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• Custom Database integration with MOSS 2007

  - by Bob

  Hopefully someone has been down this road before and can offer some sound advice as far as which direction I should take. I am currently involved in a project in which we will be utilizing a custom database to store data extracted from excel files based on pre-established templates (to maintain consistency). We currently have a process (written in C#.Net 2008) that can extract the necessary data from the spreadsheets and import it into our custom database. What I am primarily interested in is figuring out the best method for integrating that process with our portal. What I would like to do is let SharePoint keep track of the metadata about the spreadsheet itself and let the custom database keep track of the data contained within the spreadsheet. So, one thing I need is a way to link spreadsheets from SharePoint to the custom database and vice versa. As these spreadsheets will be updated periodically, I need tried and true way of ensuring that the data remains synchronized between SharePoint and the custom database. I am also interested in finding out how to use the data from the custom database to create reports within the SharePoint portal. Any and all information will be greatly appreciated.

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• when long polling, Why are my other requests taking so long?

  - by Pascal

  The client makes 2 concurrent requests. (1 which takes 60 seconds - long polling) and another which is NOT long polling - supposed to return right away. It does return right away when I'm not doing long polling. But as soon as I start doing long polling with the other thread, the other one takes forever to execute. Firebug shows that the request is waiting for 10-50 seconds. On the server, I profiled ALL requests from the moment the php script starts to the time it goes back to the client, and it shows that each one only took 300ms or less. This problem started about the same time I started doing long polling (with the other XHR requests). I'm using jquery for both requests. The server shows that it is under very light load. CPU and memory less then 2%. 8 processes running out of a pool of 15. (it doesn't seem to deviate much from that number 8, even when I run more ajax requests). I guess each process can run multiple ajax threads concurrently. I made sure to EXIT from all processes as soon as their done executing. I don't see how the process pool has run out, if there are still 7 unused processes listed under prstat -J. Also, the problem happens somewhat intermittently. Firefox should be able to handle 2 concurrent ajax requests. i dont get what the problem is.

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• What is the relationship between Turing Machine & Modern Computer ? [closed]

  - by smwikipedia

  I heard a lot that modern computers are based on Turing machine. I just cannot build a bridge between a conceptual Turing Machine and a modern computer. Could someone help me build this bridge? Below is my current understanding. I think the computer is a big general-purpose Turing machine. Each program we write is a small specific-purpose Turing machine. The classical Turing machine do its job based on the input and its current state inside and so do our programs. Let's take a running program (a process) as an example. We know that in the process's address space, there's areas for stack, heap, and code. A classical Turing machine doesn't have the ability to remember many things, so we borrow the concept of stack from the push-down automaton. The heap and stack areas contains the state of our specific-purpose Turing machine (our program). The code area represents the logic of this small Turing machine. And various I/O devices supply input to this Turing machine.

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• Can I use RegFree Com with an application written in Excel VBA?

  - by Steven

  I have an application that is written in Excel VBA, myApp.xls. Currently we use InstallShield to distribute the application. Since we are moving to Windows Vista, I need to be able to install the application as a standard user. This does not allow for me to update the registry during the install process. In addition to the excel application we also have several VB6 applications. In order to install those applications, I was able to use RegFree com and Make My Manifest (MMM) as suggested by people on this forum (I greatly appreciate the insight btw!). This process, although a bit tedious, worked well. I then packaged the output from MMM in a VS '05 installer project and removed the UAC prompt on the msi using msiinfo.exe. Now I am faced with installing an application that basically lives in an Excel file. I modified a manifest that MMM created for me for one of my VB6 apps and tried to run the excel file through that, but I did not have much luck. Does anybody know of a way to do this? Does RegFree com work with VBA? Any thoughts or suggestions would be much appreciated. Thanks, Steve

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• Lua Alien Module - Trouble using WriteProcessMemory function, unsure on types (unit32)

