for a survey with CSS, page header and footer New IP filter security feature Enhanced Token Management New Question fields as ID, Alias...RiP-Ripper & PG-Ripper: RiP-Ripper 2.9.28: changes NEW: Added Support for "PixHub.eu" linksSmartNet: V1.0.0.0: DY SmartNet ?????? V1.0callisto: callisto 2.0.21: Added an option to disable local host detection.Javascript .NET: Javascript .NET v0.6: Upgraded to the latest stable branch of v8 (/tags/3.9.18), and switched to using their scons build system. We no longer include v8 source code as part of this project's source code. Simultaneous multithreaded use of v8 now supported (v8 Isolates), although different contexts may not share objects or call each other. 64-bit .Net 4.0 DLL now included. (Download now includes x86 and x64 for both .Net 3.5 and .Net 4.0.)MyRouter (Virtual WiFi Router): MyRouter 1.0.6: This release should be more stable there were a few bug fixes including the x64 issue as well as an error popping up when MyRouter started this was caused by a NULL valueGoogle Books Downloader for Windows: Google Books Downloader-2.0.0.0.: Google Books DownloaderFinestra Virtual Desktops: 2.5.4501: This is a very minor update release. Please see the information about the 2.5 and 2.5.4500 releases for more information on recent changes. This update did not even have an automatic update triggered for it. Adds error checking and reporting to all threads, not only those with message loopsAcDown????? - Anime&Comic Downloader: AcDown????? v3.9.2: ?? ●AcDown??????????、??、??????，????1M，????，????，?????????????????????????。???????????Acfun、????(Bilibili)、??、??、YouTube、??、???、??????、SF????、????????????。??????AcPlay?????，??????、????????????????。 ● AcDown???????????????????????????，???，???????????????????。 ● AcDown???????C#??，????.NET Framework 2.0??。?????"Acfun?????"。 ????32??64? Windows XP/Vista/7/8 ????????????? ??：????????Windows XP???,?????????.NET Framework 2.0???(x86)，?????"?????????"??? ??????????????，??????????： ??"AcDo...ArcGIS Editor for OpenStreetMap: ArcGIS Editor for OSM 2.0 Release Candidate: Your feedback is welcome - and this is your last chance to get your fixes in for this version! Includes installer for both Feature Server extension and Desktop extension, enhanced functionality for the Desktop tools, and enhanced built-in Javascript Editor for the Feature Server component. This release candidate includes fixes to beta 4 that accommodate domain users for setting up the Server Component, and fixes for reporting/uploading references tracked in the revision table. See Code In-P...C.B.R. : Comic Book Reader: CBR 0.6: 20 Issue trackers are closed and a lot of bugs too Localize view is now MVVM and delete is working. Added the unused flag (take care that it goes to true only when displaying screen elements) Backstage - new input/output format choice control for the conversion Backstage - Add display, behaviour and register file type options in the extended options dialog Explorer list view has been transformed to a custom control. New group header, colunms order and size are saved Single insta...New Projects{3S} SQL Smart Security "Protect your T-SQL know-how!": {3S} SQL Smart Security is an add-in which can be installed in Microsoft SQL Server Management Studio (SSMS). It enables software companies to create a secured content for database objects. The add-in brings much higher level of protection in comparison with SQL Server built in WITH ENCRYPTION feature.BETA - Content Slider for SharePoint 2010 / Office 365: SharePoint Banner / SharePoint 2010 Sliding Banner / Content Slider tools in Office 365/ Sliding Content in SharePoint is a general tool which could be used for sliding Banners or any other sliding content to be placed on any Office 365 / SharePoint 2010 / SharePoint Foundation.BF3 Development Server: The main issue of this project is to deliver a test server to all developers working on RCon (Remote-Administration-Console) Tools for Battlefield 3. Actually the only possibility to test the work made is to hire a real Game Server. BizTalk Server 2010 TCP/IP Adapter: This project is migration of existing BizTalk server 2009 TCPIP adapter to BizTalk server 2010. I have made few configuration changes which are making this adapter and installation compatible to BizTalk Server 2010. I have not modified adapter source code.BryhtCommon: It`s for easy to develope WP7 ,it contains some useful method Bug.Net Defect Tracking Components: Bug.Net server-side controls and components to add defect (bug) tracking to your current ASP.NET website.Customize Survey With Client Object Model: Customize OOB Survey/Vote/Poll in Share?Point With Client Object Model Visit http://swatipoint.blogspot.in/2011/12/sharepoint-client-object-modellist.html for more detailsDropboxToDo: A simple todo, synchronizing by Dropbox or, in future, by SkydriveFoggy: Foggy is a WPF dashboard for FogBugz information.Fort Myers High School Website: A website for Fort Myers High School in Fort Myers, Florida. This website will allow for both students and parents to better interact with the school. Developed in ASP.net (C#).Gonte.DataAccess: Data access for NET. It's developed in C#.Gonte.ObjectModel: Metadata about objects. It's developed in C#Gonte.SqlGenerator: Sql Generator It's developed in C#.kLib: This project space is for datastructures and classes, which should always be available. Any developer should use these in their projects. Liuyi.Phone.CharmScreen: Liuyi.Phone.CharmScreen Liuyi windows phone appLoU: Lord of Ultima helper suite.Managing Supplies: This WP7 project is able to manage your own suppliesNAV Fixed Assets 2012: Changes related to 'Dossier Fiscal' in Microsoft Dynamics NAV 2009 - New Model 30 - Changes to model 31 and model 32NCAA Tourney DotNetNuke Module: The NCAA Tourney is a DotNetNuke 3.X - 6.X module that allows you to add a NCAA tournament to your portal. You can allow users to record their picks for the tournament and then manage the outcome of the tournament calculating the winner of your tourney based on customizable point system. The module has been designed to be very user friendly and efficient for the end user as well as the administrator of the tournament.nothing here anymore: nothing here anymoreOrchard Dream Store Project: A simple website using Orchard CMS. For a school projectPowerShell Management Library for TEM: A project to provide a PowerShell functionality for managing your Tivoli Endpoint Manager (built upon BigFix technology). You can locally or remotely manage endpoints and relays via these simple and easy to use PowerShell Module.PrismWebBuilder: Web Builder ProjectProjeto Northwind: Northwind - FPUQLCF: QLCFShipwire API: Shipwire makes it easier for consumers of Shipwire's international shipment fulfilment service to integrate their XML API quickly and easily. Current features are: Inventory Service Rate Service (Shipping Costs) Future features are: Order Entry Service Order Tracking ServiceSmith XNA tools: Smith's XNA tools is a set of useful that i make to improve some basics features to XNA and make the Game Design More Easy.ST Recover: ST Recover can read Atari ST floppy disks on a PC under Windows, including special formats as 800 or 900 KB and damaged or desynchronized disks, and produces standard .ST disk image files. Then the image files can be read in ST emulators as WinSTon or Steem.SyncSMS: Windows desktop client for the Android App SyncSMS. This code is not affiliated with SyncSMS in any way,tempzz: tempzzTruxtor: Truxtor modular concept for electronic gadgetsTT SA TEST1: TT SA Test 1VisualQuantCode: Neuroquants is a library in c# for quants It's developed in c#.Weeps: Generate Bass and drum line in type of midi to be guitar's backing track that was playing by userxxtest: xxtest???-????? "???????????": ?????-????????? ???????????? Digital Design 2012. ??? ????. ?????? ?: ?????????????????? ??????? ?????. ??????? ?????????? ????????? ????????. ?????????? ?????????????? ??????? ??????? ? ????? ???????????? Digital Design 2012.????? ???????????? Digital Design 2012. ??? ????. ?????? ?: ?????????????????? ??????? ?????. ??????? ?????????? ????????? ????????. ?????????? ?????????????? ??????? ??????? ? ????? ???????????? Digital Design 2012.

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• NSOutlineView not refreshing when objects added to managed object context from NSOperations

  - by John Gallagher

  Background Cocoa app using core data Two processes - daemon and a main UI Daemon constantly writing to a data store UI process reads from same data store NSOutlineView in UI is bound to an NSTreeController which is bound to Application with key path of delegate.interpretedMOC What I want When the UI is activated, the outline view should update with the latest data inserted by the daemon. The Problem Main Thread Approach I fetch all the entities I'm interested in, then iterate over them, doing refreshObject:mergeChanges:YES. This works OK - the items get refreshed correctly. However, this is all running on the main thread, so the UI locks up for 10-20 seconds whilst it refreshes. Fine, so let's move these refreshes to NSOperations that run in the background instead. NSOperation Multithreaded Approach As soon as I move the refreshObject:mergeChanges: call into an NSOperation, the refresh no longer works. When I add logging messages, it's clear that the new objects are loaded in by the NSOperation subclass and refreshed. Not only that, but they are What I've tried I've messed around with this for 2 days solid and tried everything I can think of. Passing objectIDs to the NSOperation to refresh instead of an entity name. Resetting the interpretedMOC at various points - after the data refresh and before the outline view reload. I'd subclassed NSOutlineView. I discarded my subclass and set the view back to being an instance of NSOutlineView, just in case there was any funny goings on here. Added a rearrangeObjects call to the NSTreeController before reloading the NSOutlineView data. Made sure I had set the staleness interval to 0 on all managed object contexts I was using. I've got a feeling this problem is somehow related to caching core data objects in memory. But I've totally exhausted all my ideas on how I get this to work. I'd be eternally grateful of any ideas anyone else has. Code Main Thread Approach // In App Delegate -(void)applicationDidBecomeActive:(NSNotification *)notification { // Delay to allow time for the daemon to save [self performSelector:@selector(refreshTrainingEntriesAndGroups) withObject:nil afterDelay:3]; } -(void)refreshTrainingEntriesAndGroups { NSSet *allTrainingGroups = [[[NSApp delegate] interpretedMOC] fetchAllObjectsForEntityName:kTrainingGroup]; for(JGTrainingGroup *thisTrainingGroup in allTrainingGroups) [interpretedMOC refreshObject:thisTrainingGroup mergeChanges:YES]; NSError *saveError = nil; [interpretedMOC save:&saveError]; [windowController performSelectorOnMainThread:@selector(refreshTrainingView) withObject:nil waitUntilDone:YES]; } // In window controller class -(void)refreshTrainingView { [trainingViewTreeController rearrangeObjects]; // Didn't really expect this to have any effect. And it didn't. [trainingView reloadData]; } NSOperation Multithreaded Approach // In App Delegate -(void)refreshTrainingEntriesAndGroups { JGRefreshEntityOperation *trainingGroupRefresh = [[JGRefreshEntityOperation alloc] initWithEntityName:kTrainingGroup]; NSOperationQueue *refreshQueue = [[NSOperationQueue alloc] init]; [refreshQueue setMaxConcurrentOperationCount:1]; [refreshQueue addOperation:trainingGroupRefresh]; while ([[refreshQueue operations] count] > 0) { [[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0.05]]; [windowController performSelectorOnMainThread:@selector(refreshTrainingView) withObject:nil waitUntilDone:YES]; } // JGRefreshEntityOperation.m @implementation JGRefreshEntityOperation @synthesize started; @synthesize executing; @synthesize paused; @synthesize finished; -(void)main { [self startOperation]; NSSet *allEntities = [imoc fetchAllObjectsForEntityName:entityName]; for(id thisEntity in allEntities) [imoc refreshObject:thisEntity mergeChanges:YES]; [self finishOperation]; } -(void)startOperation { [self willChangeValueForKey:@"isExecuting"]; [self willChangeValueForKey:@"isStarted"]; [self setStarted:YES]; [self setExecuting:YES]; [self didChangeValueForKey:@"isExecuting"]; [self didChangeValueForKey:@"isStarted"]; imoc = [[NSManagedObjectContext alloc] init]; [imoc setStalenessInterval:0]; [imoc setUndoManager:nil]; [imoc setPersistentStoreCoordinator:[[NSApp delegate] interpretedPSC]]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(mergeChanges:) name:NSManagedObjectContextDidSaveNotification object:imoc]; } -(void)finishOperation { saveError = nil; [imoc save:&saveError]; if (saveError) { NSLog(@"Error saving. %@", saveError); } imoc = nil; [self willChangeValueForKey:@"isExecuting"]; [self willChangeValueForKey:@"isFinished"]; [self setExecuting:NO]; [self setFinished:YES]; [self didChangeValueForKey:@"isExecuting"]; [self didChangeValueForKey:@"isFinished"]; } -(void)mergeChanges:(NSNotification *)notification { NSManagedObjectContext *mainContext = [[NSApp delegate] interpretedMOC]; [mainContext performSelectorOnMainThread:@selector(mergeChangesFromContextDidSaveNotification:) withObject:notification waitUntilDone:YES]; } -(id)initWithEntityName:(NSString *)entityName_ { [super init]; [self setStarted:false]; [self setExecuting:false]; [self setPaused:false]; [self setFinished:false]; [NSThread setThreadPriority:0.0]; entityName = entityName_; return self; } @end // JGRefreshEntityOperation.h @interface JGRefreshEntityOperation : NSOperation { NSString *entityName; NSManagedObjectContext *imoc; NSError *saveError; BOOL started; BOOL executing; BOOL paused; BOOL finished; } @property(readwrite, getter=isStarted) BOOL started; @property(readwrite, getter=isPaused) BOOL paused; @property(readwrite, getter=isExecuting) BOOL executing; @property(readwrite, getter=isFinished) BOOL finished; -(void)startOperation; -(void)finishOperation; -(id)initWithEntityName:(NSString *)entityName_; -(void)mergeChanges:(NSNotification *)notification; @end

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• Office 2010: It&rsquo;s not just DOC(X) and XLS(X)

  - by andrewbrust

  Office 2010 has released to manufacturing.  The bits have left the (product team’s) building.  Will you upgrade? This version of Office is officially numbered 14, a designation that correlates with the various releases, through the years, of Microsoft Word.  There were six major versions of Word for DOS, during whose release cycles came three 16-bit Windows versions.  Then, starting with Word 95 and counting through Word 2007, there have been six more versions – all for the 32-bit Windows platform.  Skip version 13 to ward off folksy bad luck (and, perhaps, the bugs that could come with it) and that brings us to version 14, which includes implementations for both 32- and 64-bit Windows platforms.  We’ve come a long way baby.  Or have we? As it does every three years or so, debate will now start to rage on over whether we need a “14th” version the PC platform’s standard word processor, or a “13th” version of the spreadsheet.  If you accept the premise of that question, then you may be on a slippery slope toward answering it in the negative.  Thing is, that premise is valid for certain customers and not others. The Microsoft Office product has morphed from one that offered core word processing, spreadsheet, presentation and email functionality to a suite of applications that provides unique, new value-added features, and even whole applications, in the context of those core services.  The core apps thus grow in mission: Excel is a BI tool.  Word is a collaborative editorial system for the production of publications.  PowerPoint is a media production platform for for live presentations and, increasingly, for delivering more effective presentations online.  Outlook is a time and task management system.  Access is a rich client front-end for data-driven self-service SharePoint applications.  OneNote helps you capture ideas, corral random thoughts in a semi-structured way, and then tie them back to other, more rigidly structured, Office documents. Google Docs and other cloud productivity platforms like Zoho don’t really do these things.  And there is a growing chorus of voices who say that they shouldn’t, because those ancillary capabilities are over-engineered, over-produced and “under-necessary.”  They might say Microsoft is layering on superfluous capabilities to avoid admitting that Office’s core capabilities, the ones people really need, have become commoditized. It’s hard to take sides in that argument, because different people, and the different companies that employ them, have different needs.  For my own needs, it all comes down to three basic questions: will the new version of Office save me time, will it make the mundane parts of my job easier, and will it augment my services to customers?  I need my time back.  I need to spend more of it with my family, and more of it focusing on my own core capabilities rather than the administrative tasks around them.  And I also need my customers to be able to get more value out of the services I provide. Help me triage my inbox, help me get proposals done more quickly and make them easier to read.  Let me get my presentations done faster, make them more effective and make it easier for me to reuse materials from other presentations.  And, since I’m in the BI and data business, help me and my customers manage data and analytics more easily, both on the desktop and online. Those are my criteria.  And, with those in mind, Office 2010 is looking like a worthwhile upgrade.  Perhaps it’s not earth-shattering, but it offers a combination of incremental improvements and a few new major capabilities that I think are quite compelling.  I provide a brief roundup of them here.  It’s admittedly arbitrary and not comprehensive, but I think it tells the Office 2010 story effectively. Across the Suite More than any other, this release of Office aims to give collaboration a real workout.  In certain apps, for the first time, documents can be opened simultaneously by multiple users, with colleagues’ changes appearing in near real-time.  Web-browser-based versions of Word, Excel, PowerPoint and OneNote will be available to extend collaboration to contributors who are off the corporate network. The ribbon user interface is now more pervasive (for example, it appears in OneNote and in Outlook’s main window).  It’s also customizable, allowing users to add, easily, buttons and options of their choosing, into new tabs, or into new groups within existing tabs. Microsoft has also taken the File menu (which was the “Office Button” menu in the 2007 release) and made it into a full-screen “Backstage” view where document-wide operations, like saving, printing and online publishing are performed. And because, more and more, heavily formatted content is cut and pasted between documents and applications, Office 2010 makes it easier to manage the retention or jettisoning of that formatting right as the paste operation is performed.  That’s much nicer than stripping it off, or adding it back, afterwards. And, speaking of pasting, a number of Office apps now make it especially easy to insert screenshots within their documents.  I know that’s useful to me, because I often document or critique applications and need to show them in action.  For the vast majority of users, I expect that this feature will be more useful for capturing snapshots of Web pages, but we’ll have to see whether this feature becomes popular.   Excel At first glance, Excel 2010 looks and acts nearly identically to the 2007 version.  But additional glances are necessary.  It’s important to understand that lots of people in the working world use Excel as more of a database, analytics and mathematical modeling tool than merely as a spreadsheet.  And it’s also important to understand that Excel wasn’t designed to handle such workloads past a certain scale.  That all changes with this release. The first reason things change is that Excel has been tuned for performance.  It’s been optimized for multi-threaded operation; previously lengthy processes have been shortened, especially for large data sets; more rows and columns are allowed and, for the first time, Excel (and the rest of Office) is available in a 64-bit version.  For Excel, this means users can take advantage of more than the 2GB of memory that the 32-bit version is limited to. On the analysis side, Excel 2010 adds Sparklines (tiny charts that fit into a single cell and can therefore be presented down an entire column or across a row) and Slicers (a more user-friendly filter mechanism for PivotTables and charts, which visually indicates what the filtered state of a given data member is).  But most important, Excel 2010 supports the new PowerPIvot add-in which brings true self-service BI to Office.  PowerPivot allows users to import data from almost anywhere, model it, and then analyze it.  Rather than forcing users to build “spreadmarts” or use corporate-built data warehouses, PowerPivot models function as true columnar, in-memory OLAP cubes that can accommodate millions of rows of data and deliver fast drill-down performance. And speaking of OLAP, Excel 2010 now supports an important Analysis Services OLAP feature called write-back.  Write-back is especially useful in financial forecasting scenarios for which Excel is the natural home.  Support for write-back is long overdue, but I’m still glad it’s there, because I had almost given up on it.   PowerPoint This version of PowerPoint marks its progression from a presentation tool to a video and photo editing and production tool.  Whether or not it’s successful in this pursuit, and if offering this is even a sensible goal, is another question. Regardless, the new capabilities are kind of interesting.  A greatly enhanced set of slide transitions with 3D effects; in-product photo and video editing; accommodation of embedded videos from services such as YouTube; and the ability to save a presentation as a video each lay testimony to PowerPoint’s transformation into a media tool and away from a pure presentation tool. These capabilities also recognize the importance of the Web as both a source for materials and a channel for disseminating PowerPoint output. Congruent with that is PowerPoint’s new ability to broadcast a slide presentation, using a quickly-generated public URL, without involving the hassle or expense of a Web meeting service like GoToMeeting or Microsoft’s own LiveMeeting.  Slides presented through this broadcast feature retain full color fidelity and transitions and animations are preserved as well.   Outlook Microsoft’s ubiquitous email/calendar/contact/task management tool gains long overdue speed improvements, especially against POP3 email accounts.  Outlook 2010 also supports multiple Exchange accounts, rather than just one; tighter integration with OneNote; and a new Social Connector providing integration with, and presence information from, online social network services like LinkedIn and Facebook (not to mention Windows Live).  A revamped conversation view now includes messages that are part of a given thread regardless of which folder they may be stored in. I don’t know yet how well the Social Connector will work or whether it will keep Outlook relevant to those who live on Facebook and LinkedIn.  But among the other features, there’s very little not to like.   OneNote To me, OneNote is the part of Office that just keeps getting better.  There is one major caveat to this, which I’ll cover in a moment, but let’s first catalog what new stuff OneNote 2010 brings.  The best part of OneNote, is the way each of its versions have managed hierarchy: Notebooks have sections, sections have pages, pages have sub pages, multiple notes can be contained in either, and each note supports infinite levels of indentation.  None of that is new to 2010, but the new version does make creation of pages and subpages easier and also makes simple work out of promoting and demoting pages from sub page to full page status.  And relationships between pages are quite easy to create now: much like a Wiki, simply typing a page’s name in double-square-brackets (“[[…]]”) creates a link to it. OneNote is also great at integrating content outside of its notebooks.  With a new Dock to Desktop feature, OneNote becomes aware of what window is displayed in the rest of the screen and, if it’s an Office document or a Web page, links the notes you’re typing, at the time, to it.  A single click from your notes later on will bring that same document or Web page back on-screen.  Embedding content from Web pages and elsewhere is also easier.  Using OneNote’s Windows Key+S combination to grab part of the screen now allows you to specify the destination of that bitmap instead of automatically creating a new note in the Unfiled Notes area.  Using the Send to OneNote buttons in Internet Explorer and Outlook result in the same choice. Collaboration gets better too.  Real-time multi-author editing is better accommodated and determining author lineage of particular changes is easily carried out. My one pet peeve with OneNote is the difficulty using it when I’m not one a Windows PC.  OneNote’s main competitor, Evernote, while I believe inferior in terms of features, has client versions for PC, Mac, Windows Mobile, Android, iPhone, iPad and Web browsers.  Since I have an Android phone and an iPad, I am practically forced to use it.  However, the OneNote Web app should help here, as should a forthcoming version of OneNote for Windows Phone 7.  In the mean time, it turns out that using OneNote’s Email Page ribbon button lets you move a OneNote page easily into EverNote (since every EverNote account gets a unique email address for adding notes) and that Evernote’s Email function combined with Outlook’s Send to OneNote button (in the Move group of the ribbon’s Home tab) can achieve the reverse.   Access To me, the big change in Access 2007 was its tight integration with SharePoint lists.  Access 2010 and SharePoint 2010 continue this integration with the introduction of SharePoint’s Access Services.  Much as Excel Services provides a SharePoint-hosted experience for viewing (and now editing) Excel spreadsheet, PivotTable and chart content, Access Services allows for SharePoint browser-hosted editing of Access data within the forms that are built in the Access client itself. To me this makes all kinds of sense.  Although it does beg the question of where to draw the line between Access, InfoPath, SharePoint list maintenance and SharePoint 2010’s new Business Connectivity Services.  Each of these tools provide overlapping data entry and data maintenance functionality. But if you do prefer Access, then you’ll like  things like templates and application parts that make it easier to get off the blank page.  These features help you quickly get tables, forms and reports built out.  To make things look nice, Access even gets its own version of Excel’s Conditional Formatting feature, letting you add data bars and data-driven text formatting.   Word As I said at the beginning of this post, upgrades to Office are about much more than enhancing the suite’s flagship word processing application. So are there any enhancements in Word worth mentioning?  I think so.  The most important one has to be the collaboration features.  Essentially, when a user opens a Word document that is in a SharePoint document library (or Windows Live SkyDrive folder), rather than the whole document being locked, Word has the ability to observe more granular locks on the individual paragraphs being edited.  Word also shows you who’s editing what and its Save function morphs into a sync feature that both saves your changes and loads those made by anyone editing the document concurrently. There’s also a new navigation pane that lets you manage sections in your document in much the same way as you manage slides in a PowerPoint deck.  Using the navigation pane, you can reorder sections, insert new ones, or promote and demote sections in the outline hierarchy.  Not earth shattering, but nice.   Other Apps and Summarized Findings What about InfoPath, Publisher, Visio and Project?  I haven’t looked at them yet.  And for this post, I think that’s fine.  While those apps (and, arguably, Access) cater to specific tasks, I think the apps we’ve looked at in this post service the general purpose needs of most users.  And the theme in those 2010 apps is clear: collaboration is key, the Web and productivity are indivisible, and making data and analytics into a self-service amenity is the way to go.  But perhaps most of all, features are still important, as long as they get you through your day faster, rather than adding complexity for its own sake.  I would argue that this is true for just about every product Microsoft makes: users want utility, not complexity.

