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  • where is my disk space?

    - by user166241
    I recently had a problem with .xsession-errors file - it became very big ( 90GB) and took all disk space: How I can check what takes disk space in /tmp?. I cleaned it with command > .xsession-errors but after an hour it became large again. So I deleted it (rm .xsession-errors) - it helped because it wasn't recreated but again after hour disk space disappeared - now there is no .xsession-errors anymore but I don't know where is the memory: df Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 106640456 101223392 4 100% / udev 8166744 8 8166736 1% /dev tmpfs 3270224 972 3269252 1% /run none 5120 0 5120 0% /run/lock none 8175552 152 8175400 1% /run/shm du -sc * .[^.]* | sort -n 0 initrd.img 0 initrd.img.old 0 proc 0 sys 0 vmlinuz 0 vmlinuz.old 4 cdrom 4 lib64 4 media 4 mnt 4 selinux 8 dev 12 srv 16 lost+found 68 tmp 1124 run 3396 lib32 5164 .rpmdb 5540 root 8888 sbin 9120 bin 17132 etc 106080 opt 116956 boot 861908 lib 3530584 usr 3821836 var 13371260 home 21859112 total So there is around 100GB used but executing du -sc * .[^.]* | sort -n in root directory finds only ~21 GB - so what takes 80GB?? How to check it? I suspect that when I deleted the `.xsession-errors' file the errors were redirected somwhere else - but where?

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  • Multiboot USB (OSX only): How to customize partition name?

    - by wrk2bike
    Trying to deal with all the Mac OSX recovery disks I've got by moving them to bootable USB images. I've got a big USB drive with multiple partitions for each recovery disk, and it's easy to use Disk Utility to "restore" the recovery DVD to a partition. When I boot my target Mac while holding down the Alt key, I can see all my bootable images and they work great. Problem is, they've all got the same name: "Mac OS X Install DVD." I manage Macs of various vintages. If my target Mac needs 10.6.3 for example, my only option seems to be to try each one until I get past the "Mac OSX can't be installed on this computer" message. I originally named my partitions with the OSX revision number, but that name is replaced by the disk image name during Disk Utility restore. Is there any way to customize the name during or after Disk Utility restore? I tried making a new DVD image on disk first and renaming it, but when I restore it to my recovery partition it has the original name. EDIT: After booting to the wrong partition, and getting the "..can't be installed" message, I can open the Startup Disk menu and see the other partitions - and as I select each one, the info at the bottom indicates which OS revision is on that partition. So I know the info is in there! Just want it at the boot screen if possible.

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  • Non-volatile cache RAID controllers: what kind of protection is there against NVCACHE failure?

    - by astrostl
    The battery back-up (BBU) model: admin enables write-back cache with BBU writes are cached to the RAID controller's RAM (major performance benefit) the battery saves uncommitted and cached data in the event of a power loss (reliability) If I lose power and come back within a day or so, my data should be both complete and uncorrupted. The downside to this is that, if the battery is dead or low, OR EVEN IF IT IS IN A RELEARN CYCLE (drain/charge loops to ensure the battery's health), the controller reverts to write-through mode and performance will suffer. What's more, the relearn cycles are usually automated on a schedule which may or may not happen in the middle of big traffic. So, that has to be manually disabled and manually scheduled for off-hours if it's a concern. Annoying either way. NV caches have capacitors with a sufficient charge to commit any uncommitted-to-disk data to flash. Not only is that more survivable in longer loss situations, but you don't have to concern yourself with battery death, wear-out, or relearning. All of that sounds great to me. What doesn't sound great to me is the prospect of that flash module having an issue, though. What if it's completely hosed? What if it's only partially hosed? A bit corrupted at the edges? Relearn cycles can tell when something like a simple battery is failing, but is there a similar process to verify that the flash is functional? I'm just far more trusting of a battery, warts and all. I know the card's RAM can fail, the card itself can fail - that's common territory, though. In case you didn't guess, yeah, I've experienced a shocking-to-me amount of flash/SSD/etc. failure :)

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  • How can I undo what I did when I accidentally booted linux host inside itself with VMware?