  - by jefferysanders

  require "alien" --the address im trying to edit in the Mahjong game on Win7 local SCOREREF = 0x0744D554 --this should give me full access to the process local ACCESS = 0x001F0FFF --this is my process ID for my open window of Mahjong local PID = 1136 --function to open proc local op = alien.Kernel32.OpenProcess op:types{ ret = "pointer", abi = "stdcall"; "int", "int", "int"} --function to write to proc mem local wm = alien.Kernel32.WriteProcessMemory wm:types{ ret = "long", abi = "stdcall"; "pointer", "pointer", "pointer", "long", "pointer" } local pRef = op(ACCESS, true, PID) local buf = alien.buffer("99") -- ptr,uint32,byte arr (no idea what to make this),int, ptr print( wm( pRef, SCOREREF, buf, 4, nil)) --prints 1 if success, 0 if failed So that is my code. I am not even sure if I have the types set correctly. I am completely lost and need some guidance. I really wish there was more online help/documentation for alien, it confuses my poor brain. What utterly baffles me is that it WriteProcessMemory will sometimes complete successfully (though it does nothing at all, to my knowledge) and will also sometimes fail to complete successfully. As I've stated, my brain hurts. Any help appreciated.

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• Business Layer Pattern on Rails? MVCL

  - by Fabiano PS

  That is a broad question, and I appreciate no short/dumb asnwers like: "Oh that is the model job, this quest is retarded (period)" PROBLEM Where I work at people created a system over 2 years for managing the manufacture process over demand in the most simplified still broad as possible, involving selling, buying, assemble, The system is coded over Ruby On Rails. The result has been changed lots of times and the result is a mess on callbacks (some are called several times), 200+ models, and fat controllers: Total bad. The QUESTION is, if there is a gem, or pattern designed to handle Rails large app logic? The logic whould be able to fully talk to models (whose only concern would be data format handling and validation) What I EXPECT is to reduce complexity from various controllers, and hard to track callbacks into files with the responsibility to handle a business operation logic. In some cases there is the need to wait for a response, in others, only validation of the input is enough and a bg process would take place. ie: -- Sell some products (need to wait the operation to finish) 1. Set a View able to get the products input 2. Controller gets the product list inputed by employee and call the logic Logic::ExecuteWithResponse('sell', 'products', :prods => @product_list_with_qtt, :when => @date, :employee => current_user() ) This Logic would handle buying order, assemble order, machine schedule, warehouse reservation, and others

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• Identifying and Resolving Oracle ITL Deadlock

  - by Allan

  I have an Oracle DB package that is routinely causing what I believe is an ITL (Interested Transaction List) deadlock. The relevant portion of a trace file is below. Deadlock graph: ---------Blocker(s)-------- ---------Waiter(s)--------- Resource Name process session holds waits process session holds waits TM-0000cb52-00000000 22 131 S 23 143 SS TM-0000ceec-00000000 23 143 SX 32 138 SX SSX TM-0000cb52-00000000 30 138 SX 22 131 S session 131: DID 0001-0016-00000D1C session 143: DID 0001-0017-000055D5 session 143: DID 0001-0017-000055D5 session 138: DID 0001-001E-000067A0 session 138: DID 0001-001E-000067A0 session 131: DID 0001-0016-00000D1C Rows waited on: Session 143: no row Session 138: no row Session 131: no row There are no bit-map indexes on this table, so that's not the cause. As far as I can tell, the lack of "Rows waited on" plus the "S" in the Waiter waits column likely indicates that this is an ITL deadlock. Also, the table is written to quite often (roughly 8 insert or updates concurrently, as often as 240 times a minute), so and ITL deadlock seems like a strong possibility. I've increased the INITRANS parameter of the table and it's indexes to 100 and increased the PCT_FREE on the table from 10 to 20 (then rebuilt the indexes), but the deadlocks are still occurring. The deadlock seems to happen most often during an update, but that could just be a coincidence, as I've only traced it a couple of times. My questions are two-fold: 1) Is this actually an ITL deadlock? 2) If it is an ITL deadlock, what else can be done to avoid it?

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• Memory mapped files and "soft" page faults. Unavoidable?