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• C#/.NET Little Wonders: Interlocked CompareExchange()

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Two posts ago, I discussed the Interlocked Add(), Increment(), and Decrement() methods (here) for adding and subtracting values in a thread-safe, lightweight manner.  Then, last post I talked about the Interlocked Read() and Exchange() methods (here) for safely and efficiently reading and setting 32 or 64 bit values (or references).  This week, we’ll round out the discussion by talking about the Interlocked CompareExchange() method and how it can be put to use to exchange a value if the current value is what you expected it to be. Dirty reads can lead to bad results Many of the uses of Interlocked that we’ve explored so far have centered around either reading, setting, or adding values.  But what happens if you want to do something more complex such as setting a value based on the previous value in some manner? Perhaps you were creating an application that reads a current balance, applies a deposit, and then saves the new modified balance, where of course you’d want that to happen atomically.  If you read the balance, then go to save the new balance and between that time the previous balance has already changed, you’ll have an issue!  Think about it, if we read the current balance as $400, and we are applying a new deposit of $50.75, but meanwhile someone else deposits $200 and sets the total to $600, but then we write a total of $450.75 we’ve lost $200! Now, certainly for int and long values we can use Interlocked.Add() to handles these cases, and it works well for that.  But what if we want to work with doubles, for example?  Let’s say we wanted to add the numbers from 0 to 99,999 in parallel.  We could do this by spawning several parallel tasks to continuously add to a total: 1: double total = 0; 2:  3: Parallel.For(0, 10000, next => 4: { 5: total += next; 6: }); Were this run on one thread using a standard for loop, we’d expect an answer of 4,999,950,000 (the sum of all numbers from 0 to 99,999).  But when we run this in parallel as written above, we’ll likely get something far off.  The result of one of my runs, for example, was 1,281,880,740.  That is way off!  If this were banking software we’d be in big trouble with our clients.  So what happened?  The += operator is not atomic, it will read in the current value, add the result, then store it back into the total.  At any point in all of this another thread could read a “dirty” current total and accidentally “skip” our add.   So, to clean this up, we could use a lock to guarantee concurrency: 1: double total = 0.0; 2: object locker = new object(); 3:  4: Parallel.For(0, count, next => 5: { 6: lock (locker) 7: { 8: total += next; 9: } 10: }); Which will give us the correct result of 4,999,950,000.  One thing to note is that locking can be heavy, especially if the operation being locked over is trivial, or the life of the lock is a high percentage of the work being performed concurrently.  In the case above, the lock consumes pretty much all of the time of each parallel task – and the task being locked on is relatively trivial. Now, let me put in a disclaimer here before we go further: For most uses, lock is more than sufficient for your needs, and is often the simplest solution!    So, if lock is sufficient for most needs, why would we ever consider another solution?  The problem with locking is that it can suspend execution of your thread while it waits for the signal that the lock is free.  Moreover, if the operation being locked over is trivial, the lock can add a very high level of overhead.  This is why things like Interlocked.Increment() perform so well, instead of locking just to perform an increment, we perform the increment with an atomic, lockless method. As with all things performance related, it’s important to profile before jumping to the conclusion that you should optimize everything in your path.  If your profiling shows that locking is causing a high level of waiting in your application, then it’s time to consider lighter alternatives such as Interlocked. CompareExchange() – Exchange existing value if equal some value So let’s look at how we could use CompareExchange() to solve our problem above.  The general syntax of CompareExchange() is: T CompareExchange<T>(ref T location, T newValue, T expectedValue) If the value in location == expectedValue, then newValue is exchanged.  Either way, the value in location (before exchange) is returned. Actually, CompareExchange() is not one method, but a family of overloaded methods that can take int, long, float, double, pointers, or references.  It cannot take other value types (that is, can’t CompareExchange() two DateTime instances directly).  Also keep in mind that the version that takes any reference type (the generic overload) only checks for reference equality, it does not call any overridden Equals(). So how does this help us?  Well, we can grab the current total, and exchange the new value if total hasn’t changed.  This would look like this: 1: // grab the snapshot 2: double current = total; 3:  4: // if the total hasn’t changed since I grabbed the snapshot, then 5: // set it to the new total 6: Interlocked.CompareExchange(ref total, current + next, current); So what the code above says is: if the amount in total (1st arg) is the same as the amount in current (3rd arg), then set total to current + next (2nd arg).  This check and exchange pair is atomic (and thus thread-safe). This works if total is the same as our snapshot in current, but the problem, is what happens if they aren’t the same?  Well, we know that in either case we will get the previous value of total (before the exchange), back as a result.  Thus, we can test this against our snapshot to see if it was the value we expected: 1: // if the value returned is != current, then our snapshot must be out of date 2: // which means we didn't (and shouldn't) apply current + next 3: if (Interlocked.CompareExchange(ref total, current + next, current) != current) 4: { 5: // ooops, total was not equal to our snapshot in current, what should we do??? 6: } So what do we do if we fail?  That’s up to you and the problem you are trying to solve.  It’s possible you would decide to abort the whole transaction, or perhaps do a lightweight spin and try again.  Let’s try that: 1: double current = total; 2:  3: // make first attempt... 4: if (Interlocked.CompareExchange(ref total, current + i, current) != current) 5: { 6: // if we fail, go into a spin wait, spin, and try again until succeed 7: var spinner = new SpinWait(); 8:  9: do 10: { 11: spinner.SpinOnce(); 12: current = total; 13: } 14: while (Interlocked.CompareExchange(ref total, current + i, current) != current); 15: } 16:  This is not trivial code, but it illustrates a possible use of CompareExchange().  What we are doing is first checking to see if we succeed on the first try, and if so great!  If not, we create a SpinWait and then repeat the process of SpinOnce(), grab a fresh snapshot, and repeat until CompareExchnage() succeeds.  You may wonder why not a simple do-while here, and the reason it’s more efficient to only create the SpinWait until we absolutely know we need one, for optimal efficiency. Though not as simple (or maintainable) as a simple lock, this will perform better in many situations.  Comparing an unlocked (and wrong) version, a version using lock, and the Interlocked of the code, we get the following average times for multiple iterations of adding the sum of 100,000 numbers: 1: Unlocked money average time: 2.1 ms 2: Locked money average time: 5.1 ms 3: Interlocked money average time: 3 ms So the Interlocked.CompareExchange(), while heavier to code, came in lighter than the lock, offering a good compromise of safety and performance when we need to reduce contention. CompareExchange() - it’s not just for adding stuff… So that was one simple use of CompareExchange() in the context of adding double values -- which meant we couldn’t have used the simpler Interlocked.Add() -- but it has other uses as well. If you think about it, this really works anytime you want to create something new based on a current value without using a full lock.  For example, you could use it to create a simple lazy instantiation implementation.  In this case, we want to set the lazy instance only if the previous value was null: 1: public static class Lazy<T> where T : class, new() 2: { 3: private static T _instance; 4:  5: public static T Instance 6: { 7: get 8: { 9: // if current is null, we need to create new instance 10: if (_instance == null) 11: { 12: // attempt create, it will only set if previous was null 13: Interlocked.CompareExchange(ref _instance, new T(), (T)null); 14: } 15:  16: return _instance; 17: } 18: } 19: } So, if _instance == null, this will create a new T() and attempt to exchange it with _instance.  If _instance is not null, then it does nothing and we discard the new T() we created. This is a way to create lazy instances of a type where we are more concerned about locking overhead than creating an accidental duplicate which is not used.  In fact, the BCL implementation of Lazy<T> offers a similar thread-safety choice for Publication thread safety, where it will not guarantee only one instance was created, but it will guarantee that all readers get the same instance.  Another possible use would be in concurrent collections.  Let’s say, for example, that you are creating your own brand new super stack that uses a linked list paradigm and is “lock free”.  We could use Interlocked.CompareExchange() to be able to do a lockless Push() which could be more efficient in multi-threaded applications where several threads are pushing and popping on the stack concurrently. Yes, there are already concurrent collections in the BCL (in .NET 4.0 as part of the TPL), but it’s a fun exercise!  So let’s assume we have a node like this: 1: public sealed class Node<T> 2: { 3: // the data for this node 4: public T Data { get; set; } 5:  6: // the link to the next instance 7: internal Node<T> Next { get; set; } 8: } Then, perhaps, our stack’s Push() operation might look something like: 1: public sealed class SuperStack<T> 2: { 3: private volatile T _head; 4:  5: public void Push(T value) 6: { 7: var newNode = new Node<int> { Data = value, Next = _head }; 8:  9: if (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next) 10: { 11: var spinner = new SpinWait(); 12:  13: do 14: { 15: spinner.SpinOnce(); 16: newNode.Next = _head; 17: } 18: while (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next); 19: } 20: } 21:  22: // ... 23: } Notice a similar paradigm here as with adding our doubles before.  What we are doing is creating the new Node with the data to push, and with a Next value being the original node referenced by _head.  This will create our stack behavior (LIFO – Last In, First Out).  Now, we have to set _head to now refer to the newNode, but we must first make sure it hasn’t changed! So we check to see if _head has the same value we saved in our snapshot as newNode.Next, and if so, we set _head to newNode.  This is all done atomically, and the result is _head’s original value, as long as the original value was what we assumed it was with newNode.Next, then we are good and we set it without a lock!  If not, we SpinWait and try again. Once again, this is much lighter than locking in highly parallelized code with lots of contention.  If I compare the method above with a similar class using lock, I get the following results for pushing 100,000 items: 1: Locked SuperStack average time: 6 ms 2: Interlocked SuperStack average time: 4.5 ms So, once again, we can get more efficient than a lock, though there is the cost of added code complexity.  Fortunately for you, most of the concurrent collection you’d ever need are already created for you in the System.Collections.Concurrent (here) namespace – for more information, see my Little Wonders – The Concurent Collections Part 1 (here), Part 2 (here), and Part 3 (here). Summary We’ve seen before how the Interlocked class can be used to safely and efficiently add, increment, decrement, read, and exchange values in a multi-threaded environment.  In addition to these, Interlocked CompareExchange() can be used to perform more complex logic without the need of a lock when lock contention is a concern. The added efficiency, though, comes at the cost of more complex code.  As such, the standard lock is often sufficient for most thread-safety needs.  But if profiling indicates you spend a lot of time waiting for locks, or if you just need a lock for something simple such as an increment, decrement, read, exchange, etc., then consider using the Interlocked class’s methods to reduce wait. Technorati Tags: C#,CSharp,.NET,Little Wonders,Interlocked,CompareExchange,threading,concurrency

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• Why are my Opteron cores running at only 75% capacity each? (25% CPU idle)

  - by Tim Cooper

  We've just taken delivery of a powerful 32-core AMD Opteron server with 128Gb. We have 2 x 6272 CPU's with 16 cores each. We are running a big long-running java task on 30 threads. We have the NUMA optimisations for Linux and java turned on. Our Java threads are mainly using objects that are private to that thread, sometimes reading memory that other threads will be reading, and very very occasionally writing or locking shared objects. We can't explain why the CPU cores are 25% idle. Below is a dump of "top": top - 23:06:38 up 1 day, 23 min, 3 users, load average: 10.84, 10.27, 9.62 Tasks: 676 total, 1 running, 675 sleeping, 0 stopped, 0 zombie Cpu(s): 64.5%us, 1.3%sy, 0.0%ni, 32.9%id, 1.3%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 132138168k total, 131652664k used, 485504k free, 92340k buffers Swap: 5701624k total, 230252k used, 5471372k free, 13444344k cached ... top - 22:37:39 up 23:54, 3 users, load average: 7.83, 8.70, 9.27 Tasks: 678 total, 1 running, 677 sleeping, 0 stopped, 0 zombie Cpu0 : 75.8%us, 2.0%sy, 0.0%ni, 22.2%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu1 : 77.2%us, 1.3%sy, 0.0%ni, 21.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu2 : 77.3%us, 1.0%sy, 0.0%ni, 21.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu3 : 77.8%us, 1.0%sy, 0.0%ni, 21.2%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu4 : 76.9%us, 2.0%sy, 0.0%ni, 21.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu5 : 76.3%us, 2.0%sy, 0.0%ni, 21.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu6 : 12.6%us, 3.0%sy, 0.0%ni, 84.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu7 : 8.6%us, 2.0%sy, 0.0%ni, 89.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu8 : 77.0%us, 2.0%sy, 0.0%ni, 21.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu9 : 77.0%us, 2.0%sy, 0.0%ni, 21.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu10 : 77.6%us, 1.7%sy, 0.0%ni, 20.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu11 : 75.7%us, 2.0%sy, 0.0%ni, 21.4%id, 1.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu12 : 76.6%us, 2.3%sy, 0.0%ni, 21.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu13 : 76.6%us, 2.3%sy, 0.0%ni, 21.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu14 : 76.2%us, 2.6%sy, 0.0%ni, 15.9%id, 5.3%wa, 0.0%hi, 0.0%si, 0.0%st Cpu15 : 76.6%us, 2.0%sy, 0.0%ni, 21.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu16 : 73.6%us, 2.6%sy, 0.0%ni, 23.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu17 : 74.5%us, 2.3%sy, 0.0%ni, 23.2%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu18 : 73.9%us, 2.3%sy, 0.0%ni, 23.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu19 : 72.9%us, 2.6%sy, 0.0%ni, 24.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu20 : 72.8%us, 2.6%sy, 0.0%ni, 24.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu21 : 72.7%us, 2.3%sy, 0.0%ni, 25.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu22 : 72.5%us, 2.6%sy, 0.0%ni, 24.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu23 : 73.0%us, 2.3%sy, 0.0%ni, 24.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu24 : 74.7%us, 2.7%sy, 0.0%ni, 22.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu25 : 74.5%us, 2.6%sy, 0.0%ni, 22.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu26 : 73.7%us, 2.0%sy, 0.0%ni, 24.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu27 : 74.1%us, 2.3%sy, 0.0%ni, 23.6%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu28 : 74.1%us, 2.3%sy, 0.0%ni, 23.6%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu29 : 74.0%us, 2.0%sy, 0.0%ni, 24.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu30 : 73.2%us, 2.3%sy, 0.0%ni, 24.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu31 : 73.1%us, 2.0%sy, 0.0%ni, 24.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 132138168k total, 131711704k used, 426464k free, 88336k buffers Swap: 5701624k total, 229572k used, 5472052k free, 13745596k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 13865 root 20 0 122g 112g 3.1g S 2334.3 89.6 20726:49 java 27139 jayen 20 0 15428 1728 952 S 2.6 0.0 0:04.21 top 27161 sysadmin 20 0 15428 1712 940 R 1.0 0.0 0:00.28 top 33 root 20 0 0 0 0 S 0.3 0.0 0:06.24 ksoftirqd/7 131 root 20 0 0 0 0 S 0.3 0.0 0:09.52 events/0 1858 root 20 0 0 0 0 S 0.3 0.0 1:35.14 kondemand/0 A dump of the java stack confirms that none of the threads are anywhere near the few places where locks are used, nor are they anywhere near any disk or network i/o. I had trouble finding a clear explanation of what 'top' means by "idle" versus "wait", but I get the impression that "idle" means "no more threads that need to be run" but this doesn't make sense in our case. We're using a "Executors.newFixedThreadPool(30)". There are a large number of tasks pending and each task lasts for 10 seconds or so. I suspect that the explanation requires a good understanding of NUMA. Is the "idle" state what you see when a CPU is waiting for a non-local access? If not, then what is the explanation?

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• Yet another C# Deadlock Debugging Question

  - by Roo

  Hi All, I have a multi-threaded application build in C# using VS2010 Professional. It's quite a large application and we've experienced the classing GUI cross-threading and deadlock issues before, but in the past month we've noticed the appears to lock up when left idle for around 20-30 minutes. The application is irresponsive and although it will repaint itself when other windows are dragged in front of the application and over it, the GUI still appears to be locked... interstingly (unlike if the GUI thread is being used for a considerable amount of time) the Close, Maximise and minimise buttons are also irresponsive and when clicked the little (Not Responding...) text is not displayed in the title of the application i.e. Windows still seems to think it's running fine. If I break/pause the application using the debugger, and view the threads that are running. There are 3 threads of our managed code that are running, and a few other worker threads whom the source code cannot be displayed for. The 3 threads that run are: The main/GUI thread A thread that loops indefinitely A thread that loops indefinitely If I step into threads 2 and 3, they appear to be looping correctly. They do not share locks (even with the main GUI thread) and they are not using the GUI thread at all. When stepping into the main/GUI thread however, it's broken on Application.Run... This problem screams deadlock to me, but what I don't understand is if it's deadlock, why can't I see the line of code the main/GUI thread is hanging on? Any help will be greatly appreciated! Let me know if you need more information... Cheers, Roo -----------------------------------------------------SOLUTION-------------------------------------------------- Okay, so the problem is now solved. Thanks to everyone for their suggestions! Much appreciated! I've marked the answer that solved my initial problem of determining where on the main/UI thread the application hangs (I handn't turned off the "Enable Just My Code" option). The overall issue I was experiencing was indeed Deadlock, however. After obtaining the call-stack and popping the top half of it into Google I came across this which explains exactly what I was experiencing... http://timl.net/ This references a lovely guide to debugging the issue... http://www.aaronlerch.com/blog/2008/12/15/debugging-ui/ This identified a control I was constructing off the GUI thread. I did know this, however, and was marshalling calls correctly, but what I didn't realise was that behind the scenes this Control was subscribing to an event or set of events that are triggered when e.g. a Windows session is unlocked or the screensaver exits. These calls are always made on the main/UI thread and were blocking when it saw the call was made on the incorrect thread. Kim explains in more detail here... http://krgreenlee.blogspot.com/2007/09/onuserpreferencechanged-hang.html In the end I found an alternative solution which did not require this Control off the main/UI thread. That appears to have solved the problem and the application no longer hangs. I hope this helps anyone who's confronted by a similar problem. Thanks again to everyone on here who helped! (and indirectly, the delightful bloggers I've referenced above!) Roo -----------------------------------------------------SOLUTION II-------------------------------------------------- Aren't threading issues delightful...you think you've solved it, and a month down the line it pops back up again. I still believe the solution above resolved an issue that would cause simillar behaviour, but we encountered the problem again. As we spent a while debugging this, I thought I'd update this question with our (hopefully) final solution: The problem appears to have been a bug in the Infragistics components in the WinForms 2010.1 release (no hot fixes). We had been running from around the time the freeze issue appeared (but had also added a bunch of other stuff too). After upgrading to WinForms 2010.3, we've yet to reproduce the issue (deja vu). See my question here for a bit more information: 'http://stackoverflow.com/questions/4077822/net-4-0-and-the-dreaded-onuserpreferencechanged-hang'. Hans has given a nice summary of the general issue. I hope this adds a little to the suggestions/information surrounding the nutorious OnUserPreferenceChanged Hang (or whatever you'd like to call it). Cheers, Roo

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• How should I store Dynamically Changing Data into Server Cache?

  - by Scott

  Hey all, EDIT: Purpose of this Website: Its called Utopiapimp.com. It is a third party utility for a game called utopia-game.com. The site currently has over 12k users to it an I run the site. The game is fully text based and will always remain that. Users copy and paste full pages of text from the game and paste the copied information into my site. I run a series of regular expressions against the pasted data and break it down. I then insert anywhere from 5 values to over 30 values into the DB based on that one paste. I then take those values and run queries against them to display the information back in a VERY simple and easy to understand way. The game is team based and each team has 25 users to it. So each team is a group and each row is ONE users information. The users can update all 25 rows or just one row at a time. I require storing things into cache because the site is very slow doing over 1,000 queries almost every minute. So here is the deal. Imagine I have an excel spreadsheet with 100 columns and 5000 rows. Each row has two unique identifiers. One for the row it self and one to group together 25 rows a piece. There are about 10 columns in the row that will almost never change and the other 90 columns will always be changing. We can say some will even change in a matter of seconds depending on how fast the row is updated. Rows can also be added and deleted from the group, but not from the database. The rows are taken from about 4 queries from the database to show the most recent and updated data from the database. So every time something in the database is updated, I would also like the row to be updated. If a row or a group has not been updated in 12 or so hours, it will be taken out of Cache. Once the user calls the group again via the DB queries. They will be placed into Cache. The above is what I would like. That is the wish. In Reality, I still have all the rows, but the way I store them in Cache is currently broken. I store each row in a class and the class is stored in the Server Cache via a HUGE list. When I go to update/Delete/Insert items in the list or rows, most the time it works, but sometimes it throws errors because the cache has changed. I want to be able to lock down the cache like the database throws a lock on a row more or less. I have DateTime stamps to remove things after 12 hours, but this almost always breaks because other users are updating the same 25 rows in the group or just the cache has changed. This is an example of how I add items to Cache, this one shows I only pull the 10 or so columns that very rarely change. This example all removes rows not updated after 12 hours: DateTime dt = DateTime.UtcNow; if (HttpContext.Current.Cache["GetRows"] != null) { List<RowIdentifiers> pis = (List<RowIdentifiers>)HttpContext.Current.Cache["GetRows"]; var ch = (from xx in pis where xx.groupID == groupID where xx.rowID== rowID select xx).ToList(); if (ch.Count() == 0) { var ck = GetInGroupNotCached(rowID, groupID, dt); //Pulling the group from the DB for (int i = 0; i < ck.Count(); i++) pis.Add(ck[i]); pis.RemoveAll((x) => x.updateDateTime < dt.AddHours(-12)); HttpContext.Current.Cache["GetRows"] = pis; return ck; } else return ch; } else { var pis = GetInGroupNotCached(rowID, groupID, dt);//Pulling the group from the DB HttpContext.Current.Cache["GetRows"] = pis; return pis; } On the last point, I remove items from the cache, so the cache doesn't actually get huge. To re-post the question, Whats a better way of doing this? Maybe and how to put locks on the cache? Can I get better than this? I just want it to stop breaking when removing or adding rows.

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• Configuring OpenLDAP and SSL

  - by Stormshadow

  I am having trouble trying to connect to a secure OpenLDAP server which I have set up. On running my LDAP client code java -Djavax.net.debug=ssl LDAPConnector I get the following exception trace (java version 1.6.0_17) trigger seeding of SecureRandom done seeding SecureRandom %% No cached client session *** ClientHello, TLSv1 RandomCookie: GMT: 1256110124 bytes = { 224, 19, 193, 148, 45, 205, 108, 37, 101, 247, 112, 24, 157, 39, 111, 177, 43, 53, 206, 224, 68, 165, 55, 185, 54, 203, 43, 91 } Session ID: {} Cipher Suites: [SSL_RSA_WITH_RC4_128_MD5, SSL_RSA_WITH_RC4_128_SHA, TLS_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_DSS_WITH_AES_128_CBC_SHA, SSL_RSA_W ITH_3DES_EDE_CBC_SHA, SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA, SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA, SSL_RSA_WITH_DES_CBC_SHA, SSL_DHE_RSA_WITH_DES_CBC_SHA, SSL_DHE_DSS_WITH_DES_CBC_SH A, SSL_RSA_EXPORT_WITH_RC4_40_MD5, SSL_RSA_EXPORT_WITH_DES40_CBC_SHA, SSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA, SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA] Compression Methods: { 0 } *** Thread-0, WRITE: TLSv1 Handshake, length = 73 Thread-0, WRITE: SSLv2 client hello message, length = 98 Thread-0, received EOFException: error Thread-0, handling exception: javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake Thread-0, SEND TLSv1 ALERT: fatal, description = handshake_failure Thread-0, WRITE: TLSv1 Alert, length = 2 Thread-0, called closeSocket() main, handling exception: javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake javax.naming.CommunicationException: simple bind failed: ldap.natraj.com:636 [Root exception is javax.net.ssl.SSLHandshakeException: Remote host closed connection during hands hake] at com.sun.jndi.ldap.LdapClient.authenticate(Unknown Source) at com.sun.jndi.ldap.LdapCtx.connect(Unknown Source) at com.sun.jndi.ldap.LdapCtx.<init>(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getUsingURL(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getUsingURLs(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxInstance(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getInitialContext(Unknown Source) at javax.naming.spi.NamingManager.getInitialContext(Unknown Source) at javax.naming.InitialContext.getDefaultInitCtx(Unknown Source) at javax.naming.InitialContext.init(Unknown Source) at javax.naming.InitialContext.<init>(Unknown Source) at javax.naming.directory.InitialDirContext.<init>(Unknown Source) at LDAPConnector.CallSecureLDAPServer(LDAPConnector.java:43) at LDAPConnector.main(LDAPConnector.java:237) Caused by: javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(Unknown Source) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readDataRecord(Unknown Source) at com.sun.net.ssl.internal.ssl.AppInputStream.read(Unknown Source) at java.io.BufferedInputStream.fill(Unknown Source) at java.io.BufferedInputStream.read1(Unknown Source) at java.io.BufferedInputStream.read(Unknown Source) at com.sun.jndi.ldap.Connection.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.io.EOFException: SSL peer shut down incorrectly at com.sun.net.ssl.internal.ssl.InputRecord.read(Unknown Source) ... 9 more I am able to connect to the same secure LDAP server however if I use another version of java (1.6.0_14) I have created and installed the server certificates in the cacerts of both the JRE's as mentioned in this guide -- OpenLDAP with SSL When I run ldapsearch -x on the server I get # extended LDIF # # LDAPv3 # base <dc=localdomain> (default) with scope subtree # filter: (objectclass=*) # requesting: ALL # # localdomain dn: dc=localdomain objectClass: top objectClass: dcObject objectClass: organization o: localdomain dc: localdomain # admin, localdomain dn: cn=admin,dc=localdomain objectClass: simpleSecurityObject objectClass: organizationalRole cn: admin description: LDAP administrator # search result search: 2 result: 0 Success # numResponses: 3 # numEntries: 2 On running openssl s_client -connect ldap.natraj.com:636 -showcerts , I obtain the self signed certificate. My slapd.conf file is as follows ####################################################################### # Global Directives: # Features to permit #allow bind_v2 # Schema and objectClass definitions include /etc/ldap/schema/core.schema include /etc/ldap/schema/cosine.schema include /etc/ldap/schema/nis.schema include /etc/ldap/schema/inetorgperson.schema # Where the pid file is put. The init.d script # will not stop the server if you change this. pidfile /var/run/slapd/slapd.pid # List of arguments that were passed to the server argsfile /var/run/slapd/slapd.args # Read slapd.conf(5) for possible values loglevel none # Where the dynamically loaded modules are stored modulepath /usr/lib/ldap moduleload back_hdb # The maximum number of entries that is returned for a search operation sizelimit 500 # The tool-threads parameter sets the actual amount of cpu's that is used # for indexing. tool-threads 1 ####################################################################### # Specific Backend Directives for hdb: # Backend specific directives apply to this backend until another # 'backend' directive occurs backend hdb ####################################################################### # Specific Backend Directives for 'other': # Backend specific directives apply to this backend until another # 'backend' directive occurs #backend <other> ####################################################################### # Specific Directives for database #1, of type hdb: # Database specific directives apply to this databasse until another # 'database' directive occurs database hdb # The base of your directory in database #1 suffix "dc=localdomain" # rootdn directive for specifying a superuser on the database. This is needed # for syncrepl. rootdn "cn=admin,dc=localdomain" # Where the database file are physically stored for database #1 directory "/var/lib/ldap" # The dbconfig settings are used to generate a DB_CONFIG file the first # time slapd starts. They do NOT override existing an existing DB_CONFIG # file. You should therefore change these settings in DB_CONFIG directly # or remove DB_CONFIG and restart slapd for changes to take effect. # For the Debian package we use 2MB as default but be sure to update this # value if you have plenty of RAM dbconfig set_cachesize 0 2097152 0 # Sven Hartge reported that he had to set this value incredibly high # to get slapd running at all. See http://bugs.debian.org/303057 for more # information. # Number of objects that can be locked at the same time. dbconfig set_lk_max_objects 1500 # Number of locks (both requested and granted) dbconfig set_lk_max_locks 1500 # Number of lockers dbconfig set_lk_max_lockers 1500 # Indexing options for database #1 index objectClass eq # Save the time that the entry gets modified, for database #1 lastmod on # Checkpoint the BerkeleyDB database periodically in case of system # failure and to speed slapd shutdown. checkpoint 512 30 # Where to store the replica logs for database #1 # replogfile /var/lib/ldap/replog # The userPassword by default can be changed # by the entry owning it if they are authenticated. # Others should not be able to see it, except the # admin entry below # These access lines apply to database #1 only access to attrs=userPassword,shadowLastChange by dn="cn=admin,dc=localdomain" write by anonymous auth by self write by * none # Ensure read access to the base for things like # supportedSASLMechanisms. Without this you may # have problems with SASL not knowing what # mechanisms are available and the like. # Note that this is covered by the 'access to *' # ACL below too but if you change that as people # are wont to do you'll still need this if you # want SASL (and possible other things) to work # happily. access to dn.base="" by * read # The admin dn has full write access, everyone else # can read everything. access to * by dn="cn=admin,dc=localdomain" write by * read # For Netscape Roaming support, each user gets a roaming # profile for which they have write access to #access to dn=".*,ou=Roaming,o=morsnet" # by dn="cn=admin,dc=localdomain" write # by dnattr=owner write ####################################################################### # Specific Directives for database #2, of type 'other' (can be hdb too): # Database specific directives apply to this databasse until another # 'database' directive occurs #database <other> # The base of your directory for database #2 #suffix "dc=debian,dc=org" ####################################################################### # SSL: # Uncomment the following lines to enable SSL and use the default # snakeoil certificates. #TLSCertificateFile /etc/ssl/certs/ssl-cert-snakeoil.pem #TLSCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key TLSCipherSuite TLS_RSA_AES_256_CBC_SHA TLSCACertificateFile /etc/ldap/ssl/server.pem TLSCertificateFile /etc/ldap/ssl/server.pem TLSCertificateKeyFile /etc/ldap/ssl/server.pem My ldap.conf file is # # LDAP Defaults # # See ldap.conf(5) for details # This file should be world readable but not world writable. HOST ldap.natraj.com PORT 636 BASE dc=localdomain URI ldaps://ldap.natraj.com TLS_CACERT /etc/ldap/ssl/server.pem TLS_REQCERT allow #SIZELIMIT 12 #TIMELIMIT 15 #DEREF never Why is it that I can connect to the same server using one version of JRE while I cannot with another ?

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• Why does my laptop resume immediately after suspend?