  - by Robert Oschler

  I have two applications (processes) running under Windows XP that share data via a memory mapped file. Despite all my efforts to eliminate per iteration memory allocations, I still get about 10 soft page faults per data transfer. I've tried every flag there is in CreateFileMapping() and CreateFileView() and it still happens. I'm beginning to wonder if it's just the way memory mapped files work. If anyone there knows the O/S implementation details behind memory mapped files I would appreciate comments on the following theory: If two processes share a memory mapped file and one process writes to it while another reads it, then the O/S marks the pages written to as invalid. When the other process goes to read the memory areas that now belong to invalidated pages, this causes a soft page fault (by design) and the O/S knows to reload the invalidated page. Also, the number of soft page faults is therefore directly proportional to the size of the data write. My experiments seem to bear out the above theory. When I share data I write one contiguous block of data. In other words, the entire shared memory area is overwritten each time. If I make the block bigger the number of soft page faults goes up correspondingly. So, if my theory is true, there is nothing I can do to eliminate the soft page faults short of not using memory mapped files because that is how they work (using soft page faults to maintain page consistency). What is ironic is that I chose to use a memory mapped file instead of a TCP socket connection because I thought it would be more efficient. Note, if the soft page faults are harmless please note that. I've heard that at some point if the number is excessive, the system's performance can be marred. If soft page faults intrinsically are not significantly harmful then if anyone has any guidelines as to what number per second is "excessive" I'd like to hear that. Thanks.

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• segmentation fault on Unix - possible stack corruption

  - by bob

  hello, i'm looking at a core from a process running in Unix. Usually I can work my around and root into the backtrace to try identify a memory issue. In this case, I'm not sure how to proceed. Firstly the backtrace only gives 3 frames where I would expect alot more. For those frames, all the function parameters presented appears to completely invalid. There are not what I would expect. Some pointer parameters have the following associated with them - Cannot access memory at address Would this suggest some kind of complete stack corruption. I ran the process with libumem and all the buffers were reported as being clean. umem_status reported nothing either. so basically I'm stumped. What is the likely causes? What should I look for in code since libumem appears to have reported no errors. Any suggestions on how I can debug furhter? any extra features in mdb I should consider? thank you.

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• Forking in PHP on Windows

  - by Doug Kavendek

  We are running PHP on a Windows server (a source of many problems indeed, but migrating is not an option currently). There are a few points where a user-initiated action will need to kick off a few things that take a while and about which the user doesn't need to know if they succeed or fail, such as sending off an email or making sure some third-party accounts are updated. If I could just fork with pcntl_fork(), this would be very simple, but the PCNTL functions are not available in Windows. It seems the closest I can get is to do something of this nature: exec( 'php-cgi.exe somescript.php' ); However, this would be far more complicated. The actions I need to kick off rely on a lot of context that already will exist in the running process; to use the above example, I'd need to figure out the essential data and supply it to the new script in some way. If I could fork, it'd just be a matter of letting the parent process return early, leaving the child to work on a few more things. I've found a few people talking about their own work in getting various PCNTL functions compiled on Windows, but none seemed to have anything available (broken links, etc). Despite this question having practically the same name as mine, it seems the problem was more execution timeout than needing to fork. So, is my best option to just refactor a bit to deal with calling php-cgi, or are there other options? Edit: It seems exec() won't work for this, at least not without me figuring some other aspect of it, as it waits until the call returns. I figured I could use START, sort of like exec( 'start php-cgi.exe somescript.php' );, but it still waits until the other script finishes.

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• How can I turn a column name into a result value in SQL Server?

  - by Brennan

  I have a table which has essentially boolean values in a legacy database. The column names are stored as string values in another table so I need to match the column names of one table to a string value in another table. I know there has to be a way to do this directly with SQL in SQL Server but it is beyond me. My initial thought was to use PIVOT but it is not enabled by default and enabling it would likely be a difficult process with pushing that change to the Production database. I would prefer to use what is enabled by default. I am considering using COALESCE to translate the boolean value to the string that value that I need. This will be a manual process. I think I will also use a table variable to insert the results of the first query into that variable and use those results to do the second query. I still have the problem that the columns are on a single row so I wish I could easily pivot the values to put the column names in the result set as strings. But if I could easily do that I could easily write the query with a sub-select. Any tips are welcome.

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• wcf 4.0 service on IIS7

  - by Jan

  I am currently developing a service with wcf 4.0 (visual studio 2010 RC). When I try my service on the Visual Studio Development Server, it all works perfect. However, when I tree to run my service on IIS7 on a windows 7 machine, the service doesn't work anymore. (I already changed the framework version on my application pool). When I call an operation on the service, like the default operation GetData when I create a service, I get an error. I used the WCF test client to connect to the service. When I call the operation on the service, the Visual Studio Just-In-Time debugger shows the following message: An unhandled win32 exception occured in w3wp.exe The Just-In-Time debugger was launched without necessary security permissions. To debug this proces, the JIT debugger must be run as an administrator. Would you like to debug the proces? As far as I know, I am running Visual Studio as an administrator and this is probably the process that starts the JIT debugger. The only option I have is to debug the W3WP process, which is probably not the right thing to do. What can I do the make the Service to run on IIS7?

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• SQL (mySQL) update some value in all records processed by a select

  - by jdmuys

  I am using mySQL from their C API, but that shouldn't be relevant. My code must process records from a table that match some criteria, and then update the said records to flag them as processed. The lines in the table are modified/inserted/deleted by another process I don't control. I am afraid in the following, the UPDATE might flag some records erroneously since the set of records matching might have changed between step 1 and step 3. SELECT * FROM myTable WHERE <CONDITION>; # step 1 <iterate over the selected set of lines. This may take some time.> # step 2 UPDATE myTable SET processed=1 WHERE <CONDITION> # step 3 What's the smart way to ensure that the UPDATE updates all the lines processed, and only them? A transaction doesn't seem to fit the bill as it doesn't provide isolation of that sort: a recently modified record not in the originally selected set might still be targeted by the UPDATE statement. For the same reason, SELECT ... FOR UPDATE doesn't seem to help, though it sounds promising :-) The only way I can see is to use a temporary table to memorize the set of rows to be processed, doing something like: CREATE TEMPORARY TABLE workOrder (jobId INT(11)); INSERT INTO workOrder SELECT myID as jobId FROM myTable WHERE <CONDITION>; SELECT * FROM myTable WHERE myID IN (SELECT * FROM workOrder); <iterate over the selected set of lines. This may take some time.> UPDATE myTable SET processed=1 WHERE myID IN (SELECT * FROM workOrder); DROP TABLE workOrder; But this seems wasteful and not very efficient. Is there anything smarter? Many thanks from a SQL newbie.

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• Wizard form in Struts

  - by Kuntal Basu

  I am creating a wizard in Struts. It cotains 4 steps. For Each step I have separate ActionClass say:- Step1Action.java Step2Action.java Step3Action.java Step4Action.java and in each class there are 2 methods input() and process(). input() method is for showing the page in input mode process() method is will be use for processing the submitted data (if validation is ok) I am carrying all data upto the last step in a session. And saving all of them in database in the last step Similaly 4 action tags in struts.xml like :- <action name="step1" class="com.mycomp.myapp.action.Step1Action1" method="input"> <result name="success" type="redirectAction">step2</result> <result name="input">/view/step1.jsp</result> </action> <action name="step2" class="com.mycomp.myapp.action.Step1Action2" method="input"> <result name="success" type="redirectAction">step3</result> <result name="input">/view/step2.jsp</result> </action> But I think I am going wrong. Please Tell me How will I handle This case?

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• Database INSERT does not take place

  - by reggie

  My code is as follows: <?php include("config.php"); $ip=$_SERVER['REMOTE_ADDR']; if($_POST['id']) { $id=$_POST['id']; $id = mysql_escape_String($id); $ip_sql=mysql_query("select ip_add from Voting_IP where mes_id_fk='$id' and ip_add='$ip'"); $count=mysql_num_rows($ip_sql); if($count==0) { $sql = "update Messages set up=up+1 where mes_id='$id'"; mysql_query($sql); $sql_in = "insert into Voting_IP (mes_id_fk,ip_add) values ('$id','$ip')"; mysql_query($sql_in) or die(mysql_error()); echo "<script>alert('Thanks for the vote');</script>"; } else { echo "<script>alert('You have already voted');</script>"; } $result=mysql_query("select up from Messages where mes_id='$id'"); $row=mysql_fetch_array($result); $up_value=$row['up']; echo "<img src='button.png' width='110' height='90'>"; echo $up_value; } ?> My problem is that the insert process does not take place at all. The script tags echos an alert box. Even the img tag is echoed to the web page. But the insert process does not take place. The config file is fine. Note: This code works on my local machine which has PHP 5.3 but it does not work on the server which has PHP 5.2. Any advice?