  - by Igor Zinov'yev

  I seem to be having some problem with suspend mode. Every time I try to suspend my laptop, it just locks the screen. Or maybe it successfully suspends just to resume only an instant after. What could cause such a behaviour? I'm running 32-bit Ubuntu 12.04 with the 3.2.0-25 kernel on a HP dv5-1178er Pavilion laptop (Intel Core 2 Duo). Here are the relevant log sections: kern.log: Jun 1 10:42:21 igor-laptop kernel: [ 2225.131171] PM: Syncing filesystems ... done. Jun 1 10:42:21 igor-laptop kernel: [ 2225.141222] PM: Preparing system for mem sleep Jun 1 10:42:21 igor-laptop kernel: [ 2225.141239] Freezing user space processes ... (elapsed 0.01 seconds) done. Jun 1 10:42:21 igor-laptop kernel: [ 2225.156171] Freezing remaining freezable tasks ... (elapsed 0.01 seconds) done. Jun 1 10:42:21 igor-laptop kernel: [ 2225.172139] PM: Entering mem sleep Jun 1 10:42:21 igor-laptop kernel: [ 2225.172169] Suspending console(s) (use no_console_suspend to debug) Jun 1 10:42:21 igor-laptop kernel: [ 2225.172895] sd 0:0:0:0: [sda] Synchronizing SCSI cache Jun 1 10:42:21 igor-laptop kernel: [ 2225.181767] sd 0:0:0:0: [sda] Stopping disk Jun 1 10:42:21 igor-laptop kernel: [ 2225.251089] ene_ir 00:0a: wake-up capability enabled by ACPI Jun 1 10:42:21 igor-laptop kernel: [ 2225.251115] i8042 aux 00:09: wake-up capability disabled by ACPI Jun 1 10:42:21 igor-laptop kernel: [ 2225.251133] i8042 kbd 00:08: wake-up capability enabled by ACPI Jun 1 10:42:21 igor-laptop kernel: [ 2225.251286] jmb38x_ms 0000:06:00.3: PCI INT A disabled Jun 1 10:42:21 igor-laptop kernel: [ 2225.252491] sdhci-pci 0000:06:00.1: PCI INT A disabled Jun 1 10:42:21 igor-laptop kernel: [ 2225.264130] uhci_hcd 0000:00:1d.2: PCI INT D disabled Jun 1 10:42:21 igor-laptop kernel: [ 2225.264142] uhci_hcd 0000:00:1d.1: PCI INT B disabled Jun 1 10:42:21 igor-laptop kernel: [ 2225.264325] uhci_hcd 0000:00:1a.1: PCI INT B disabled Jun 1 10:42:21 igor-laptop kernel: [ 2225.288059] uhci_hcd 0000:00:1a.0: PCI INT A disabled Jun 1 10:42:21 igor-laptop kernel: [ 2225.288097] uhci_hcd 0000:00:1d.3: PCI INT C disabled Jun 1 10:42:21 igor-laptop kernel: [ 2225.288135] uhci_hcd 0000:00:1d.0: PCI INT A disabled Jun 1 10:42:21 igor-laptop kernel: [ 2225.316051] ehci_hcd 0000:00:1d.7: PCI INT A disabled Jun 1 10:42:21 igor-laptop kernel: [ 2225.316068] ehci_hcd 0000:00:1a.7: PCI INT D disabled Jun 1 10:42:21 igor-laptop kernel: [ 2225.522872] PM: suspend of drv:sd dev:0:0:0:0 complete after 349.979 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.522901] PM: suspend of drv:scsi dev:target0:0:0 complete after 349.955 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.522927] PM: suspend of drv:scsi dev:host0 complete after 272.260 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.522969] ahci 0000:00:1f.2: BIOS update required for suspend/resume Jun 1 10:42:21 igor-laptop kernel: [ 2225.522976] pci_legacy_suspend(): ahci_pci_device_suspend+0x0/0x80 returns -5 Jun 1 10:42:21 igor-laptop kernel: [ 2225.522981] pm_op(): pci_pm_suspend+0x0/0x110 returns -5 Jun 1 10:42:21 igor-laptop kernel: [ 2225.522984] PM: suspend of drv:ahci dev:0000:00:1f.2 complete after 258.932 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.522987] PM: Device 0000:00:1f.2 failed to suspend async: error -5 Jun 1 10:42:21 igor-laptop kernel: [ 2225.576228] snd_hda_intel 0000:00:1b.0: PCI INT A disabled Jun 1 10:42:21 igor-laptop kernel: [ 2225.576270] ACPI handle has no context! Jun 1 10:42:21 igor-laptop kernel: [ 2225.592136] PM: suspend of drv:snd_hda_intel dev:0000:00:1b.0 complete after 327.889 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.592206] PM: Some devices failed to suspend Jun 1 10:42:21 igor-laptop kernel: [ 2225.592291] uhci_hcd 0000:00:1a.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592298] uhci_hcd 0000:00:1a.0: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592325] usb usb3: root hub lost power or was reset Jun 1 10:42:21 igor-laptop kernel: [ 2225.592339] uhci_hcd 0000:00:1a.1: PCI INT B -> GSI 21 (level, low) -> IRQ 21 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592345] uhci_hcd 0000:00:1a.1: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592371] usb usb4: root hub lost power or was reset Jun 1 10:42:21 igor-laptop kernel: [ 2225.592387] ehci_hcd 0000:00:1a.7: PCI INT D -> GSI 19 (level, low) -> IRQ 19 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592395] ehci_hcd 0000:00:1a.7: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592843] uhci_hcd 0000:00:1d.0: PCI INT A -> GSI 20 (level, low) -> IRQ 20 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592851] uhci_hcd 0000:00:1d.0: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592854] uhci_hcd 0000:00:1d.1: PCI INT B -> GSI 19 (level, low) -> IRQ 19 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592863] uhci_hcd 0000:00:1d.1: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592878] usb usb5: root hub lost power or was reset Jun 1 10:42:21 igor-laptop kernel: [ 2225.592892] usb usb6: root hub lost power or was reset Jun 1 10:42:21 igor-laptop kernel: [ 2225.592895] uhci_hcd 0000:00:1d.2: PCI INT D -> GSI 16 (level, low) -> IRQ 16 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592903] uhci_hcd 0000:00:1d.2: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592906] uhci_hcd 0000:00:1d.3: PCI INT C -> GSI 18 (level, low) -> IRQ 18 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592915] uhci_hcd 0000:00:1d.3: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592930] usb usb7: root hub lost power or was reset Jun 1 10:42:21 igor-laptop kernel: [ 2225.592946] usb usb8: root hub lost power or was reset Jun 1 10:42:21 igor-laptop kernel: [ 2225.592949] ehci_hcd 0000:00:1d.7: PCI INT A -> GSI 20 (level, low) -> IRQ 20 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592957] ehci_hcd 0000:00:1d.7: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.592963] pci 0000:00:1e.0: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.597106] sd 0:0:0:0: [sda] Starting disk Jun 1 10:42:21 igor-laptop kernel: [ 2225.608138] snd_hda_intel 0000:00:1b.0: BAR 0: set to [mem 0xdf300000-0xdf303fff 64bit] (PCI address [0xdf300000-0xdf303fff]) Jun 1 10:42:21 igor-laptop kernel: [ 2225.608180] snd_hda_intel 0000:00:1b.0: restoring config space at offset 0xf (was 0x100, writing 0x10b) Jun 1 10:42:21 igor-laptop kernel: [ 2225.608233] snd_hda_intel 0000:00:1b.0: restoring config space at offset 0x3 (was 0x0, writing 0x10) Jun 1 10:42:21 igor-laptop kernel: [ 2225.608248] snd_hda_intel 0000:00:1b.0: restoring config space at offset 0x1 (was 0x100000, writing 0x100002) Jun 1 10:42:21 igor-laptop kernel: [ 2225.608299] snd_hda_intel 0000:00:1b.0: PCI INT A -> GSI 22 (level, low) -> IRQ 22 Jun 1 10:42:21 igor-laptop kernel: [ 2225.608313] snd_hda_intel 0000:00:1b.0: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.608420] snd_hda_intel 0000:00:1b.0: irq 50 for MSI/MSI-X Jun 1 10:42:21 igor-laptop kernel: [ 2225.612095] firewire_ohci 0000:06:00.0: restoring config space at offset 0x1 (was 0x100000, writing 0x100006) Jun 1 10:42:21 igor-laptop kernel: [ 2225.612181] sdhci-pci 0000:06:00.1: restoring config space at offset 0x1 (was 0x100003, writing 0x100007) Jun 1 10:42:21 igor-laptop kernel: [ 2225.612211] sdhci-pci 0000:06:00.1: PCI INT A -> GSI 16 (level, low) -> IRQ 16 Jun 1 10:42:21 igor-laptop kernel: [ 2225.612225] sdhci-pci 0000:06:00.1: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.612296] jmb38x_ms 0000:06:00.3: restoring config space at offset 0x1 (was 0x100003, writing 0x100007) Jun 1 10:42:21 igor-laptop kernel: [ 2225.612326] jmb38x_ms 0000:06:00.3: PCI INT A -> GSI 16 (level, low) -> IRQ 16 Jun 1 10:42:21 igor-laptop kernel: [ 2225.612332] jmb38x_ms 0000:06:00.3: setting latency timer to 64 Jun 1 10:42:21 igor-laptop kernel: [ 2225.699170] PM: resume of drv:uvcvideo dev:2-4:1.0 complete after 101.965 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.699179] PM: resume of drv:uvcvideo dev:2-4:1.1 complete after 101.932 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.699186] PM: resume of drv: dev:ep_00 complete after 101.917 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.699197] PM: resume of drv: dev:ep_83 complete after 101.972 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.716148] PM: resume of drv:hub dev:3-0:1.0 complete after 119.543 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.716155] PM: resume of drv: dev:ep_00 complete after 119.544 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.716161] PM: resume of drv:hub dev:5-0:1.0 complete after 119.420 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.716168] PM: resume of drv: dev:ep_00 complete after 119.381 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.716174] PM: resume of drv:hub dev:8-0:1.0 complete after 119.141 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.716181] PM: resume of drv: dev:ep_00 complete after 119.104 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.716186] PM: resume of drv: dev:ep_81 complete after 119.579 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.716191] PM: resume of drv: dev:ep_81 complete after 119.427 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.716197] PM: resume of drv: dev:ep_81 complete after 119.143 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.747148] firewire_core: skipped bus generations, destroying all nodes Jun 1 10:42:21 igor-laptop kernel: [ 2225.776093] PM: resume of drv:hp_accel dev:HPQ0004:00 complete after 167.225 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.777243] i8042 kbd 00:08: wake-up capability disabled by ACPI Jun 1 10:42:21 igor-laptop kernel: [ 2225.777278] ene_ir 00:0a: wake-up capability disabled by ACPI Jun 1 10:42:21 igor-laptop kernel: [ 2225.820100] PM: resume of drv:hub dev:4-0:1.0 complete after 223.436 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.820115] PM: resume of drv: dev:ep_00 complete after 223.444 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.820123] PM: resume of drv: dev:ep_81 complete after 223.456 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.820206] PM: resume of drv:hub dev:7-0:1.0 complete after 223.266 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.820221] PM: resume of drv: dev:ep_81 complete after 223.260 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.820238] PM: resume of drv: dev:ep_00 complete after 223.255 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.820295] PM: resume of drv:hub dev:6-0:1.0 complete after 223.453 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.820302] PM: resume of drv: dev:ep_00 complete after 223.415 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.820321] PM: resume of drv: dev:ep_81 complete after 223.457 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2225.932108] usb 4-2: reset full-speed USB device number 2 using uhci_hcd Jun 1 10:42:21 igor-laptop kernel: [ 2226.086714] PM: resume of drv:usbhid dev:4-2:1.0 complete after 489.393 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.086728] PM: resume of drv: dev:ep_81 complete after 489.384 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.086745] PM: resume of drv: dev:ep_00 complete after 489.329 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.086753] PM: resume of drv:usbhid dev:4-2:1.1 complete after 489.384 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.086764] PM: resume of drv: dev:ep_82 complete after 489.373 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.180555] usb 7-2: reset full-speed USB device number 2 using uhci_hcd Jun 1 10:42:21 igor-laptop kernel: [ 2226.244858] firewire_core: rediscovered device fw0 Jun 1 10:42:21 igor-laptop kernel: [ 2226.335066] btusb 7-2:1.0: no reset_resume for driver btusb? Jun 1 10:42:21 igor-laptop kernel: [ 2226.335068] btusb 7-2:1.1: no reset_resume for driver btusb? Jun 1 10:42:21 igor-laptop kernel: [ 2226.432082] usb 6-1: reset full-speed USB device number 2 using uhci_hcd Jun 1 10:42:21 igor-laptop kernel: [ 2226.578280] PM: resume of drv:nvidia dev:0000:01:00.0 complete after 985.301 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584296] PM: resume of drv:usb dev:7-2:1.0 complete after 986.693 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584308] PM: resume of drv: dev:ep_00 complete after 986.452 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584311] PM: resume of drv:usb dev:7-2:1.1 complete after 986.616 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584315] PM: resume of drv:usb dev:7-2:1.3 complete after 986.483 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584320] PM: resume of drv:usb dev:7-2:1.2 complete after 986.556 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584328] PM: resume of drv: dev:ep_03 complete after 986.588 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584331] PM: resume of drv: dev:ep_81 complete after 986.704 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584334] PM: resume of drv: dev:ep_83 complete after 986.617 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584337] PM: resume of drv: dev:ep_82 complete after 986.688 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584340] PM: resume of drv: dev:ep_02 complete after 986.667 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584344] PM: resume of drv: dev:ep_84 complete after 986.558 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.584352] PM: resume of drv: dev:ep_04 complete after 986.542 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.590883] PM: resume of drv: dev:ep_00 complete after 993.327 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.590887] PM: resume of drv:usb dev:6-1:1.0 complete after 993.424 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.590927] PM: resume of drv: dev:ep_82 complete after 993.395 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.590934] PM: resume of drv: dev:ep_81 complete after 993.426 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.590940] PM: resume of drv: dev:ep_01 complete after 993.456 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.592450] PM: resume of drv:sd dev:0:0:0:0 complete after 995.343 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.592461] PM: resume of drv:scsi_disk dev:0:0:0:0 complete after 802.688 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.592472] PM: resume of drv:scsi_device dev:0:0:0:0 complete after 995.324 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.600339] PM: resume of devices complete after 1008.129 msecs Jun 1 10:42:21 igor-laptop kernel: [ 2226.601293] PM: resume devices took 1.008 seconds Jun 1 10:42:21 igor-laptop kernel: [ 2226.601330] PM: Finishing wakeup. Jun 1 10:42:21 igor-laptop kernel: [ 2226.601332] Restarting tasks ... done. Jun 1 10:42:21 igor-laptop kernel: [ 2226.625660] video LNXVIDEO:01: Restoring backlight state Jun 1 10:42:22 igor-laptop kernel: [ 2227.478921] iwlwifi 0000:02:00.0: L1 Disabled; Enabling L0S Jun 1 10:42:22 igor-laptop kernel: [ 2227.481981] iwlwifi 0000:02:00.0: Radio type=0x1-0x2-0x0 Jun 1 10:42:22 igor-laptop kernel: [ 2227.527727] ADDRCONF(NETDEV_UP): wlan0: link is not ready Jun 1 10:42:22 igor-laptop kernel: [ 2227.532468] r8169 0000:03:00.0: eth0: link down Jun 1 10:42:22 igor-laptop kernel: [ 2227.533967] ADDRCONF(NETDEV_UP): eth0: link is not ready pm_suspend.log: Fri Jun 1 10:42:14 MSK 2012: Running hooks for suspend. Running hook /usr/lib/pm-utils/sleep.d/000kernel-change suspend suspend: /usr/lib/pm-utils/sleep.d/000kernel-change suspend suspend: success. Running hook /usr/lib/pm-utils/sleep.d/00logging suspend suspend: Linux igor-laptop 3.2.0-25-generic #40-Ubuntu SMP Wed May 23 20:33:05 UTC 2012 i686 i686 i386 GNU/Linux Module Size Used by pci_stub 12550 1 vboxpci 22882 0 vboxnetadp 13328 0 vboxnetflt 27211 0 vboxdrv 252189 3 vboxpci,vboxnetadp,vboxnetflt dm_crypt 22528 0 snd_hda_codec_hdmi 31775 1 snd_hda_codec_idt 60251 1 arc4 12473 2 hp_wmi 13652 0 sparse_keymap 13658 1 hp_wmi rfcomm 38139 12 snd_hda_intel 32765 5 snd_hda_codec 109562 3 snd_hda_codec_hdmi,snd_hda_codec_idt,snd_hda_intel snd_hwdep 13276 1 snd_hda_codec bnep 17830 2 btusb 17912 2 bluetooth 158438 23 rfcomm,bnep,btusb joydev 17393 0 parport_pc 32114 0 snd_pcm 80845 4 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec ppdev 12849 0 uvcvideo 67203 0 binfmt_misc 17292 1 videodev 86588 1 uvcvideo snd_seq_midi 13132 0 snd_rawmidi 25424 1 snd_seq_midi nvidia 10958194 43 snd_seq_midi_event 14475 1 snd_seq_midi snd_seq 51567 2 snd_seq_midi,snd_seq_midi_event ir_lirc_codec 12739 0 lirc_dev 18700 1 ir_lirc_codec snd_timer 28931 2 snd_pcm,snd_seq snd_seq_device 14172 3 snd_seq_midi,snd_rawmidi,snd_seq ir_mce_kbd_decoder 12681 0 ir_sony_decoder 12462 0 ir_jvc_decoder 12459 0 ir_rc6_decoder 12459 0 psmouse 87213 0 ir_rc5_decoder 12459 0 serio_raw 13027 0 iwlwifi 287934 0 rc_rc6_mce 12454 0 ir_nec_decoder 12459 0 ene_ir 18019 0 rc_core 21263 10 ir_lirc_codec,ir_mce_kbd_decoder,ir_sony_decoder,ir_jvc_decoder,ir_rc6_decoder,ir_rc5_decoder,rc_rc6_mce,ir_nec_decoder,ene_ir mac80211 436455 1 iwlwifi snd 62064 19 snd_hda_codec_hdmi,snd_hda_codec_idt,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device cfg80211 178679 2 iwlwifi,mac80211 hp_accel 25728 0 lis3lv02d 19268 1 hp_accel input_polldev 13648 1 lis3lv02d mac_hid 13077 0 wmi 18744 1 hp_wmi jmb38x_ms 17406 0 soundcore 14635 1 snd snd_page_alloc 14115 2 snd_hda_intel,snd_pcm memstick 15857 1 jmb38x_ms firewire_sbp2 18346 0 lp 17455 0 parport 40930 3 parport_pc,ppdev,lp vesafb 13516 1 usbhid 41906 0 hid 77367 1 usbhid firewire_ohci 40180 0 firewire_core 56906 2 firewire_sbp2,firewire_ohci crc_itu_t 12627 1 firewire_core sdhci_pci 18324 0 sdhci 28241 1 sdhci_pci r8169 56321 0 video 19068 0 total used free shared buffers cached Mem: 3095544 2364260 731284 0 159020 1280240 -/+ buffers/cache: 925000 2170544 Swap: 1718916 0 1718916 /usr/lib/pm-utils/sleep.d/00logging suspend suspend: success. Running hook /usr/lib/pm-utils/sleep.d/00powersave suspend suspend: /usr/lib/pm-utils/sleep.d/00powersave suspend suspend: success. Running hook /usr/lib/pm-utils/sleep.d/01PulseAudio suspend suspend: Welcome to PulseAudio! Use "help" for usage information. >>> >>> Welcome to PulseAudio! Use "help" for usage information. >>> >>> Welcome to PulseAudio! Use "help" for usage information. >>> >>> /usr/lib/pm-utils/sleep.d/01PulseAudio suspend suspend: success. Running hook /etc/pm/sleep.d/10_grub-common suspend suspend: /etc/pm/sleep.d/10_grub-common suspend suspend: success. Running hook /etc/pm/sleep.d/10_unattended-upgrades-hibernate suspend suspend: /etc/pm/sleep.d/10_unattended-upgrades-hibernate suspend suspend: success. Running hook /usr/lib/pm-utils/sleep.d/55NetworkManager suspend suspend: Having NetworkManager put all interaces to sleep...Failed. /usr/lib/pm-utils/sleep.d/55NetworkManager suspend suspend: success. Running hook /usr/lib/pm-utils/sleep.d/60_wpa_supplicant suspend suspend: Failed to connect to wpa_supplicant - wpa_ctrl_open: No such file or directory /usr/lib/pm-utils/sleep.d/60_wpa_supplicant suspend suspend: success. Running hook /usr/lib/pm-utils/sleep.d/75modules suspend suspend: /usr/lib/pm-utils/sleep.d/75modules suspend suspend: success. Running hook /usr/lib/pm-utils/sleep.d/90clock suspend suspend: /usr/lib/pm-utils/sleep.d/90clock suspend suspend: not applicable. Running hook /usr/lib/pm-utils/sleep.d/94cpufreq suspend suspend: /usr/lib/pm-utils/sleep.d/94cpufreq suspend suspend: success. Running hook /usr/lib/pm-utils/sleep.d/95anacron suspend suspend: stop: Unknown instance: /usr/lib/pm-utils/sleep.d/95anacron suspend suspend: success. Running hook /usr/lib/pm-utils/sleep.d/95hdparm-apm suspend suspend: /usr/lib/pm-utils/sleep.d/95hdparm-apm suspend suspend: not applicable. Running hook /usr/lib/pm-utils/sleep.d/95led suspend suspend: /usr/lib/pm-utils/sleep.d/95led suspend suspend: not applicable. Running hook /usr/lib/pm-utils/sleep.d/98video-quirk-db-handler suspend suspend: nVidia binary video drive detected, not using quirks. /usr/lib/pm-utils/sleep.d/98video-quirk-db-handler suspend suspend: success. Running hook /usr/lib/pm-utils/sleep.d/99video suspend suspend: kernel.acpi_video_flags = 0 /usr/lib/pm-utils/sleep.d/99video suspend suspend: success. Running hook /etc/pm/sleep.d/novatel_3g_suspend suspend suspend: /etc/pm/sleep.d/novatel_3g_suspend suspend suspend: success. Fri Jun 1 10:42:19 MSK 2012: performing suspend Fri Jun 1 10:42:21 MSK 2012: Awake. Fri Jun 1 10:42:21 MSK 2012: Running hooks for resume Running hook /etc/pm/sleep.d/novatel_3g_suspend resume suspend: /etc/pm/sleep.d/novatel_3g_suspend resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/99video resume suspend: /usr/lib/pm-utils/sleep.d/99video resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/98video-quirk-db-handler resume suspend: /usr/lib/pm-utils/sleep.d/98video-quirk-db-handler resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/95led resume suspend: /usr/lib/pm-utils/sleep.d/95led resume suspend: not applicable. Running hook /usr/lib/pm-utils/sleep.d/95hdparm-apm resume suspend: /dev/sda: setting Advanced Power Management level to 0xfe (254) APM_level = 254 /dev/sda: setting Advanced Power Management level to 0xfe (254) APM_level = 254 /usr/lib/pm-utils/sleep.d/95hdparm-apm resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/95anacron resume suspend: /usr/lib/pm-utils/sleep.d/95anacron resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/94cpufreq resume suspend: /usr/lib/pm-utils/sleep.d/94cpufreq resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/90clock resume suspend: /usr/lib/pm-utils/sleep.d/90clock resume suspend: not applicable. Running hook /usr/lib/pm-utils/sleep.d/75modules resume suspend: Reloaded unloaded modules. /usr/lib/pm-utils/sleep.d/75modules resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/60_wpa_supplicant resume suspend: Failed to connect to wpa_supplicant - wpa_ctrl_open: No such file or directory /usr/lib/pm-utils/sleep.d/60_wpa_supplicant resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/55NetworkManager resume suspend: Having NetworkManager wake interfaces back up...Failed. /usr/lib/pm-utils/sleep.d/55NetworkManager resume suspend: success. Running hook /etc/pm/sleep.d/10_unattended-upgrades-hibernate resume suspend: /etc/pm/sleep.d/10_unattended-upgrades-hibernate resume suspend: success. Running hook /etc/pm/sleep.d/10_grub-common resume suspend: /etc/pm/sleep.d/10_grub-common resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/01PulseAudio resume suspend: Welcome to PulseAudio! Use "help" for usage information. >>> >>> Welcome to PulseAudio! Use "help" for usage information. >>> >>> Welcome to PulseAudio! Use "help" for usage information. >>> >>> /usr/lib/pm-utils/sleep.d/01PulseAudio resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/00powersave resume suspend: /usr/lib/pm-utils/sleep.d/00powersave resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/00logging resume suspend: /usr/lib/pm-utils/sleep.d/00logging resume suspend: success. Running hook /usr/lib/pm-utils/sleep.d/000kernel-change resume suspend: /usr/lib/pm-utils/sleep.d/000kernel-change resume suspend: success. Fri Jun 1 10:42:22 MSK 2012: Finished.

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• Advanced TSQL Tuning: Why Internals Knowledge Matters