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• PLKs and Web Service Software Factory

  - by Nix

  We found a bug in Web Service Software Factory a description can be found here. There has been no updates on it so we decided to download the code and fix it ourself. Very simple bug and we patched it with maybe 3 lines of code. However* we have now tried to repackage it and use it and are finding that this is seemingly an impossible process. Can someone please explain to me the process of PLKs? I have read all about them but still don't understand what is really required to distribute a VS package. I was able to get it to load and run using a PLK obtained from here, but i am assuming that you have to be a partner to get a functional PLK that will be recognized on other peoples systems? Every time i try and install this on a different computer I get a "Package Load Failure". Is the reason I am getting errors because I am not using a partner key? Is there any other way around this? For instance is there any way we can have an "internal" VS package that we can distribute? Edit Files I had to change to get it to work. First run devenv PostInstall.proj Generate your plks and replace ##Package PLK## (.resx files) --Just note that package version is not the class name but is "Web Service Software Factory: Modeling Edition" -- And you need to remove the new lines from the key ProductDefinitionRegistryFragment.wxi line 1252(update version to whatever version you used in plk) Uncomment all // [VSShell::ProvideLoadKey("Standard", Constant in .tt files.

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• Creating nodes porgramatically in Drupal 6

  - by John

  Hey, I have been searching for how to create nodes in Drupal 6. I found some entries here on stackoverflow, but the questions seemed to either be for older versions or the solutions did not work for me. Ok, so here is my current process for trying to create $node = new stdClass(); $node->title = "test title"; $node->body = "test body"; $node->type= "story"; $node->created = time(); $node->changed = $node->created; $node->status = 1; $node->promote = 1; $node->sticky = 0; $node->format = 1; $node->uid = 1; node_save( $node ); When I execute this code, the node is created, but when I got the administration page, it throws the following errors: warning: Invalid argument supplied for foreach() in C:\wamp\www\steelylib\includes\menu.inc on line 258. warning: Invalid argument supplied for foreach() in C:\wamp\www\steelylib\includes\menu.inc on line 258. user warning: Duplicate entry '36' for key 1 query: INSERT INTO node_comment_statistics (nid, last_comment_timestamp, last_comment_name, last_comment_uid, comment_count) VALUES (36, 1269980590, NULL, 1, 0) in C:\wamp\www\steelylib\sites\all\modules\nodecomment\nodecomment.module on line 409. warning: Invalid argument supplied for foreach() in C:\wamp\www\steelylib\includes\menu.inc on line 258. warning: Invalid argument supplied for foreach() in C:\wamp\www\steelylib\includes\menu.inc on line 258. I've looked at different tutorials, and all seem to follow the same process. I'm not sure what I am doing wrong. I am using Drupal 6.15. When I roll back the database (to right before I made the changes) the errors are gone. Any help is appreciated!

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• Fork or copy a users browser session in IE

  - by jmoeller

  Is it possible to fork a users session (or do something similar) in a Internet Explorer plugin? I want to process the page the user is on when they click a button in the toolbar. To avoid interrupting the users browsing, I'd like to "copy" everything so I can parse and process the page in the background. The processing can involve things such as loading the content of the result links on a Google search, if that's where the button was clicked. So - what I basically want is to imitate "Ctrl+N" but hide the window from the user, so they won't be interrupted. As you can see, if you fill out and submit the form on http://www.snee.com/xml/crud/posttest.html and press "Ctrl+N", everything posted will still appear in the new window, but it won't post the data twice. I was thinking of somehow copying the IWebBrowser2, but: I'm not sure if that's possible (I haven't been able to find any information on MSDN) I don't know if it copies the sessions as well. Creating a new instance of the IWebBrowser2 and simply navigating to the current URL isn't a valid solution as POST-variables of course doesn't get carried over.

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• Is it possible to use OAuth starting from the service provider website?