  - by Paul White

  There is much more to query tuning than reducing logical reads and adding covering nonclustered indexes.  Query tuning is not complete as soon as the query returns results quickly in the development or test environments.  In production, your query will compete for memory, CPU, locks, I/O and other resources on the server.  Today’s entry looks at some tuning considerations that are often overlooked, and shows how deep internals knowledge can help you write better TSQL. As always, we’ll need some example data.  In fact, we are going to use three tables today, each of which is structured like this: Each table has 50,000 rows made up of an INTEGER id column and a padding column containing 3,999 characters in every row.  The only difference between the three tables is in the type of the padding column: the first table uses CHAR(3999), the second uses VARCHAR(MAX), and the third uses the deprecated TEXT type.  A script to create a database with the three tables and load the sample data follows: USE master; GO IF DB_ID('SortTest') IS NOT NULL DROP DATABASE SortTest; GO CREATE DATABASE SortTest COLLATE LATIN1_GENERAL_BIN; GO ALTER DATABASE SortTest MODIFY FILE ( NAME = 'SortTest', SIZE = 3GB, MAXSIZE = 3GB ); GO ALTER DATABASE SortTest MODIFY FILE ( NAME = 'SortTest_log', SIZE = 256MB, MAXSIZE = 1GB, FILEGROWTH = 128MB ); GO ALTER DATABASE SortTest SET ALLOW_SNAPSHOT_ISOLATION OFF ; ALTER DATABASE SortTest SET AUTO_CLOSE OFF ; ALTER DATABASE SortTest SET AUTO_CREATE_STATISTICS ON ; ALTER DATABASE SortTest SET AUTO_SHRINK OFF ; ALTER DATABASE SortTest SET AUTO_UPDATE_STATISTICS ON ; ALTER DATABASE SortTest SET AUTO_UPDATE_STATISTICS_ASYNC ON ; ALTER DATABASE SortTest SET PARAMETERIZATION SIMPLE ; ALTER DATABASE SortTest SET READ_COMMITTED_SNAPSHOT OFF ; ALTER DATABASE SortTest SET MULTI_USER ; ALTER DATABASE SortTest SET RECOVERY SIMPLE ; USE SortTest; GO CREATE TABLE dbo.TestCHAR ( id INTEGER IDENTITY (1,1) NOT NULL, padding CHAR(3999) NOT NULL,   CONSTRAINT [PK dbo.TestCHAR (id)] PRIMARY KEY CLUSTERED (id), ) ; CREATE TABLE dbo.TestMAX ( id INTEGER IDENTITY (1,1) NOT NULL, padding VARCHAR(MAX) NOT NULL,   CONSTRAINT [PK dbo.TestMAX (id)] PRIMARY KEY CLUSTERED (id), ) ; CREATE TABLE dbo.TestTEXT ( id INTEGER IDENTITY (1,1) NOT NULL, padding TEXT NOT NULL,   CONSTRAINT [PK dbo.TestTEXT (id)] PRIMARY KEY CLUSTERED (id), ) ; -- ============= -- Load TestCHAR (about 3s) -- ============= INSERT INTO dbo.TestCHAR WITH (TABLOCKX) ( padding ) SELECT padding = REPLICATE(CHAR(65 + (Data.n % 26)), 3999) FROM ( SELECT TOP (50000) n = ROW_NUMBER() OVER (ORDER BY (SELECT 0)) - 1 FROM master.sys.columns C1, master.sys.columns C2, master.sys.columns C3 ORDER BY n ASC ) AS Data ORDER BY Data.n ASC ; -- ============ -- Load TestMAX (about 3s) -- ============ INSERT INTO dbo.TestMAX WITH (TABLOCKX) ( padding ) SELECT CONVERT(VARCHAR(MAX), padding) FROM dbo.TestCHAR ORDER BY id ; -- ============= -- Load TestTEXT (about 5s) -- ============= INSERT INTO dbo.TestTEXT WITH (TABLOCKX) ( padding ) SELECT CONVERT(TEXT, padding) FROM dbo.TestCHAR ORDER BY id ; -- ========== -- Space used -- ========== -- EXECUTE sys.sp_spaceused @objname = 'dbo.TestCHAR'; EXECUTE sys.sp_spaceused @objname = 'dbo.TestMAX'; EXECUTE sys.sp_spaceused @objname = 'dbo.TestTEXT'; ; CHECKPOINT ; That takes around 15 seconds to run, and shows the space allocated to each table in its output: To illustrate the points I want to make today, the example task we are going to set ourselves is to return a random set of 150 rows from each table.  The basic shape of the test query is the same for each of the three test tables: SELECT TOP (150) T.id, T.padding FROM dbo.Test AS T ORDER BY NEWID() OPTION (MAXDOP 1) ; Test 1 – CHAR(3999) Running the template query shown above using the TestCHAR table as the target, we find that the query takes around 5 seconds to return its results.  This seems slow, considering that the table only has 50,000 rows.  Working on the assumption that generating a GUID for each row is a CPU-intensive operation, we might try enabling parallelism to see if that speeds up the response time.  Running the query again (but without the MAXDOP 1 hint) on a machine with eight logical processors, the query now takes 10 seconds to execute – twice as long as when run serially. Rather than attempting further guesses at the cause of the slowness, let’s go back to serial execution and add some monitoring.  The script below monitors STATISTICS IO output and the amount of tempdb used by the test query.  We will also run a Profiler trace to capture any warnings generated during query execution. DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) TC.id, TC.padding FROM dbo.TestCHAR AS TC ORDER BY NEWID() OPTION (MAXDOP 1) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; Let’s take a closer look at the statistics and query plan generated from this: Following the flow of the data from right to left, we see the expected 50,000 rows emerging from the Clustered Index Scan, with a total estimated size of around 191MB.  The Compute Scalar adds a column containing a random GUID (generated from the NEWID() function call) for each row.  With this extra column in place, the size of the data arriving at the Sort operator is estimated to be 192MB. Sort is a blocking operator – it has to examine all of the rows on its input before it can produce its first row of output (the last row received might sort first).  This characteristic means that Sort requires a memory grant – memory allocated for the query’s use by SQL Server just before execution starts.  In this case, the Sort is the only memory-consuming operator in the plan, so it has access to the full 243MB (248,696KB) of memory reserved by SQL Server for this query execution. Notice that the memory grant is significantly larger than the expected size of the data to be sorted.  SQL Server uses a number of techniques to speed up sorting, some of which sacrifice size for comparison speed.  Sorts typically require a very large number of comparisons, so this is usually a very effective optimization.  One of the drawbacks is that it is not possible to exactly predict the sort space needed, as it depends on the data itself.  SQL Server takes an educated guess based on data types, sizes, and the number of rows expected, but the algorithm is not perfect. In spite of the large memory grant, the Profiler trace shows a Sort Warning event (indicating that the sort ran out of memory), and the tempdb usage monitor shows that 195MB of tempdb space was used – all of that for system use.  The 195MB represents physical write activity on tempdb, because SQL Server strictly enforces memory grants – a query cannot ‘cheat’ and effectively gain extra memory by spilling to tempdb pages that reside in memory.  Anyway, the key point here is that it takes a while to write 195MB to disk, and this is the main reason that the query takes 5 seconds overall. If you are wondering why using parallelism made the problem worse, consider that eight threads of execution result in eight concurrent partial sorts, each receiving one eighth of the memory grant.  The eight sorts all spilled to tempdb, resulting in inefficiencies as the spilled sorts competed for disk resources.  More importantly, there are specific problems at the point where the eight partial results are combined, but I’ll cover that in a future post. CHAR(3999) Performance Summary: 5 seconds elapsed time 243MB memory grant 195MB tempdb usage 192MB estimated sort set 25,043 logical reads Sort Warning Test 2 – VARCHAR(MAX) We’ll now run exactly the same test (with the additional monitoring) on the table using a VARCHAR(MAX) padding column: DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) TM.id, TM.padding FROM dbo.TestMAX AS TM ORDER BY NEWID() OPTION (MAXDOP 1) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; This time the query takes around 8 seconds to complete (3 seconds longer than Test 1).  Notice that the estimated row and data sizes are very slightly larger, and the overall memory grant has also increased very slightly to 245MB.  The most marked difference is in the amount of tempdb space used – this query wrote almost 391MB of sort run data to the physical tempdb file.  Don’t draw any general conclusions about VARCHAR(MAX) versus CHAR from this – I chose the length of the data specifically to expose this edge case.  In most cases, VARCHAR(MAX) performs very similarly to CHAR – I just wanted to make test 2 a bit more exciting. MAX Performance Summary: 8 seconds elapsed time 245MB memory grant 391MB tempdb usage 193MB estimated sort set 25,043 logical reads Sort warning Test 3 – TEXT The same test again, but using the deprecated TEXT data type for the padding column: DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) TT.id, TT.padding FROM dbo.TestTEXT AS TT ORDER BY NEWID() OPTION (MAXDOP 1, RECOMPILE) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; This time the query runs in 500ms.  If you look at the metrics we have been checking so far, it’s not hard to understand why: TEXT Performance Summary: 0.5 seconds elapsed time 9MB memory grant 5MB tempdb usage 5MB estimated sort set 207 logical reads 596 LOB logical reads Sort warning SQL Server’s memory grant algorithm still underestimates the memory needed to perform the sorting operation, but the size of the data to sort is so much smaller (5MB versus 193MB previously) that the spilled sort doesn’t matter very much.  Why is the data size so much smaller?  The query still produces the correct results – including the large amount of data held in the padding column – so what magic is being performed here? TEXT versus MAX Storage The answer lies in how columns of the TEXT data type are stored.  By default, TEXT data is stored off-row in separate LOB pages – which explains why this is the first query we have seen that records LOB logical reads in its STATISTICS IO output.  You may recall from my last post that LOB data leaves an in-row pointer to the separate storage structure holding the LOB data. SQL Server can see that the full LOB value is not required by the query plan until results are returned, so instead of passing the full LOB value down the plan from the Clustered Index Scan, it passes the small in-row structure instead.  SQL Server estimates that each row coming from the scan will be 79 bytes long – 11 bytes for row overhead, 4 bytes for the integer id column, and 64 bytes for the LOB pointer (in fact the pointer is rather smaller – usually 16 bytes – but the details of that don’t really matter right now). OK, so this query is much more efficient because it is sorting a very much smaller data set – SQL Server delays retrieving the LOB data itself until after the Sort starts producing its 150 rows.  The question that normally arises at this point is: Why doesn’t SQL Server use the same trick when the padding column is defined as VARCHAR(MAX)? The answer is connected with the fact that if the actual size of the VARCHAR(MAX) data is 8000 bytes or less, it is usually stored in-row in exactly the same way as for a VARCHAR(8000) column – MAX data only moves off-row into LOB storage when it exceeds 8000 bytes.  The default behaviour of the TEXT type is to be stored off-row by default, unless the ‘text in row’ table option is set suitably and there is room on the page.  There is an analogous (but opposite) setting to control the storage of MAX data – the ‘large value types out of row’ table option.  By enabling this option for a table, MAX data will be stored off-row (in a LOB structure) instead of in-row.  SQL Server Books Online has good coverage of both options in the topic In Row Data. The MAXOOR Table The essential difference, then, is that MAX defaults to in-row storage, and TEXT defaults to off-row (LOB) storage.  You might be thinking that we could get the same benefits seen for the TEXT data type by storing the VARCHAR(MAX) values off row – so let’s look at that option now.  This script creates a fourth table, with the VARCHAR(MAX) data stored off-row in LOB pages: CREATE TABLE dbo.TestMAXOOR ( id INTEGER IDENTITY (1,1) NOT NULL, padding VARCHAR(MAX) NOT NULL,   CONSTRAINT [PK dbo.TestMAXOOR (id)] PRIMARY KEY CLUSTERED (id), ) ; EXECUTE sys.sp_tableoption @TableNamePattern = N'dbo.TestMAXOOR', @OptionName = 'large value types out of row', @OptionValue = 'true' ; SELECT large_value_types_out_of_row FROM sys.tables WHERE [schema_id] = SCHEMA_ID(N'dbo') AND name = N'TestMAXOOR' ; INSERT INTO dbo.TestMAXOOR WITH (TABLOCKX) ( padding ) SELECT SPACE(0) FROM dbo.TestCHAR ORDER BY id ; UPDATE TM WITH (TABLOCK) SET padding.WRITE (TC.padding, NULL, NULL) FROM dbo.TestMAXOOR AS TM JOIN dbo.TestCHAR AS TC ON TC.id = TM.id ; EXECUTE sys.sp_spaceused @objname = 'dbo.TestMAXOOR' ; CHECKPOINT ; Test 4 – MAXOOR We can now re-run our test on the MAXOOR (MAX out of row) table: DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) MO.id, MO.padding FROM dbo.TestMAXOOR AS MO ORDER BY NEWID() OPTION (MAXDOP 1, RECOMPILE) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; TEXT Performance Summary: 0.3 seconds elapsed time 245MB memory grant 0MB tempdb usage 193MB estimated sort set 207 logical reads 446 LOB logical reads No sort warning The query runs very quickly – slightly faster than Test 3, and without spilling the sort to tempdb (there is no sort warning in the trace, and the monitoring query shows zero tempdb usage by this query).  SQL Server is passing the in-row pointer structure down the plan and only looking up the LOB value on the output side of the sort. The Hidden Problem There is still a huge problem with this query though – it requires a 245MB memory grant.  No wonder the sort doesn’t spill to tempdb now – 245MB is about 20 times more memory than this query actually requires to sort 50,000 records containing LOB data pointers.  Notice that the estimated row and data sizes in the plan are the same as in test 2 (where the MAX data was stored in-row). The optimizer assumes that MAX data is stored in-row, regardless of the sp_tableoption setting ‘large value types out of row’.  Why?  Because this option is dynamic – changing it does not immediately force all MAX data in the table in-row or off-row, only when data is added or actually changed.  SQL Server does not keep statistics to show how much MAX or TEXT data is currently in-row, and how much is stored in LOB pages.  This is an annoying limitation, and one which I hope will be addressed in a future version of the product. So why should we worry about this?  Excessive memory grants reduce concurrency and may result in queries waiting on the RESOURCE_SEMAPHORE wait type while they wait for memory they do not need.  245MB is an awful lot of memory, especially on 32-bit versions where memory grants cannot use AWE-mapped memory.  Even on a 64-bit server with plenty of memory, do you really want a single query to consume 0.25GB of memory unnecessarily?  That’s 32,000 8KB pages that might be put to much better use. The Solution The answer is not to use the TEXT data type for the padding column.  That solution happens to have better performance characteristics for this specific query, but it still results in a spilled sort, and it is hard to recommend the use of a data type which is scheduled for removal.  I hope it is clear to you that the fundamental problem here is that SQL Server sorts the whole set arriving at a Sort operator.  Clearly, it is not efficient to sort the whole table in memory just to return 150 rows in a random order. The TEXT example was more efficient because it dramatically reduced the size of the set that needed to be sorted.  We can do the same thing by selecting 150 unique keys from the table at random (sorting by NEWID() for example) and only then retrieving the large padding column values for just the 150 rows we need.  The following script implements that idea for all four tables: SET STATISTICS IO ON ; WITH TestTable AS ( SELECT * FROM dbo.TestCHAR ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id = ANY (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; WITH TestTable AS ( SELECT * FROM dbo.TestMAX ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id IN (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; WITH TestTable AS ( SELECT * FROM dbo.TestTEXT ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id IN (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; WITH TestTable AS ( SELECT * FROM dbo.TestMAXOOR ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id IN (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; SET STATISTICS IO OFF ; All four queries now return results in much less than a second, with memory grants between 6 and 12MB, and without spilling to tempdb.  The small remaining inefficiency is in reading the id column values from the clustered primary key index.  As a clustered index, it contains all the in-row data at its leaf.  The CHAR and VARCHAR(MAX) tables store the padding column in-row, so id values are separated by a 3999-character column, plus row overhead.  The TEXT and MAXOOR tables store the padding values off-row, so id values in the clustered index leaf are separated by the much-smaller off-row pointer structure.  This difference is reflected in the number of logical page reads performed by the four queries: Table 'TestCHAR' logical reads 25511 lob logical reads 000 Table 'TestMAX'. logical reads 25511 lob logical reads 000 Table 'TestTEXT' logical reads 00412 lob logical reads 597 Table 'TestMAXOOR' logical reads 00413 lob logical reads 446 We can increase the density of the id values by creating a separate nonclustered index on the id column only.  This is the same key as the clustered index, of course, but the nonclustered index will not include the rest of the in-row column data. CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestCHAR (id); CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestMAX (id); CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestTEXT (id); CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestMAXOOR (id); The four queries can now use the very dense nonclustered index to quickly scan the id values, sort them by NEWID(), select the 150 ids we want, and then look up the padding data.  The logical reads with the new indexes in place are: Table 'TestCHAR' logical reads 835 lob logical reads 0 Table 'TestMAX' logical reads 835 lob logical reads 0 Table 'TestTEXT' logical reads 686 lob logical reads 597 Table 'TestMAXOOR' logical reads 686 lob logical reads 448 With the new index, all four queries use the same query plan (click to enlarge): Performance Summary: 0.3 seconds elapsed time 6MB memory grant 0MB tempdb usage 1MB sort set 835 logical reads (CHAR, MAX) 686 logical reads (TEXT, MAXOOR) 597 LOB logical reads (TEXT) 448 LOB logical reads (MAXOOR) No sort warning I’ll leave it as an exercise for the reader to work out why trying to eliminate the Key Lookup by adding the padding column to the new nonclustered indexes would be a daft idea Conclusion This post is not about tuning queries that access columns containing big strings.  It isn’t about the internal differences between TEXT and MAX data types either.  It isn’t even about the cool use of UPDATE .WRITE used in the MAXOOR table load.  No, this post is about something else: Many developers might not have tuned our starting example query at all – 5 seconds isn’t that bad, and the original query plan looks reasonable at first glance.  Perhaps the NEWID() function would have been blamed for ‘just being slow’ – who knows.  5 seconds isn’t awful – unless your users expect sub-second responses – but using 250MB of memory and writing 200MB to tempdb certainly is!  If ten sessions ran that query at the same time in production that’s 2.5GB of memory usage and 2GB hitting tempdb.  Of course, not all queries can be rewritten to avoid large memory grants and sort spills using the key-lookup technique in this post, but that’s not the point either. The point of this post is that a basic understanding of execution plans is not enough.  Tuning for logical reads and adding covering indexes is not enough.  If you want to produce high-quality, scalable TSQL that won’t get you paged as soon as it hits production, you need a deep understanding of execution plans, and as much accurate, deep knowledge about SQL Server as you can lay your hands on.  The advanced database developer has a wide range of tools to use in writing queries that perform well in a range of circumstances. By the way, the examples in this post were written for SQL Server 2008.  They will run on 2005 and demonstrate the same principles, but you won’t get the same figures I did because 2005 had a rather nasty bug in the Top N Sort operator.  Fair warning: if you do decide to run the scripts on a 2005 instance (particularly the parallel query) do it before you head out for lunch… This post is dedicated to the people of Christchurch, New Zealand. © 2011 Paul White email: @[email protected] twitter: @SQL_Kiwi

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• C#/.NET Little Wonders: The ConcurrentDictionary

  - by James Michael Hare

  Once again we consider some of the lesser known classes and keywords of C#.  In this series of posts, we will discuss how the concurrent collections have been developed to help alleviate these multi-threading concerns.  Last week’s post began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  Today's post discusses the ConcurrentDictionary<T> (originally I had intended to discuss ConcurrentBag this week as well, but ConcurrentDictionary had enough information to create a very full post on its own!).  Finally next week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. Recap As you'll recall from the previous post, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  While these were convenient because you didn't have to worry about writing your own synchronization logic, they were a bit too finely grained and if you needed to perform multiple operations under one lock, the automatic synchronization didn't buy much. With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  This cuts both ways in that you have a lot more control as a developer over when and how fine-grained you want to synchronize, but on the other hand if you just want simple synchronization it creates more work. With .NET 4.0, we get the best of both worlds in generic collections.  A new breed of collections was born called the concurrent collections in the System.Collections.Concurrent namespace.  These amazing collections are fine-tuned to have best overall performance for situations requiring concurrent access.  They are not meant to replace the generic collections, but to simply be an alternative to creating your own locking mechanisms. Among those concurrent collections were the ConcurrentStack<T> and ConcurrentQueue<T> which provide classic LIFO and FIFO collections with a concurrent twist.  As we saw, some of the traditional methods that required calls to be made in a certain order (like checking for not IsEmpty before calling Pop()) were replaced in favor of an umbrella operation that combined both under one lock (like TryPop()). Now, let's take a look at the next in our series of concurrent collections!For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentDictionary – the fully thread-safe dictionary The ConcurrentDictionary<TKey,TValue> is the thread-safe counterpart to the generic Dictionary<TKey, TValue> collection.  Obviously, both are designed for quick – O(1) – lookups of data based on a key.  If you think of algorithms where you need lightning fast lookups of data and don’t care whether the data is maintained in any particular ordering or not, the unsorted dictionaries are generally the best way to go. Note: as a side note, there are sorted implementations of IDictionary, namely SortedDictionary and SortedList which are stored as an ordered tree and a ordered list respectively.  While these are not as fast as the non-sorted dictionaries – they are O(log2 n) – they are a great combination of both speed and ordering -- and still greatly outperform a linear search. Now, once again keep in mind that if all you need to do is load a collection once and then allow multi-threaded reading you do not need any locking.  Examples of this tend to be situations where you load a lookup or translation table once at program start, then keep it in memory for read-only reference.  In such cases locking is completely non-productive. However, most of the time when we need a concurrent dictionary we are interleaving both reads and updates.  This is where the ConcurrentDictionary really shines!  It achieves its thread-safety with no common lock to improve efficiency.  It actually uses a series of locks to provide concurrent updates, and has lockless reads!  This means that the ConcurrentDictionary gets even more efficient the higher the ratio of reads-to-writes you have. ConcurrentDictionary and Dictionary differences For the most part, the ConcurrentDictionary<TKey,TValue> behaves like it’s Dictionary<TKey,TValue> counterpart with a few differences.  Some notable examples of which are: Add() does not exist in the concurrent dictionary. This means you must use TryAdd(), AddOrUpdate(), or GetOrAdd().  It also means that you can’t use a collection initializer with the concurrent dictionary. TryAdd() replaced Add() to attempt atomic, safe adds. Because Add() only succeeds if the item doesn’t already exist, we need an atomic operation to check if the item exists, and if not add it while still under an atomic lock. TryUpdate() was added to attempt atomic, safe updates. If we want to update an item, we must make sure it exists first and that the original value is what we expected it to be.  If all these are true, we can update the item under one atomic step. TryRemove() was added to attempt atomic, safe removes. To safely attempt to remove a value we need to see if the key exists first, this checks for existence and removes under an atomic lock. AddOrUpdate() was added to attempt an thread-safe “upsert”. There are many times where you want to insert into a dictionary if the key doesn’t exist, or update the value if it does.  This allows you to make a thread-safe add-or-update. GetOrAdd() was added to attempt an thread-safe query/insert. Sometimes, you want to query for whether an item exists in the cache, and if it doesn’t insert a starting value for it.  This allows you to get the value if it exists and insert if not. Count, Keys, Values properties take a snapshot of the dictionary. Accessing these properties may interfere with add and update performance and should be used with caution. ToArray() returns a static snapshot of the dictionary. That is, the dictionary is locked, and then copied to an array as a O(n) operation.  GetEnumerator() is thread-safe and efficient, but allows dirty reads. Because reads require no locking, you can safely iterate over the contents of the dictionary.  The only downside is that, depending on timing, you may get dirty reads. Dirty reads during iteration The last point on GetEnumerator() bears some explanation.  Picture a scenario in which you call GetEnumerator() (or iterate using a foreach, etc.) and then, during that iteration the dictionary gets updated.  This may not sound like a big deal, but it can lead to inconsistent results if used incorrectly.  The problem is that items you already iterated over that are updated a split second after don’t show the update, but items that you iterate over that were updated a split second before do show the update.  Thus you may get a combination of items that are “stale” because you iterated before the update, and “fresh” because they were updated after GetEnumerator() but before the iteration reached them. Let’s illustrate with an example, let’s say you load up a concurrent dictionary like this: 1: // load up a dictionary. 2: var dictionary = new ConcurrentDictionary<string, int>(); 3:  4: dictionary["A"] = 1; 5: dictionary["B"] = 2; 6: dictionary["C"] = 3; 7: dictionary["D"] = 4; 8: dictionary["E"] = 5; 9: dictionary["F"] = 6; Then you have one task (using the wonderful TPL!) to iterate using dirty reads: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); And one task to attempt updates in a separate thread (probably): 1: // attempt updates in a separate thread 2: var updateTask = new Task(() => 3: { 4: // iterates, and updates the value by one 5: foreach (var pair in dictionary) 6: { 7: dictionary[pair.Key] = pair.Value + 1; 8: } 9: }); Now that we’ve done this, we can fire up both tasks and wait for them to complete: 1: // start both tasks 2: updateTask.Start(); 3: iterationTask.Start(); 4:  5: // wait for both to complete. 6: Task.WaitAll(updateTask, iterationTask); Now, if I you didn’t know about the dirty reads, you may have expected to see the iteration before the updates (such as A:1, B:2, C:3, D:4, E:5, F:6).  However, because the reads are dirty, we will quite possibly get a combination of some updated, some original.  My own run netted this result: 1: F:6 2: E:6 3: D:5 4: C:4 5: B:3 6: A:2 Note that, of course, iteration is not in order because ConcurrentDictionary, like Dictionary, is unordered.  Also note that both E and F show the value 6.  This is because the output task reached F before the update, but the updates for the rest of the items occurred before their output (probably because console output is very slow, comparatively). If we want to always guarantee that we will get a consistent snapshot to iterate over (that is, at the point we ask for it we see precisely what is in the dictionary and no subsequent updates during iteration), we should iterate over a call to ToArray() instead: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary.ToArray()) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); The atomic Try…() methods As you can imagine TryAdd() and TryRemove() have few surprises.  Both first check the existence of the item to determine if it can be added or removed based on whether or not the key currently exists in the dictionary: 1: // try add attempts an add and returns false if it already exists 2: if (dictionary.TryAdd("G", 7)) 3: Console.WriteLine("G did not exist, now inserted with 7"); 4: else 5: Console.WriteLine("G already existed, insert failed."); TryRemove() also has the virtue of returning the value portion of the removed entry matching the given key: 1: // attempt to remove the value, if it exists it is removed and the original is returned 2: int removedValue; 3: if (dictionary.TryRemove("C", out removedValue)) 4: Console.WriteLine("Removed C and its value was " + removedValue); 5: else 6: Console.WriteLine("C did not exist, remove failed."); Now TryUpdate() is an interesting creature.  You might think from it’s name that TryUpdate() first checks for an item’s existence, and then updates if the item exists, otherwise it returns false.  Well, note quite... It turns out when you call TryUpdate() on a concurrent dictionary, you pass it not only the new value you want it to have, but also the value you expected it to have before the update.  If the item exists in the dictionary, and it has the value you expected, it will update it to the new value atomically and return true.  If the item is not in the dictionary or does not have the value you expected, it is not modified and false is returned. 1: // attempt to update the value, if it exists and if it has the expected original value 2: if (dictionary.TryUpdate("G", 42, 7)) 3: Console.WriteLine("G existed and was 7, now it's 42."); 4: else 5: Console.WriteLine("G either didn't exist, or wasn't 7."); The composite Add methods The ConcurrentDictionary also has composite add methods that can be used to perform updates and gets, with an add if the item is not existing at the time of the update or get. The first of these, AddOrUpdate(), allows you to add a new item to the dictionary if it doesn’t exist, or update the existing item if it does.  For example, let’s say you are creating a dictionary of counts of stock ticker symbols you’ve subscribed to from a market data feed: 1: public sealed class SubscriptionManager 2: { 3: private readonly ConcurrentDictionary<string, int> _subscriptions = new ConcurrentDictionary<string, int>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public void AddSubscription(string tickerKey) 7: { 8: // add a new subscription with count of 1, or update existing count by 1 if exists 9: var resultCount = _subscriptions.AddOrUpdate(tickerKey, 1, (symbol, count) => count + 1); 10:  11: // now check the result to see if we just incremented the count, or inserted first count 12: if (resultCount == 1) 13: { 14: // subscribe to symbol... 15: } 16: } 17: } Notice the update value factory Func delegate.  If the key does not exist in the dictionary, the add value is used (in this case 1 representing the first subscription for this symbol), but if the key already exists, it passes the key and current value to the update delegate which computes the new value to be stored in the dictionary.  The return result of this operation is the value used (in our case: 1 if added, existing value + 1 if updated). Likewise, the GetOrAdd() allows you to attempt to retrieve a value from the dictionary, and if the value does not currently exist in the dictionary it will insert a value.  This can be handy in cases where perhaps you wish to cache data, and thus you would query the cache to see if the item exists, and if it doesn’t you would put the item into the cache for the first time: 1: public sealed class PriceCache 2: { 3: private readonly ConcurrentDictionary<string, double> _cache = new ConcurrentDictionary<string, double>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public double QueryPrice(string tickerKey) 7: { 8: // check for the price in the cache, if it doesn't exist it will call the delegate to create value. 9: return _cache.GetOrAdd(tickerKey, symbol => GetCurrentPrice(symbol)); 10: } 11:  12: private double GetCurrentPrice(string tickerKey) 13: { 14: // do code to calculate actual true price. 15: } 16: } There are other variations of these two methods which vary whether a value is provided or a factory delegate, but otherwise they work much the same. Oddities with the composite Add methods The AddOrUpdate() and GetOrAdd() methods are totally thread-safe, on this you may rely, but they are not atomic.  It is important to note that the methods that use delegates execute those delegates outside of the lock.  This was done intentionally so that a user delegate (of which the ConcurrentDictionary has no control of course) does not take too long and lock out other threads. This is not necessarily an issue, per se, but it is something you must consider in your design.  The main thing to consider is that your delegate may get called to generate an item, but that item may not be the one returned!  Consider this scenario: A calls GetOrAdd and sees that the key does not currently exist, so it calls the delegate.  Now thread B also calls GetOrAdd and also sees that the key does not currently exist, and for whatever reason in this race condition it’s delegate completes first and it adds its new value to the dictionary.  Now A is done and goes to get the lock, and now sees that the item now exists.  In this case even though it called the delegate to create the item, it will pitch it because an item arrived between the time it attempted to create one and it attempted to add it. Let’s illustrate, assume this totally contrived example program which has a dictionary of char to int.  And in this dictionary we want to store a char and it’s ordinal (that is, A = 1, B = 2, etc).  So for our value generator, we will simply increment the previous value in a thread-safe way (perhaps using Interlocked): 1: public static class Program 2: { 3: private static int _nextNumber = 0; 4:  5: // the holder of the char to ordinal 6: private static ConcurrentDictionary<char, int> _dictionary 7: = new ConcurrentDictionary<char, int>(); 8:  9: // get the next id value 10: public static int NextId 11: { 12: get { return Interlocked.Increment(ref _nextNumber); } 13: } Then, we add a method that will perform our insert: 1: public static void Inserter() 2: { 3: for (int i = 0; i < 26; i++) 4: { 5: _dictionary.GetOrAdd((char)('A' + i), key => NextId); 6: } 7: } Finally, we run our test by starting two tasks to do this work and get the results… 1: public static void Main() 2: { 3: // 3 tasks attempting to get/insert 4: var tasks = new List<Task> 5: { 6: new Task(Inserter), 7: new Task(Inserter) 8: }; 9:  10: tasks.ForEach(t => t.Start()); 11: Task.WaitAll(tasks.ToArray()); 12:  13: foreach (var pair in _dictionary.OrderBy(p => p.Key)) 14: { 15: Console.WriteLine(pair.Key + ":" + pair.Value); 16: } 17: } If you run this with only one task, you get the expected A:1, B:2, ..., Z:26.  But running this in parallel you will get something a bit more complex.  My run netted these results: 1: A:1 2: B:3 3: C:4 4: D:5 5: E:6 6: F:7 7: G:8 8: H:9 9: I:10 10: J:11 11: K:12 12: L:13 13: M:14 14: N:15 15: O:16 16: P:17 17: Q:18 18: R:19 19: S:20 20: T:21 21: U:22 22: V:23 23: W:24 24: X:25 25: Y:26 26: Z:27 Notice that B is 3?  This is most likely because both threads attempted to call GetOrAdd() at roughly the same time and both saw that B did not exist, thus they both called the generator and one thread got back 2 and the other got back 3.  However, only one of those threads can get the lock at a time for the actual insert, and thus the one that generated the 3 won and the 3 was inserted and the 2 got discarded.  This is why on these methods your factory delegates should be careful not to have any logic that would be unsafe if the value they generate will be pitched in favor of another item generated at roughly the same time.  As such, it is probably a good idea to keep those generators as stateless as possible. Summary The ConcurrentDictionary is a very efficient and thread-safe version of the Dictionary generic collection.  It has all the benefits of type-safety that it’s generic collection counterpart does, and in addition is extremely efficient especially when there are more reads than writes concurrently. Tweet Technorati Tags: C#, .NET, Concurrent Collections, Collections, Little Wonders, Black Rabbit Coder,James Michael Hare

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• webserver horrible slow, sometimes incredible fast

  - by dhanke

  i am running a small community ( 6000+ Members ) on a non-virtual 64-bit ubuntu 11.04 system. I am not a Linux-pro, not even advanced, i just tried to setup a webserver, which does nothing special actually. Delivering some dynamic PHP and RoR websites is its task. So it might be that my configuration files do look horrible bad. Also, i might use the wrong vocabulary, so in doubt, please ask. Having a current all-time record of 520 registered users (board-accounts, no system-users) online at same time, average server-load is about 2.0 - 5.0. Meantime (~250 users) average server load value is at about 0.4 - 0.8, sometimes, on some expensive searches a bit higher. everything fine. From time to time however, the load increases up to 120 (120.0, not 12.0 ;) ). In this time, its hard to even connect via SSH, but when i reach the server, and use top/htop/iotop to see whats happening, i cannot identify any process causing high CPU load. iotop tells me about a current reading/writing speed of about approx. 70kb/s, which is quite equal to power-off i think. Memory-Usage is max. at ~ 12GB of 16GB, so swap remains empty. now the odd (at least for me:) waiting some minutes ( since i always get a bit into a panic when this happens, it feels like 5 minutes, but i suppose its more like 20-30 minutes) and the server is back to normal. everything continues as normal. another odd fact: when i run hdparm -tT /dev/sda, i get answer like: /dev/sda: Timing cached reads: 7180 MB in 2.00 seconds = 3591.13 MB/sec Timing buffered disk reads: 348 MB in 3.02 seconds = 115.41 MB/sec when i run the same command while the server is "frozen", the answer is like /dev/sda: <- takes about 5 minutes until this line appears Timing cached reads: 7180 MB in 2.00 seconds = 3591.13 MB/sec <- 5 more minutes Timing buffered disk reads: 348 MB in 3.02 seconds = 115.41 MB/sec <- another 5 minutes so the values are the same, but the quoted time is completely wrong. using time command as prefix also tells me that ~ 15 minutes were used. I searched in dmesg, /var/log/[messages|syslog] - nothing found. /var/log/errors however tells me that: Jul 4 20:28:30 localhost kernel: [19080.671415] INFO: task php5-fpm:27728 blocked for more than 120 seconds. Jul 4 20:28:30 localhost kernel: [19080.671419] "echo 0 /proc/sys/kernel/hung_task_timeout_secs" disables this message. multiple times. now that message does tell me that php5-fpm task was blocked or did block ? - but not if that is the cause or just one of the results of that "freeze". Anyone? to cut the long story short, i dont know where even to start analyzing. So if you can give me any advice by looking at following specs and configs, or ask me to provide more information, i`d be glad. Specs: 6 Core AMD Phenom(tm) II X6 1055T Processor * 16 Gigabyte Ram 2x 1.5 TB Seagate ST1500DL003-9VT16L via SATA 3 via SoftwareRaid (i suppose) Services: (due to service --status-all, those with [ + ]) nginx Webserver 1.0.14 mySQL 5.1.63 Server Ruby on Rails 2.3.11 ( passenger-nginx-module ) php5-fpm 5.3.6-13ubuntu3.7 SSH ido2db Further services: default crontab + nightly backup. syslog-ng Website consists of 2 subdomains, forum. and www. where forum is a phpBB3.x PHP-Board, and www a Ruby on Rails 2.3.11 application (portal). Mini-Note: sometimes i notice that the forum is pretty slow, in contrast to the always-fast (except for this "freeze") portal. Both share the same Database, but the portal is using it read-only. The Webserver is nginx, using phusion passenger module to communicate with the ruby-application. Also, for the forum it communicates with php5-fpm via socket: relevant nginx configuration parts ( with comments/questions starting by ; ) ; in case of freeze due to too high Filesystem activity, maybe adding a limit? #worker_rlimit_nofile 50000; user www-data; ; 6 cores, so i read 6 fits. maybe already wrong? worker_processes 6; pid /var/run/nginx.pid; events { worker_connections 1024; } http { passenger_root /var/lib/gems/1.8/gems/passenger-3.0.11; passenger_ruby /usr/bin/ruby1.8; ; the forum once featured a chat, which was working w/o websockets. ; so it was a hell of pull requests (deactivated now, freeze still happening) keepalive_timeout 65; keepalive_requests 50; gzip on; server { listen 80; server_name www.domain.tld; root /var/www/domain/rails/public; passenger_enabled on; } server { listen 80; server_name forum.domain.tld; location / { root /var/www/domain/forum; index index.php; } ; satic stuff to be handled by nginx location ~* ^/style/.+.(jpg|jpeg|gif|css|png|js|ico|xml)$ { access_log off; expires 30d; root /var/www/domain/forum/; } ; now the php magic, note the "backend"-fcgi_pass location ~ .php$ { fastcgi_split_path_info ^(.+\.php)(.*)$; fastcgi_pass backend; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME /var/www/domain/forum$fastcgi_script_name; include fastcgi_params; fastcgi_param QUERY_STRING $query_string; fastcgi_param REQUEST_METHOD $request_method; fastcgi_param CONTENT_TYPE $content_type; fastcgi_param CONTENT_LENGTH $content_length; fastcgi_intercept_errors on; fastcgi_ignore_client_abort off; fastcgi_connect_timeout 60; fastcgi_send_timeout 180; fastcgi_read_timeout 180; fastcgi_buffer_size 128k; fastcgi_buffers 256 16k; fastcgi_busy_buffers_size 256k; fastcgi_temp_file_write_size 256k; fastcgi_max_temp_file_size 0; } location ~ /\.ht { deny all; } } ;the php5-fpm socket. i read that /dev/shm/ whould be the fastes place for this. bad idea in general? upstream backend { server unix:/dev/shm/phpfpm; } ... } php5-fpm settings (i changed this values due to php5-fpm error log messages higher and higher.. (freeze-problem was there before as well)* listen = /dev/shm/phpfpm user = www-data group = www-data pm = dynamic ; holy, 4000! well, shinking this value to earth-level gave me ; 100s of 502 bad gateway commands. this values were quite stable. ; since there are only max 520 users online i dont get it, why i would need ; as many children as configured here. due to keep-alive maybe? ; asking questions is easier for me since restarting server will make ; my community-members angry ;) pm.max_children = 4000 pm.start_servers = 100 pm.min_spare_servers = 50 pm.max_spare_servers = 150 pm.max_requests = 10 pm.status_path = /status ping.path = /ping ping.response = pong slowlog = log/$pool.log.slow ;should i use rlimit? ;rlimit_files = 1024 chdir = / mysql/my.cnf [client] port = 3306 socket = /var/run/mysqld/mysqld.sock [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp skip-external-locking bind-address = 127.0.0.1 key_buffer = 16M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 myisam-recover = BACKUP ; high number, but less gives some phpBB errors. max_connections = 450 table_cache = 512 ; i read twice the cpu cores, bad? thread_concurrency = 12 join_buffer_size = 2084K concurrent_insert = 3 query_cache_limit = 64M query_cache_size = 512M query_cache_type = 1 log_error = /var/log/mysql/error.log log_slow_queries = /var/log/mysql/mysql-slow.log long_query_time = 2 expire_logs_days = 10 max_binlog_size = 100M low_priority_updates=1 [mysqldump] quick quote-names max_allowed_packet = 16M [isamchk] key_buffer = 16M !includedir /etc/mysql/conf.d/ I used smartctl already, hdds seem to be fine. /proc/mdstatus quotes: Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md3 : active raid1 sda3[1] 1459264192 blocks [2/1] [_U] md1 : active raid1 sda1[0] 3911680 blocks [2/1] [U_] unused devices: ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 127727 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 127727 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited I quote some questions in my configuration files, these are not (intentional) directly problem-related, but would be nice for me to know wether they are indeed questionable or done right. One additional Fact: my MYSQL-database is at 12GB size. i dont know if that does matter, but mytop sometimes shows me 4-5 seconds long insert queries, some are 20-30 seconds long. Its just a feeling that i am unable to prove (because i dont know how), but when i disable the database, the freeze seems not to happen. Example: i created a dummy rails application to see the development log. the app made some sql-queries, reads and inserts. the log quite often was like: DbTest Load (0.3ms) SELECT * FROM `db_test` WHERE (`db_test`.`id` = 31722) LIMIT 1 SQL (0.1ms) BEGIN DbTest Update (0.3ms) UPDATE `db_test` SET `updated_at` = '2012-07-04 23:32:34' WHERE `id` = 31722 - now the log stands still for 5-60 seconds. SQL (49.1ms) COMMIT - SQL-Update time in the log does not include freeze time Rendering test/index Completed in 96ms (View: 16, DB: 59) | 200 OK [http://localhost:9000/test] Bad part is: this mini-freeze here only happens from time to time as well. note: meanwhile i cannot even upload files via scp. I currently feel like running form bad to worse and back by googling for my server-problem due to immense lack of knowledge regarding server configurations. It still makes me wonder, why those problems even appear, since 250 users a time is not such a high amount, right? So my questions: whats wrong and how to fix? ;) or: what information can i provide to make the situation more clear? can you point at some critical bad configuration-line which i should consider to catch up in the documentation? are there any tools i can run to see some possible bottlenecks? any further advice? (next to: "pay someone who knows what he does" - its a private project, server costs enough already. :)) Thanks for your time and help. Best Regards, Daniel P.S.: i renamed the configfiles to domain.tld since i dont want to have any % more load to the server until its fixed. might be a exaggeratedly thought.. P.P.S: if i asked a complete duplicate question, sorry. my search results seemed to be quite specific in their own way.

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• Red Gate Coder interviews: Alex Davies

  - by Michael Williamson

  Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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• OpenLDAP and SSL

  - by Stormshadow

  I am having trouble trying to connect to a secure OpenLDAP server which I have set up. On running my LDAP client code java -Djavax.net.debug=ssl LDAPConnector I get the following exception trace (java version 1.6.0_17) trigger seeding of SecureRandom done seeding SecureRandom %% No cached client session *** ClientHello, TLSv1 RandomCookie: GMT: 1256110124 bytes = { 224, 19, 193, 148, 45, 205, 108, 37, 101, 247, 112, 24, 157, 39, 111, 177, 43, 53, 206, 224, 68, 165, 55, 185, 54, 203, 43, 91 } Session ID: {} Cipher Suites: [SSL_RSA_WITH_RC4_128_MD5, SSL_RSA_WITH_RC4_128_SHA, TLS_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_DSS_WITH_AES_128_CBC_SHA, SSL_RSA_W ITH_3DES_EDE_CBC_SHA, SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA, SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA, SSL_RSA_WITH_DES_CBC_SHA, SSL_DHE_RSA_WITH_DES_CBC_SHA, SSL_DHE_DSS_WITH_DES_CBC_SH A, SSL_RSA_EXPORT_WITH_RC4_40_MD5, SSL_RSA_EXPORT_WITH_DES40_CBC_SHA, SSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA, SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA] Compression Methods: { 0 } *** Thread-0, WRITE: TLSv1 Handshake, length = 73 Thread-0, WRITE: SSLv2 client hello message, length = 98 Thread-0, received EOFException: error Thread-0, handling exception: javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake Thread-0, SEND TLSv1 ALERT: fatal, description = handshake_failure Thread-0, WRITE: TLSv1 Alert, length = 2 Thread-0, called closeSocket() main, handling exception: javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake javax.naming.CommunicationException: simple bind failed: ldap.natraj.com:636 [Root exception is javax.net.ssl.SSLHandshakeException: Remote host closed connection during hands hake] at com.sun.jndi.ldap.LdapClient.authenticate(Unknown Source) at com.sun.jndi.ldap.LdapCtx.connect(Unknown Source) at com.sun.jndi.ldap.LdapCtx.<init>(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getUsingURL(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getUsingURLs(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxInstance(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getInitialContext(Unknown Source) at javax.naming.spi.NamingManager.getInitialContext(Unknown Source) at javax.naming.InitialContext.getDefaultInitCtx(Unknown Source) at javax.naming.InitialContext.init(Unknown Source) at javax.naming.InitialContext.<init>(Unknown Source) at javax.naming.directory.InitialDirContext.<init>(Unknown Source) at LDAPConnector.CallSecureLDAPServer(LDAPConnector.java:43) at LDAPConnector.main(LDAPConnector.java:237) Caused by: javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(Unknown Source) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readDataRecord(Unknown Source) at com.sun.net.ssl.internal.ssl.AppInputStream.read(Unknown Source) at java.io.BufferedInputStream.fill(Unknown Source) at java.io.BufferedInputStream.read1(Unknown Source) at java.io.BufferedInputStream.read(Unknown Source) at com.sun.jndi.ldap.Connection.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.io.EOFException: SSL peer shut down incorrectly at com.sun.net.ssl.internal.ssl.InputRecord.read(Unknown Source) ... 9 more I am able to connect to the same secure LDAP server however if I use another version of java (1.6.0_14) I have created and installed the server certificates in the cacerts of both the JRE's as mentioned in this guide -- OpenLDAP with SSL When I run ldapsearch -x on the server I get # extended LDIF # # LDAPv3 # base <dc=localdomain> (default) with scope subtree # filter: (objectclass=*) # requesting: ALL # # localdomain dn: dc=localdomain objectClass: top objectClass: dcObject objectClass: organization o: localdomain dc: localdomain # admin, localdomain dn: cn=admin,dc=localdomain objectClass: simpleSecurityObject objectClass: organizationalRole cn: admin description: LDAP administrator # search result search: 2 result: 0 Success # numResponses: 3 # numEntries: 2 On running openssl s_client -connect ldap.natraj.com:636 -showcerts , I obtain the self signed certificate. My slapd.conf file is as follows ####################################################################### # Global Directives: # Features to permit #allow bind_v2 # Schema and objectClass definitions include /etc/ldap/schema/core.schema include /etc/ldap/schema/cosine.schema include /etc/ldap/schema/nis.schema include /etc/ldap/schema/inetorgperson.schema # Where the pid file is put. The init.d script # will not stop the server if you change this. pidfile /var/run/slapd/slapd.pid # List of arguments that were passed to the server argsfile /var/run/slapd/slapd.args # Read slapd.conf(5) for possible values loglevel none # Where the dynamically loaded modules are stored modulepath /usr/lib/ldap moduleload back_hdb # The maximum number of entries that is returned for a search operation sizelimit 500 # The tool-threads parameter sets the actual amount of cpu's that is used # for indexing. tool-threads 1 ####################################################################### # Specific Backend Directives for hdb: # Backend specific directives apply to this backend until another # 'backend' directive occurs backend hdb ####################################################################### # Specific Backend Directives for 'other': # Backend specific directives apply to this backend until another # 'backend' directive occurs #backend <other> ####################################################################### # Specific Directives for database #1, of type hdb: # Database specific directives apply to this databasse until another # 'database' directive occurs database hdb # The base of your directory in database #1 suffix "dc=localdomain" # rootdn directive for specifying a superuser on the database. This is needed # for syncrepl. rootdn "cn=admin,dc=localdomain" # Where the database file are physically stored for database #1 directory "/var/lib/ldap" # The dbconfig settings are used to generate a DB_CONFIG file the first # time slapd starts. They do NOT override existing an existing DB_CONFIG # file. You should therefore change these settings in DB_CONFIG directly # or remove DB_CONFIG and restart slapd for changes to take effect. # For the Debian package we use 2MB as default but be sure to update this # value if you have plenty of RAM dbconfig set_cachesize 0 2097152 0 # Sven Hartge reported that he had to set this value incredibly high # to get slapd running at all. See http://bugs.debian.org/303057 for more # information. # Number of objects that can be locked at the same time. dbconfig set_lk_max_objects 1500 # Number of locks (both requested and granted) dbconfig set_lk_max_locks 1500 # Number of lockers dbconfig set_lk_max_lockers 1500 # Indexing options for database #1 index objectClass eq # Save the time that the entry gets modified, for database #1 lastmod on # Checkpoint the BerkeleyDB database periodically in case of system # failure and to speed slapd shutdown. checkpoint 512 30 # Where to store the replica logs for database #1 # replogfile /var/lib/ldap/replog # The userPassword by default can be changed # by the entry owning it if they are authenticated. # Others should not be able to see it, except the # admin entry below # These access lines apply to database #1 only access to attrs=userPassword,shadowLastChange by dn="cn=admin,dc=localdomain" write by anonymous auth by self write by * none # Ensure read access to the base for things like # supportedSASLMechanisms. Without this you may # have problems with SASL not knowing what # mechanisms are available and the like. # Note that this is covered by the 'access to *' # ACL below too but if you change that as people # are wont to do you'll still need this if you # want SASL (and possible other things) to work # happily. access to dn.base="" by * read # The admin dn has full write access, everyone else # can read everything. access to * by dn="cn=admin,dc=localdomain" write by * read # For Netscape Roaming support, each user gets a roaming # profile for which they have write access to #access to dn=".*,ou=Roaming,o=morsnet" # by dn="cn=admin,dc=localdomain" write # by dnattr=owner write ####################################################################### # Specific Directives for database #2, of type 'other' (can be hdb too): # Database specific directives apply to this databasse until another # 'database' directive occurs #database <other> # The base of your directory for database #2 #suffix "dc=debian,dc=org" ####################################################################### # SSL: # Uncomment the following lines to enable SSL and use the default # snakeoil certificates. #TLSCertificateFile /etc/ssl/certs/ssl-cert-snakeoil.pem #TLSCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key TLSCipherSuite TLS_RSA_AES_256_CBC_SHA TLSCACertificateFile /etc/ldap/ssl/server.pem TLSCertificateFile /etc/ldap/ssl/server.pem TLSCertificateKeyFile /etc/ldap/ssl/server.pem My ldap.conf file is # # LDAP Defaults # # See ldap.conf(5) for details # This file should be world readable but not world writable. HOST ldap.natraj.com PORT 636 BASE dc=localdomain URI ldaps://ldap.natraj.com TLS_CACERT /etc/ldap/ssl/server.pem TLS_REQCERT allow #SIZELIMIT 12 #TIMELIMIT 15 #DEREF never