  - by Brian Armstrong

  I want to let people create apps that use my API and authenticate them with OAuth. Normally this process starts from the consumer service website (say TwitPic) and they request an access token from the service provider (Twitter). The user is then taken to the service provider website where they have to allow/deny access to to the consumer. I'm wondering if it's possible to initiate this process from the service provider website instead. So in this example you would start on Twitter's site, and maybe there is a section marked "do you want to turn on access for TwitPic?". If you click yes, it passes the access token directly to TwitPic which now has access to your account. Basically, fewer steps. I'm looking at the OAuth docs and it looks like the request token is generated on the consumer side and used later to turn it into an access token. So it's not really designed with what I described above in mind, but I thought there might be a way. http://oauth.net/core/1.0/ (Search for "steps") Thanks!

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• WF performance with new 20,000 persisted workflow instances each month

  - by Nikola Stjelja

  Windows Workflow Foundation has a problem that is slow when doing WF instances persistace. I'm planning to do a project whose bussiness layer will be based on WF exposed WCF services. The project will have 20,000 new workflow instances created each month, each instance could take up to 2 months to finish. What I was lead to belive that given WF slownes when doing peristance my given problem would be unattainable given performance reasons. I have the following questions: Is this true? Will my performance be crap with that load(given WF persitance speed limitations) How can I solve the problem? We currently have two possible solutions: 1. Each new buisiness process request(e.g. Give me a new drivers license) will be a new WF instance, and the number of persistance operations will be limited by forwarding all status request operations to saved state values in a separate database. 2. Have only a small amount of Workflow Instances up at any give time, without any persistance ofso ever(only in case of system crashes etc.), by breaking each workflow stap in to a separate worklof and that workflow handling each business process request instance in the system that is at that current step(e.g. I'm submitting my driver license reques form, which is step one... we have 100 cases of that, and my step one workflow will handle every case simultaneusly). I'm very insterested in solution for that problem. If you want to discuss that problem pleas be free to mail me at [email protected]

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• Application doesn't exit with 0 threads

  - by Bryce Wagner

  We have a WinForms desktop application, which is heavily multithreaded. 3 threads run with Application.Run and a bunch of other background worker threads. Getting all the threads to shut down properly was kind of tricky, but I thought I finally got it right. But when we actually deployed the application, users started experiencing the application not exiting. There's a System.Threading.Mutex to prevent them from running the app multiple times, so they have to go into task manager and kill the old one before they can run it again. Every thread gets a Thread.Join before the main thread exits, and I added logging to each thread I spawn. According to the log, every single thread that starts also exits, and the main thread also exits. Even stranger, running SysInternals ProcessExplorer show all the threads disappear when the application exits. As in, there are 0 threads (managed or unmanaged), but the process is still running. I can't reproduce this on any developers computers or our test environment, and so far I've only seen it happen on Windows XP (not Vista or Windows 7 or any Windows Server). How can a process keep running with 0 threads?

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• Locking issues with replacing files on a website

  - by Moe Sisko

  I want to replace existing files on an IIS website with updated versions. Say these files are large pdf documents, which can be accessed via hyperlinks. The site is up 24x7, so I'm concerned about locking issues when a file is being updated at exactly the same time that someone is trying to read the file. The files are updated using C# code run on the server. I can think of two options for opening the file for writing. Option 1) Open the file for writing, using FileShare.Read : using (FileStream stream = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.Read)) While this file is open, and a user requests the same file for reading in a web browser via a hyperlink, the document opens up as a blank page. Option 2) Open the file for writing using FileShare.None : using (FileStream stream = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.None)) While this file is open, and a user requests the same file for reading in a web browser via a hyperlink, the browser shows an error. In IE 8, you get HTTP 500, "The website cannot display the page", and in Firefox 3.5, you get : "The process cannot access the file because it is being used by another process." The browser behaviour kind of makes sense, and seem reasonable. I guess its highly unlikely that a user will attempt to read a file at exactly the same time you are updating it. It would be nice if somehow, the file update was atomic, like updating a database with SQL wrapped around a transaction. I'm wondering if you guys worry about this sort of thing, and prefer either of the above options, or even have other options of your own for updating files.

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• Which technology is best suited to store and query a huge readonly graph?