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• Silverlight 4 + WCF RIA - Data Service Design Best Practices

  - by Chadd Nervig

  Hey all. I realize this is a rather long question, but I'd really appreciate any help from anyone experienced with RIA services. Thanks! I'm working on a Silverlight 4 app that views data from the server. I'm relatively inexperienced with RIA Services, so have been working through the tasks of getting the data I need down to the client, but every new piece I add to the puzzle seems to be more and more problematic. I feel like I'm missing some basic concepts here, and it seems like I'm just 'hacking' pieces on, in time-consuming ways, each one breaking the previous ones as I try to add them. I'd love to get the feedback of developers experienced with RIA services, to figure out the intended way to do what I'm trying to do. Let me lay out what I'm trying to do: First, the data. The source of this data is a variety of sources, primarily created by a shared library which reads data from our database, and exposes it as POCOs (Plain Old CLR Objects). I'm creating my own POCOs to represent the different types of data I need to pass between server and client. DataA - This app is for viewing a certain type of data, lets call DataA, in near-realtime. Every 3 minutes, the client should pull data down from the server, of all the new DataA since the last time it requested data. DataB - Users can view the DataA objects in the app, and may select one of them from the list, which displays additional details about that DataA. I'm bringing these extra details down from the server as DataB. DataC - One of the things that DataB contains is a history of a couple important values over time. I'm calling each data point of this history a DataC object, and each DataB object contains many DataCs. The Data Model - On the server side, I have a single DomainService: [EnableClientAccess] public class MyDomainService : DomainService { public IEnumerable<DataA> GetDataA(DateTime? startDate) { /*Pieces together the DataAs that have been created since startDate, and returns them*/ } public DataB GetDataB(int dataAID) { /*Looks up the extended info for that dataAID, constructs a new DataB with that DataA's data, plus the extended info (with multiple DataCs in a List<DataC> property on the DataB), and returns it*/ } //Not exactly sure why these are here, but I think it //wouldn't compile without them for some reason? The data //is entirely read-only, so I don't need to update. public void UpdateDataA(DataA dataA) { throw new NotSupportedException(); } public void UpdateDataB(DataB dataB) { throw new NotSupportedException(); } } The classes for DataA/B/C look like this: [KnownType(typeof(DataB))] public partial class DataA { [Key] [DataMember] public int DataAID { get; set; } [DataMember] public decimal MyDecimalA { get; set; } [DataMember] public string MyStringA { get; set; } [DataMember] public DataTime MyDateTimeA { get; set; } } public partial class DataB : DataA { [Key] [DataMember] public int DataAID { get; set; } [DataMember] public decimal MyDecimalB { get; set; } [DataMember] public string MyStringB { get; set; } [Include] //I don't know which of these, if any, I need? [Composition] [Association("DataAToC","DataAID","DataAID")] public List<DataC> DataCs { get; set; } } public partial class DataC { [Key] [DataMember] public int DataAID { get; set; } [Key] [DataMember] public DateTime Timestamp { get; set; } [DataMember] public decimal MyHistoricDecimal { get; set; } } I guess a big question I have here is... Should I be using Entities instead of POCOs? Are my classes constructed correctly to be able to pass the data down correctly? Should I be using Invoke methods instead of Query (Get) methods on the DomainService? On the client side, I'm having a number of issues. Surprisingly, one of my biggest ones has been threading. I didn't expect there to be so many threading issues with MyDomainContext. What I've learned is that you only seem to be able to create MyDomainContextObjects on the UI thread, all of the queries you can make are done asynchronously only, and that if you try to fake doing it synchronously by blocking the calling thread until the LoadOperation finishes, you have to do so on a background thread, since it uses the UI thread to make the query. So here's what I've got so far. The app should display a stream of the DataA objects, spreading each 3min chunk of them over the next 3min (so they end up displayed 3min after the occurred, looking like a continuous stream, but only have to be downloaded in 3min bursts). To do this, the main form initializes, creates a private MyDomainContext, and starts up a background worker, which continuously loops in a while(true). On each loop, it checks if it has any DataAs left over to display. If so, it displays that Data, and Thread.Sleep()s until the next DataA is scheduled to be displayed. If it's out of data, it queries for more, using the following methods: public DataA[] GetDataAs(DateTime? startDate) { _loadOperationGetDataACompletion = new AutoResetEvent(false); LoadOperation<DataA> loadOperationGetDataA = null; loadOperationGetDataA = _context.Load(_context.GetDataAQuery(startDate), System.ServiceModel.DomainServices.Client.LoadBehavior.RefreshCurrent, false); loadOperationGetDataA.Completed += new EventHandler(loadOperationGetDataA_Completed); _loadOperationGetDataACompletion.WaitOne(); List<DataA> dataAs = new List<DataA>(); foreach (var dataA in loadOperationGetDataA.Entities) dataAs.Add(dataA); return dataAs.ToArray(); } private static AutoResetEvent _loadOperationGetDataACompletion; private static void loadOperationGetDataA_Completed(object sender, EventArgs e) { _loadOperationGetDataACompletion.Set(); } Seems kind of clunky trying to force it into being synchronous, but since this already is on a background thread, I think this is OK? So far, everything actually works, as much of a hack as it seems like it may be. It's important to note that if I try to run that code on the UI thread, it locks, because it waits on the WaitOne() forever, locking the thread, so it can't make the Load request to the server. So once the data is displayed, users can click on one as it goes by to fill a details pane with the full DataB data about that object. To do that, I have the the details pane user control subscribing to a selection event I have setup, which gets fired when the selection changes (on the UI thread). I use a similar technique there, to get the DataB object: void SelectionService_SelectedDataAChanged(object sender, EventArgs e) { DataA dataA = /*Get the selected DataA*/; MyDomainContext context = new MyDomainContext(); var loadOperationGetDataB = context.Load(context.GetDataBQuery(dataA.DataAID), System.ServiceModel.DomainServices.Client.LoadBehavior.RefreshCurrent, false); loadOperationGetDataB.Completed += new EventHandler(loadOperationGetDataB_Completed); } private void loadOperationGetDataB_Completed(object sender, EventArgs e) { this.DataContext = ((LoadOperation<DataB>)sender).Entities.SingleOrDefault(); } Again, it seems kinda hacky, but it works... except on the DataB that it loads, the DataCs list is empty. I've tried all kinds of things there, and I don't see what I'm doing wrong to allow the DataCs to come down with the DataB. I'm about ready to make a 3rd query for the DataCs, but that's screaming even more hackiness to me. It really feels like I'm fighting against the grain here, like I'm doing this in an entirely unintended way. If anyone could offer any assistance, and point out what I'm doing wrong here, I'd very much appreciate it! Thanks!

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• Authoritative sources about Database vs. Flatfile decision

  - by FastAl

  <tldr>looking for a reference to a book or other undeniably authoritative source that gives reasons when you should choose a database vs. when you should choose other storage methods. I have provided an un-authoritative list of reasons about 2/3 of the way down this post.</tldr> I have a situation at my company where a database is being used where it would be better to use another solution (in this case, an auto-generated piece of source code that contains a static lookup table, searched by binary sort). Normally, a database would be an OK solution even though the problem does not require a database, e.g, none of the elements of ACID are needed, as it is read-only data, updated about every 3-5 years (also requiring other sourcecode changes), and fits in memory, and can be keyed into via binary search (a tad faster than db, but speed is not an issue). The problem is that this code runs on our enterprise server, but is shared with several PC platforms (some disconnected, some use a central DB, etc.), and parts of it are managed by multiple programming units, parts by the DBAs, parts even by mathematicians in another department, etc. These hit their own platform’s version of their databases (containing their own copy of the static data). What happens is that every implementation, every little change, something different goes wrong. There are many other issues as well. I can’t even use a flatfile, because one mode of running on our enterprise server does not have permission to read files (only databases, and of course, its own literal storage, e.g., in-source table). Of course, other parts of the system use databases in proper, less obscure manners; there is no problem with those parts. So why don’t we just change it? I don’t have administrative ability to force a change. But I’m affected because sometimes I have to help fix the problems, but mostly because it causes outages and tons of extra IT time by other programmers and d*mmit that makes me mad! The reason neither management, nor the designers of the system, can see the problem is that they propose a solution that won’t work: increase communication; implement more safeguards and standards; etc. But every time, in a different part of the already-pared-down but still multi-step processes, a few different diligent, hard-working, top performing IT personnel make a unique subtle error that causes it to fail, sometimes after the last round of testing! And in general these are not single-person failures, but understandable miscommunications. And communication at our company is actually better than most. People just don't think that's the case because they haven't dug into the matter. However, I have it on very good word from somebody with extensive formal study of sociology and psychology that the relatively small amount of less-than-proper database usage in this gigantic cross-platform multi-source, multi-language project is bureaucratically un-maintainable. Impossible. No chance. At least with Human Beings in the loop, and it can’t be automated. In addition, the management and developers who could change this, though intelligent and capable, don’t understand the rigidity of this ‘how humans are’ issue, and are not convincible on the matter. The reason putting the static data in sourcecode will solve the problem is, although the solution is less sexy than a database, it would function with no technical drawbacks; and since the sharing of sourcecode already works very well, you basically erase any database-related effort from this section of the project, along with all the drawbacks of it that are causing problems. OK, that’s the background, for the curious. I won’t be able to convince management that this is an unfixable sociological problem, and that the real solution is coding around these limits of human nature, just as you would code around a bug in a 3rd party component that you can’t change. So what I have to do is exploit the unsuitableness of the database solution, and not do it using logic, but rather authority. I am aware of many reasons, and posts on this site giving reasons for one over the other; I’m not looking for lists of reasons like these (although you can add a comment if I've miss a doozy): WHY USE A DATABASE? instead of flatfile/other DB vs. file: if you need... Random Read / Transparent search optimization Advanced / varied / customizable Searching and sorting capabilities Transaction/rollback Locks, semaphores Concurrency control / Shared users Security 1-many/m-m is easier Easy modification Scalability Load Balancing Random updates / inserts / deletes Advanced query Administrative control of design, etc. SQL / learning curve Debugging / Logging Centralized / Live Backup capabilities Cached queries / dvlp & cache execution plans Interleaved update/read Referential integrity, avoid redundant/missing/corrupt/out-of-sync data Reporting (from on olap or oltp db) / turnkey generation tools [Disadvantages:] Important to get right the first time - professional design - but only b/c it's meant to last s/w & h/w cost Usu. over a network, speed issue (best vs. best design vs. local=even then a separate process req's marshalling/netwk layers/inter-p comm) indicies and query processing can stand in the way of simple processing (vs. flatfile) WHY USE FLATFILE: If you only need... Sequential Row processing only Limited usage append only (no reading, no master key/update) Only Update the record you're reading (fixed length recs only) Too big to fit into memory If Local disk / read-ahead network connection Portability / small system Email / cut & Paste / store as document by novice - simple format Low design learning curve but high cost later WHY USE IN-MEMORY/TABLE (tables, arrays, etc.): if you need... Processing a single db/ff record that was imported Known size of data Static data if hardcoding the table Narrow, unchanging use (e.g., one program or proc) -includes a class that will be shared, but encapsulates its data manipulation Extreme speed needed / high transaction frequency Random access - but search is dependent on implementation Following are some other posts about the topic: http://stackoverflow.com/questions/1499239/database-vs-flat-text-file-what-are-some-technical-reasons-for-choosing-one-over http://stackoverflow.com/questions/332825/are-flat-file-databases-any-good http://stackoverflow.com/questions/2356851/database-vs-flat-files http://stackoverflow.com/questions/514455/databases-vs-plain-text/514530 What I’d like to know is if anybody could recommend a hard, authoritative source containing these reasons. I’m looking for a paper book I can buy, or a reputable website with whitepapers about the issue (e.g., Microsoft, IBM), not counting the user-generated content on those sites. This will have a greater change to elicit a change that I’m looking for: less wasted programmer time, and more reliable programs. Thanks very much for your help. You win a prize for reading such a large post!

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• How do I prove I should put a table of values in source code instead of a database table?

  - by FastAl

  <tldr>looking for a reference to a book or other undeniably authoritative source that gives reasons when you should choose a database vs. when you should choose other storage methods. I have provided an un-authoritative list of reasons about 2/3 of the way down this post.</tldr> I have a situation at my company where a database is being used where it would be better to use another solution (in this case, an auto-generated piece of source code that contains a static lookup table, searched by binary sort). Normally, a database would be an OK solution even though the problem does not require a database, e.g, none of the elements of ACID are needed, as it is read-only data, updated about every 3-5 years (also requiring other sourcecode changes), and fits in memory, and can be keyed into via binary search (a tad faster than db, but speed is not an issue). The problem is that this code runs on our enterprise server, but is shared with several PC platforms (some disconnected, some use a central DB, etc.), and parts of it are managed by multiple programming units, parts by the DBAs, parts even by mathematicians in another department, etc. These hit their own platform’s version of their databases (containing their own copy of the static data). What happens is that every implementation, every little change, something different goes wrong. There are many other issues as well. I can’t even use a flatfile, because one mode of running on our enterprise server does not have permission to read files (only databases, and of course, its own literal storage, e.g., in-source table). Of course, other parts of the system use databases in proper, less obscure manners; there is no problem with those parts. So why don’t we just change it? I don’t have administrative ability to force a change. But I’m affected because sometimes I have to help fix the problems, but mostly because it causes outages and tons of extra IT time by other programmers and d*mmit that makes me mad! The reason neither management, nor the designers of the system, can see the problem is that they propose a solution that won’t work: increase communication; implement more safeguards and standards; etc. But every time, in a different part of the already-pared-down but still multi-step processes, a few different diligent, hard-working, top performing IT personnel make a unique subtle error that causes it to fail, sometimes after the last round of testing! And in general these are not single-person failures, but understandable miscommunications. And communication at our company is actually better than most. People just don't think that's the case because they haven't dug into the matter. However, I have it on very good word from somebody with extensive formal study of sociology and psychology that the relatively small amount of less-than-proper database usage in this gigantic cross-platform multi-source, multi-language project is bureaucratically un-maintainable. Impossible. No chance. At least with Human Beings in the loop, and it can’t be automated. In addition, the management and developers who could change this, though intelligent and capable, don’t understand the rigidity of this ‘how humans are’ issue, and are not convincible on the matter. The reason putting the static data in sourcecode will solve the problem is, although the solution is less sexy than a database, it would function with no technical drawbacks; and since the sharing of sourcecode already works very well, you basically erase any database-related effort from this section of the project, along with all the drawbacks of it that are causing problems. OK, that’s the background, for the curious. I won’t be able to convince management that this is an unfixable sociological problem, and that the real solution is coding around these limits of human nature, just as you would code around a bug in a 3rd party component that you can’t change. So what I have to do is exploit the unsuitableness of the database solution, and not do it using logic, but rather authority. I am aware of many reasons, and posts on this site giving reasons for one over the other; I’m not looking for lists of reasons like these (although you can add a comment if I've miss a doozy): WHY USE A DATABASE? instead of flatfile/other DB vs. file: if you need... Random Read / Transparent search optimization Advanced / varied / customizable Searching and sorting capabilities Transaction/rollback Locks, semaphores Concurrency control / Shared users Security 1-many/m-m is easier Easy modification Scalability Load Balancing Random updates / inserts / deletes Advanced query Administrative control of design, etc. SQL / learning curve Debugging / Logging Centralized / Live Backup capabilities Cached queries / dvlp & cache execution plans Interleaved update/read Referential integrity, avoid redundant/missing/corrupt/out-of-sync data Reporting (from on olap or oltp db) / turnkey generation tools [Disadvantages:] Important to get right the first time - professional design - but only b/c it's meant to last s/w & h/w cost Usu. over a network, speed issue (best vs. best design vs. local=even then a separate process req's marshalling/netwk layers/inter-p comm) indicies and query processing can stand in the way of simple processing (vs. flatfile) WHY USE FLATFILE: If you only need... Sequential Row processing only Limited usage append only (no reading, no master key/update) Only Update the record you're reading (fixed length recs only) Too big to fit into memory If Local disk / read-ahead network connection Portability / small system Email / cut & Paste / store as document by novice - simple format Low design learning curve but high cost later WHY USE IN-MEMORY/TABLE (tables, arrays, etc.): if you need... Processing a single db/ff record that was imported Known size of data Static data if hardcoding the table Narrow, unchanging use (e.g., one program or proc) -includes a class that will be shared, but encapsulates its data manipulation Extreme speed needed / high transaction frequency Random access - but search is dependent on implementation Following are some other posts about the topic: http://stackoverflow.com/questions/1499239/database-vs-flat-text-file-what-are-some-technical-reasons-for-choosing-one-over http://stackoverflow.com/questions/332825/are-flat-file-databases-any-good http://stackoverflow.com/questions/2356851/database-vs-flat-files http://stackoverflow.com/questions/514455/databases-vs-plain-text/514530 What I’d like to know is if anybody could recommend a hard, authoritative source containing these reasons. I’m looking for a paper book I can buy, or a reputable website with whitepapers about the issue (e.g., Microsoft, IBM), not counting the user-generated content on those sites. This will have a greater change to elicit a change that I’m looking for: less wasted programmer time, and more reliable programs. Thanks very much for your help. You win a prize for reading such a large post!

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• socket operation on nonsocket or bad file descriptor

  - by Magn3s1um

  I'm writing a pthread server which takes requests from clients and sends them back a bunch of .ppm files. Everything seems to go well, but sometimes when I have just 1 client connected, when trying to read from the file descriptor (for the file), it says Bad file Descriptor. This doesn't make sense, since my int fd isn't -1, and the file most certainly exists. Other times, I get this "Socket operation on nonsocket" error. This is weird because other times, it doesn't give me this error and everything works fine. When trying to connect multiple clients, for some reason, it will only send correctly to one, and then the other client gets the bad file descriptor or "nonsocket" error, even though both threads are processing the same messages and do the same routines. Anyone have an idea why? Here's the code that is giving me that error: while(mqueue.head != mqueue.tail && count < dis_m){ printf("Sending to client %s: %s\n", pointer->id, pointer->message); int fd; fd = open(pointer->message, O_RDONLY); char buf[58368]; int bytesRead; printf("This is fd %d\n", fd); bytesRead=read(fd,buf,58368); send(pointer->socket,buf,bytesRead,0); perror("Error:\n"); fflush(stdout); close(fd); mqueue.mcount--; mqueue.head = mqueue.head->next; free(pointer->message); free(pointer); pointer = mqueue.head; count++; } printf("Sending %s\n", pointer->message); int fd; fd = open(pointer->message, O_RDONLY); printf("This is fd %d\n", fd); printf("I am hhere2\n"); char buf[58368]; int bytesRead; bytesRead=read(fd,buf,58368); send(pointer->socket,buf,bytesRead,0); perror("Error:\n"); close(fd); mqueue.mcount--; if(mqueue.head != mqueue.tail){ mqueue.head = mqueue.head->next; } else{ mqueue.head->next = malloc(sizeof(struct message)); mqueue.head = mqueue.head->next; mqueue.head->next = malloc(sizeof(struct message)); mqueue.tail = mqueue.head->next; mqueue.head->message = NULL; } free(pointer->message); free(pointer); pthread_mutex_unlock(&numm); pthread_mutex_unlock(&circ); pthread_mutex_unlock(&slots); The messages for both threads are the same, being of the form ./path/imageXX.ppm where XX is the number that should go to the client. The file size of each image is 58368 bytes. Sometimes, this code hangs on the read, and stops execution. I don't know this would be either, because the file descriptor comes back as valid. Thanks in advanced. Edit: Here's some sample output: Sending to client a: ./support/images/sw90.ppm This is fd 4 Error: : Socket operation on non-socket Sending to client a: ./support/images/sw91.ppm This is fd 4 Error: : Socket operation on non-socket Sending ./support/images/sw92.ppm This is fd 4 I am hhere2 Error: : Socket operation on non-socket My dispatcher has defeated evil Sample with 2 clients (client b was serviced first) Sending to client b: ./support/images/sw87.ppm This is fd 6 Error: : Success Sending to client b: ./support/images/sw88.ppm This is fd 6 Error: : Success Sending to client b: ./support/images/sw89.ppm This is fd 6 Error: : Success This is fd 6 Error: : Bad file descriptor Sending to client a: ./support/images/sw85.ppm This is fd 6 Error: As you can see, who ever is serviced first in this instance can open the files, but not the 2nd person. Edit2: Full code. Sorry, its pretty long and terribly formatted. #include <netinet/in.h> #include <netinet/in.h> #include <netdb.h> #include <arpa/inet.h> #include <sys/types.h> #include <sys/socket.h> #include <errno.h> #include <stdio.h> #include <unistd.h> #include <pthread.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include "ring.h" /* Version 1 Here is what is implemented so far: The threads are created from the arguments specified (number of threads that is) The server will lock and update variables based on how many clients are in the system and such. The socket that is opened when a new client connects, must be passed to the threads. To do this, we need some sort of global array. I did this by specifying an int client and main_pool_busy, and two pointers poolsockets and nonpoolsockets. My thinking on this was that when a new client enters the system, the server thread increments the variable client. When a thread is finished with this client (after it sends it the data), the thread will decrement client and close the socket. HTTP servers act this way sometimes (they terminate the socket as soon as one transmission is sent). *Note down at bottom After the server portion increments the client counter, we must open up a new socket (denoted by new_sd) and get this value to the appropriate thread. To do this, I created global array poolsockets, which will hold all the socket descriptors for our pooled threads. The server portion gets the new socket descriptor, and places the value in the first spot of the array that has a 0. We only place a value in this array IF: 1. The variable main_pool_busy < worknum (If we have more clients in the system than in our pool, it doesn't mean we should always create a new thread. At the end of this, the server signals on the condition variable clientin that a new client has arrived. In our pooled thread, we then must walk this array and check the array until we hit our first non-zero value. This is the socket we will give to that thread. The thread then changes the array to have a zero here. What if our all threads in our pool our busy? If this is the case, then we will know it because our threads in this pool will increment main_pool_busy by one when they are working on a request and decrement it when they are done. If main_pool_busy >= worknum, then we must dynamically create a new thread. Then, we must realloc the size of our nonpoolsockets array by 1 int. We then add the new socket descriptor to our pool. Here's what we need to figure out: NOTE* Each worker should generate 100 messages which specify the worker thread ID, client socket descriptor and a copy of the client message. Additionally, each message should include a message number, starting from 0 and incrementing for each subsequent message sent to the same client. I don't know how to keep track of how many messages were to the same client. Maybe we shouldn't close the socket descriptor, but rather keep an array of structs for each socket that includes how many messages they have been sent. Then, the server adds the struct, the threads remove it, then the threads add it back once they've serviced one request (unless the count is 100). ------------------------------------------------------------- CHANGES Version 1 ---------- NONE: this is the first version. */ #define MAXSLOTS 30 #define dis_m 15 //problems with dis_m ==1 //Function prototypes void inc_clients(); void init_mutex_stuff(pthread_t*, pthread_t*); void *threadpool(void *); void server(int); void add_to_socket_pool(int); void inc_busy(); void dec_busy(); void *dispatcher(); void create_message(long, int, int, char *, char *); void init_ring(); void add_to_ring(char *, char *, int, int, int); int socket_from_string(char *); void add_to_head(char *); void add_to_tail(char *); struct message * reorder(struct message *, struct message *, int); int get_threadid(char *); void delete_socket_messages(int); struct message * merge(struct message *, struct message *, int); int get_request(char *, char *, char*); ///////////////////// //Global mutexes and condition variables pthread_mutex_t startservice; pthread_mutex_t numclients; pthread_mutex_t pool_sockets; pthread_mutex_t nonpool_sockets; pthread_mutex_t m_pool_busy; pthread_mutex_t slots; pthread_mutex_t numm; pthread_mutex_t circ; pthread_cond_t clientin; pthread_cond_t m; /////////////////////////////////////// //Global variables int clients; int main_pool_busy; int * poolsockets, nonpoolsockets; int worknum; struct ring mqueue; /////////////////////////////////////// int main(int argc, char ** argv){ //error handling if not enough arguments to program if(argc != 3){ printf("Not enough arguments to server: ./server portnum NumThreadsinPool\n"); _exit(-1); } //Convert arguments from strings to integer values int port = atoi(argv[1]); worknum = atoi(argv[2]); //Start server portion server(port); } /////////////////////////////////////////////////////////////////////////////////////////////// //The listen server thread///////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////////// void server(int port){ int sd, new_sd; struct sockaddr_in name, cli_name; int sock_opt_val = 1; int cli_len; pthread_t threads[worknum]; //create our pthread id array pthread_t dis[1]; //create our dispatcher array (necessary to create thread) init_mutex_stuff(threads, dis); //initialize mutexes and stuff //Server setup /////////////////////////////////////////////////////// if ((sd = socket (AF_INET, SOCK_STREAM, 0)) < 0) { perror("(servConn): socket() error"); _exit (-1); } if (setsockopt (sd, SOL_SOCKET, SO_REUSEADDR, (char *) &sock_opt_val, sizeof(sock_opt_val)) < 0) { perror ("(servConn): Failed to set SO_REUSEADDR on INET socket"); _exit (-1); } name.sin_family = AF_INET; name.sin_port = htons (port); name.sin_addr.s_addr = htonl(INADDR_ANY); if (bind (sd, (struct sockaddr *)&name, sizeof(name)) < 0) { perror ("(servConn): bind() error"); _exit (-1); } listen (sd, 5); //End of server Setup ////////////////////////////////////////////////// for (;;) { cli_len = sizeof (cli_name); new_sd = accept (sd, (struct sockaddr *) &cli_name, &cli_len); printf ("Assigning new socket descriptor: %d\n", new_sd); inc_clients(); //New client has come in, increment clients add_to_socket_pool(new_sd); //Add client to the pool of sockets if (new_sd < 0) { perror ("(servConn): accept() error"); _exit (-1); } } pthread_exit(NULL); //Quit } //Adds the new socket to the array designated for pthreads in the pool void add_to_socket_pool(int socket){ pthread_mutex_lock(&m_pool_busy); //Lock so that we can check main_pool_busy int i; //If not all our main pool is busy, then allocate to one of them if(main_pool_busy < worknum){ pthread_mutex_unlock(&m_pool_busy); //unlock busy, we no longer need to hold it pthread_mutex_lock(&pool_sockets); //Lock the socket pool array so that we can edit it without worry for(i = 0; i < worknum; i++){ //Find a poolsocket that is -1; then we should put the real socket there. This value will be changed back to -1 when the thread grabs the sockfd if(poolsockets[i] == -1){ poolsockets[i] = socket; pthread_mutex_unlock(&pool_sockets); //unlock our pool array, we don't need it anymore inc_busy(); //Incrememnt busy (locks the mutex itself) pthread_cond_signal(&clientin); //Signal first thread waiting on a client that a client needs to be serviced break; } } } else{ //Dynamic thread creation goes here pthread_mutex_unlock(&m_pool_busy); } } //Increments the client number. If client number goes over worknum, we must dynamically create new pthreads void inc_clients(){ pthread_mutex_lock(&numclients); clients++; pthread_mutex_unlock(&numclients); } //Increments busy void inc_busy(){ pthread_mutex_lock(&m_pool_busy); main_pool_busy++; pthread_mutex_unlock(&m_pool_busy); } //Initialize all of our mutexes at the beginning and create our pthreads void init_mutex_stuff(pthread_t * threads, pthread_t * dis){ pthread_mutex_init(&startservice, NULL); pthread_mutex_init(&numclients, NULL); pthread_mutex_init(&pool_sockets, NULL); pthread_mutex_init(&nonpool_sockets, NULL); pthread_mutex_init(&m_pool_busy, NULL); pthread_mutex_init(&circ, NULL); pthread_cond_init (&clientin, NULL); main_pool_busy = 0; poolsockets = malloc(sizeof(int)*worknum); int threadreturn; //error checking variables long i = 0; //Loop and create pthreads for(i; i < worknum; i++){ threadreturn = pthread_create(&threads[i], NULL, threadpool, (void *) i); poolsockets[i] = -1; if(threadreturn){ perror("Thread pool created unsuccessfully"); _exit(-1); } } pthread_create(&dis[0], NULL, dispatcher, NULL); } ////////////////////////////////////////////////////////////////////////////////////////// /////////Main pool routines ///////////////////////////////////////////////////////////////////////////////////////// void dec_busy(){ pthread_mutex_lock(&m_pool_busy); main_pool_busy--; pthread_mutex_unlock(&m_pool_busy); } void dec_clients(){ pthread_mutex_lock(&numclients); clients--; pthread_mutex_unlock(&numclients); } //This is what our threadpool pthreads will be running. void *threadpool(void * threadid){ long id = (long) threadid; //Id of this thread int i; int socket; int counter = 0; //Try and gain access to the next client that comes in and wait until server signals that a client as arrived while(1){ pthread_mutex_lock(&startservice); //lock start service (required for cond wait) pthread_cond_wait(&clientin, &startservice); //wait for signal from server that client exists pthread_mutex_unlock(&startservice); //unlock mutex. pthread_mutex_lock(&pool_sockets); //Lock the pool socket so we can get the socket fd unhindered/interrupted for(i = 0; i < worknum; i++){ if(poolsockets[i] != -1){ socket = poolsockets[i]; poolsockets[i] = -1; pthread_mutex_unlock(&pool_sockets); } } printf("Thread #%d is past getting the socket\n", id); int incoming = 1; while(counter < 100 && incoming != 0){ char buffer[512]; bzero(buffer,512); int startcounter = 0; incoming = read(socket, buffer, 512); if(buffer[0] != 0){ //client ID:priority:request:arguments char id[100]; long prior; char request[100]; char arg1[100]; char message[100]; char arg2[100]; char * point; point = strtok(buffer, ":"); strcpy(id, point); point = strtok(NULL, ":"); prior = atoi(point); point = strtok(NULL, ":"); strcpy(request, point); point = strtok(NULL, ":"); strcpy(arg1, point); point = strtok(NULL, ":"); if(point != NULL){ strcpy(arg2, point); } int fd; if(strcmp(request, "start_movie") == 0){ int count = 1; while(count <= 100){ char temp[10]; snprintf(temp, 50, "%d\0", count); strcpy(message, "./support/images/"); strcat(message, arg1); strcat(message, temp); strcat(message, ".ppm"); printf("This is message %s to %s\n", message, id); count++; add_to_ring(message, id, prior, counter, socket); //Adds our created message to the ring counter++; } printf("I'm out of the loop\n"); } else if(strcmp(request, "seek_movie") == 0){ int count = atoi(arg2); while(count <= 100){ char temp[10]; snprintf(temp, 10, "%d\0", count); strcpy(message, "./support/images/"); strcat(message, arg1); strcat(message, temp); strcat(message, ".ppm"); printf("This is message %s\n", message); count++; } } //create_message(id, socket, counter, buffer, message); //Creates our message from the input from the client. Stores it in buffer } else{ delete_socket_messages(socket); break; } } counter = 0; close(socket);//Zero out counter again } dec_clients(); //client serviced, decrement clients dec_busy(); //thread finished, decrement busy } //Creates a message void create_message(long threadid, int socket, int counter, char * buffer, char * message){ snprintf(message, strlen(buffer)+15, "%d:%d:%d:%s", threadid, socket, counter, buffer); } //Gets the socket from the message string (maybe I should just pass in the socket to another method) int socket_from_string(char * message){ char * substr1 = strstr(message, ":"); char * substr2 = substr1; substr2++; int occurance = strcspn(substr2, ":"); char sock[10]; strncpy(sock, substr2, occurance); return atoi(sock); } //Adds message to our ring buffer's head void add_to_head(char * message){ printf("Adding to head of ring\n"); mqueue.head->message = malloc(strlen(message)+1); //Allocate space for message strcpy(mqueue.head->message, message); //copy bytes into allocated space } //Adds our message to our ring buffer's tail void add_to_tail(char * message){ printf("Adding to tail of ring\n"); mqueue.tail->message = malloc(strlen(message)+1); //allocate space for message strcpy(mqueue.tail->message, message); //copy bytes into allocated space mqueue.tail->next = malloc(sizeof(struct message)); //allocate space for the next message struct } //Adds a message to our ring void add_to_ring(char * message, char * id, int prior, int mnum, int socket){ //printf("This is message %s:" , message); pthread_mutex_lock(&circ); //Lock the ring buffer pthread_mutex_lock(&numm); //Lock the message count (will need this to make sure we can't fill the buffer over the max slots) if(mqueue.head->message == NULL){ add_to_head(message); //Adds it to head mqueue.head->socket = socket; //Set message socket mqueue.head->priority = prior; //Set its priority (thread id) mqueue.head->mnum = mnum; //Set its message number (used for sorting) mqueue.head->id = malloc(sizeof(id)); strcpy(mqueue.head->id, id); } else if(mqueue.tail->message == NULL){ //This is the problem for dis_m 1 I'm pretty sure add_to_tail(message); mqueue.tail->socket = socket; mqueue.tail->priority = prior; mqueue.tail->mnum = mnum; mqueue.tail->id = malloc(sizeof(id)); strcpy(mqueue.tail->id, id); } else{ mqueue.tail->next = malloc(sizeof(struct message)); mqueue.tail = mqueue.tail->next; add_to_tail(message); mqueue.tail->socket = socket; mqueue.tail->priority = prior; mqueue.tail->mnum = mnum; mqueue.tail->id = malloc(sizeof(id)); strcpy(mqueue.tail->id, id); } mqueue.mcount++; pthread_mutex_unlock(&circ); if(mqueue.mcount >= dis_m){ pthread_mutex_unlock(&numm); pthread_cond_signal(&m); } else{ pthread_mutex_unlock(&numm); } printf("out of add to ring\n"); fflush(stdout); } ////////////////////////////////// //Dispatcher routines ///////////////////////////////// void *dispatcher(){ init_ring(); while(1){ pthread_mutex_lock(&slots); pthread_cond_wait(&m, &slots); pthread_mutex_lock(&numm); pthread_mutex_lock(&circ); printf("Dispatcher to the rescue!\n"); mqueue.head = reorder(mqueue.head, mqueue.tail, mqueue.mcount); //printf("This is the head %s\n", mqueue.head->message); //printf("This is the tail %s\n", mqueue.head->message); fflush(stdout); struct message * pointer = mqueue.head; int count = 0; while(mqueue.head != mqueue.tail && count < dis_m){ printf("Sending to client %s: %s\n", pointer->id, pointer->message); int fd; fd = open(pointer->message, O_RDONLY); char buf[58368]; int bytesRead; printf("This is fd %d\n", fd); bytesRead=read(fd,buf,58368); send(pointer->socket,buf,bytesRead,0); perror("Error:\n"); fflush(stdout); close(fd); mqueue.mcount--; mqueue.head = mqueue.head->next; free(pointer->message); free(pointer); pointer = mqueue.head; count++; } printf("Sending %s\n", pointer->message); int fd; fd = open(pointer->message, O_RDONLY); printf("This is fd %d\n", fd); printf("I am hhere2\n"); char buf[58368]; int bytesRead; bytesRead=read(fd,buf,58368); send(pointer->socket,buf,bytesRead,0); perror("Error:\n"); close(fd); mqueue.mcount--; if(mqueue.head != mqueue.tail){ mqueue.head = mqueue.head->next; } else{ mqueue.head->next = malloc(sizeof(struct message)); mqueue.head = mqueue.head->next; mqueue.head->next = malloc(sizeof(struct message)); mqueue.tail = mqueue.head->next; mqueue.head->message = NULL; } free(pointer->message); free(pointer); pthread_mutex_unlock(&numm); pthread_mutex_unlock(&circ); pthread_mutex_unlock(&slots); printf("My dispatcher has defeated evil\n"); } } void init_ring(){ mqueue.head = malloc(sizeof(struct message)); mqueue.head->next = malloc(sizeof(struct message)); mqueue.tail = mqueue.head->next; mqueue.mcount = 0; } struct message * reorder(struct message * begin, struct message * end, int num){ //printf("I am reordering for size %d\n", num); fflush(stdout); int i; if(num == 1){ //printf("Begin: %s\n", begin->message); begin->next = NULL; return begin; } else{ struct message * left = begin; struct message * right; int middle = num/2; for(i = 1; i < middle; i++){ left = left->next; } right = left -> next; left -> next = NULL; //printf("Begin: %s\nLeft: %s\nright: %s\nend:%s\n", begin->message, left->message, right->message, end->message); left = reorder(begin, left, middle); if(num%2 != 0){ right = reorder(right, end, middle+1); } else{ right = reorder(right, end, middle); } return merge(left, right, num); } } struct message * merge(struct message * left, struct message * right, int num){ //printf("I am merginging! left: %s %d, right: %s %dnum: %d\n", left->message,left->priority, right->message, right->priority, num); struct message * start, * point; int lenL= 0; int lenR = 0; int flagL = 0; int flagR = 0; int count = 0; int middle1 = num/2; int middle2; if(num%2 != 0){ middle2 = middle1+1; } else{ middle2 = middle1; } while(lenL < middle1 && lenR < middle2){ count++; //printf("In here for count %d\n", count); if(lenL == 0 && lenR == 0){ if(left->priority < right->priority){ start = left; //Set the start point point = left; //set our enum; left = left->next; //move the left pointer point->next = NULL; //Set the next node to NULL lenL++; } else if(left->priority > right->priority){ start = right; point = right; right = right->next; point->next = NULL; lenR++; } else{ if(left->mnum < right->mnum){ ////printf("This is where we are\n"); start = left; //Set the start point point = left; //set our enum; left = left->next; //move the left pointer point->next = NULL; //Set the next node to NULL lenL++; } else{ start = right; point = right; right = right->next; point->next = NULL; lenR++; } } } else{ if(left->priority < right->priority){ point->next = left; left = left->next; //move the left pointer point = point->next; point->next = NULL; //Set the next node to NULL lenL++; } else if(left->priority > right->priority){ point->next = right; right = right->next; point = point->next; point->next = NULL; lenR++; } else{ if(left->mnum < right->mnum){ point->next = left; //set our enum; left = left->next; point = point->next;//move the left pointer point->next = NULL; //Set the next node to NULL lenL++; } else{ point->next = right; right = right->next; point = point->next; point->next = NULL; lenR++; } } } if(lenL == middle1){ flagL = 1; break; } if(lenR == middle2){ flagR = 1; break; } } if(flagL == 1){ point->next = right; point = point->next; for(lenR; lenR< middle2-1; lenR++){ point = point->next; } point->next = NULL; mqueue.tail = point; } else{ point->next = left; point = point->next; for(lenL; lenL< middle1-1; lenL++){ point = point->next; } point->next = NULL; mqueue.tail = point; } //printf("This is the start %s\n", start->message); //printf("This is mqueue.tail %s\n", mqueue.tail->message); return start; } void delete_socket_messages(int a){ }

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