  - by asmaier

  I have a huge directed graph: It consists of 1.6 million nodes and 30 million edges. I want the users to be able to find all the shortest connections (including incoming and outgoing edges) between two nodes of the graph (via a web interface). At the moment I have stored the graph in a PostgreSQL database. But that solution is not very efficient and elegant, I basically need to store all the edges of the graph twice (see my question PostgreSQL: How to optimize my database for storing and querying a huge graph). It was suggested to me to use a GraphDB like neo4j or AllegroGraph. However the free version of AllegroGraph is limited to 50 million nodes and also has a very high-level API (RDF), which seems too powerful and complex for my problem. Neo4j on the other hand has only a very low level API (and the python interface is not mature yet). Both of them seem to be more suited for problems, where nodes and edges are frequently added or removed to a graph. For a simple search on a graph, these GraphDBs seem to be too complex. One idea I had would be to "misuse" a search engine like Lucene for the job, since I'm basically only searching connections in a graph. Another idea would be, to have a server process, storing the whole graph (500MB to 1GB) in memory. The clients could then query the server process and could transverse the graph very quickly, since the graph is stored in memory. Is there an easy possibility to write such a server (preferably in Python) using some existing framework? Which technology would you use to store and query such a huge readonly graph?

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• How to use SQLAlchemy to dump an SQL file from query expressions to bulk-insert into a DBMS?

  - by Mahmoud Abdelkader

  Please bear with me as I explain the problem, how I tried to solve it, and my question on how to improve it is at the end. I have a 100,000 line csv file from an offline batch job and I needed to insert it into the database as its proper models. Ordinarily, if this is a fairly straight-forward load, this can be trivially loaded by just munging the CSV file to fit a schema, but I had to do some external processing that requires querying and it's just much more convenient to use SQLAlchemy to generate the data I want. The data I want here is 3 models that represent 3 pre-exiting tables in the database and each subsequent model depends on the previous model. For example: Model C --> Foreign Key --> Model B --> Foreign Key --> Model A So, the models must be inserted in the order A, B, and C. I came up with a producer/consumer approach: - instantiate a multiprocessing.Process which contains a threadpool of 50 persister threads that have a threadlocal connection to a database - read a line from the file using the csv DictReader - enqueue the dictionary to the process, where each thread creates the appropriate models by querying the right values and each thread persists the models in the appropriate order This was faster than a non-threaded read/persist but it is way slower than bulk-loading a file into the database. The job finished persisting after about 45 minutes. For fun, I decided to write it in SQL statements, it took 5 minutes. Writing the SQL statements took me a couple of hours, though. So my question is, could I have used a faster method to insert rows using SQLAlchemy? As I understand it, SQLAlchemy is not designed for bulk insert operations, so this is less than ideal. This follows to my question, is there a way to generate the SQL statements using SQLAlchemy, throw them in a file, and then just use a bulk-load into the database? I know about str(model_object) but it does not show the interpolated values. I would appreciate any guidance for how to do this faster. Thanks!

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• Silverlight 4 seems like starving of memory

  - by Marco

  I have been playing a bit with Silverlight and try to port my Silverlight 3.0 application to Silverlight 4.0. My application loads different XAP files and upon a user request create an instance of a Xaml user control and adds it to the main container, in a sort of MEF approach in order I can have an extensible and pluggable application. The application is pretty huge and to keep acceptable the performances and the initial loading I have built up some helper classes to load in the background all pages and user controls that might be used later on. On Silverlight 3.0 everything was running smoothly without any problem so far. Switching to SL 4.0 I have noticed that when the process approaches to create the instances of the user controls the layout freezes unexpectedly for a minute and sometimes for more. Looking at the task manager the memory usage of IE jumps from 50MB to 400MB and sometimes up to 1.5 GB. If the process won't take that much the layout is rendered properly even though the memory usage is still extremely high. Otherwise everything crashes due to out of memory exception. Running the same application compiled in SL3, the memory used is about 200MB when all the usercontrols are loaded. Time spent to load the application in SL3 is about 10 seconds, while it takes up to 3 mins in SL4 There are no transparencies, no opacities set, no effects and animations in the layout. User controls are instantied on the fly and added or removed in the visual tree on purpose when the user switches from one screen to another. The resources are all cleaned properly when a usercontrol is removed from the visual tree to allow the GC to operate in the background. I may do something wrong but I could not figure out where exactly nail out the source of this problem. As far as I know there is no memory profiler in SL4 that can help me out to find where to look at. But again I could not be updated on new debugging tools available.

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