    - by ThomasGHenry
    Hello, I'm dual booting XP and Kubuntu. I wanted to boot to my existing raw scsi XP partition inside Kubuntu, not a virtual XP instance. I accidentally booted Kubuntu inside itself. I know this is a big mistake, so I interrupted the VM, which saved the state and closed. I rebooted the host and now I can't load the Kubuntu partition at boot time. I get a maintenance shell and the Kubuntu partition is read-only. I am able to boot XP as usual. I removed the HDD and tried to mount it on another computer as an external drive and neither partition (XP or Kubuntu) will be recognized, it just appears to be one device that still mounts and appears empty. From the maintenance shell I can see all the files are still on the Kubuntu partition. How can I undo what I did when I accidentally booted Kubuntu inside itself? Is it a matter of unlocking some files somewhere? how can I do that on a RO filesystem? Thanks!

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  • Server down at 23:26 every night

    - by miccet
    We are having a big problem with our sites stability the last couple of weeks and after endless hours of troubleshooting I don't get anywhere. So I turn to you dear community. Setup: 2 x VPS servers - Front end, 8 core, 8G RAM. - Database, 5 core, 3G RAM. Both running Ubuntu. Ruby on Rails EE with Passenger 3 and Rails 2.3.11. MySQL 5.1.67. The problem is that each night, at the exact same time (23:26) the SQL server suddenly shows a processlist full of COMMIT with an increasing Time. After 30-40 seconds (can go longer) a wave seems processed and the site responds for a few seconds before it repeats. During this hick up the database server load spikes while the front end is relaxing. I have looked at slow queries, but is not finding any locks or other unusual queries ran at this time. I have looked at iotop at the time of the halt and there is no activity from mysql. I also tried turning off query_cache and messed around with the mysql configuration file without much change. Any ideas?

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  • How to copy a large LVM volume (14TB) from one server to another?

    - by bruce
    I have to copy a very large LVM volume from server A to server B. Below is the filesystem of server A and server B Server A [root@AVDVD-Filer ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_avdvdfiler-lv_root 16T 14T 1.5T 91% / tmpfs 3.0G 0 3.0G 0% /dev/shm /dev/cciss/c0d0p1 194M 23M 162M 13% /boot /dev/mapper/vg_avdvdfiler-test 2.3T 201M 2.1T 1% /test /dev/sr0 3.3G 3.3G 0 100% /mnt server B [root@localhost ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup-LogVol00 20G 2.5G 16G 14% / tmpfs 3.0G 0 3.0G 0% /dev/shm /dev/cciss/c0d0p1 194M 23M 162M 13% /boot /dev/mapper/VolGroup00-LogVol00 16T 133M 15T 1% /xiangao/lv1 /dev/mapper/VolGroup00-LogVol01 4.7T 190M 4.5T 1% /xiangao/lv2 I want to copy the LVM volume /dev/mapper/vg_avdvdfiler-lv_root on server A to LVM volume /dev/mapper/VolGroup00-LogVol00 on server B. Server A and server B are in the same IP segment. In the LVM volume on server A, there is all average 500M avi wmv mp4 etc. I tried mounting /dev/mapper/vg_avdvdfiler-lv_root on server A to server B through NFS, then use cp to copy. It is clear I failed. Because the LVM volume is too big, I do not have good idea why. I hope a good solution here.

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  • Is it possible to ack nagios alerts from the terminal on a remote workstation?

    - by cat pants
    I have nagios alerts set up to come through jabber with an http link to ack. Is is possible there is a script I can run from a terminal on a remote workstation that takes the hostname as a parameter and acks the alert? ./ack hostname The benefit, while seemingly mundane, is threefold. First, take http load off nagios. Secondly, nagios http pages can take up to 10-20 seconds to load, so I want to save time there. Thirdly, avoiding slower use of mouse + web interface + firefox/other annoyingly slow browser. Ideally, I would like a script bound to a keyboard shortcut that simply acks the most recent alert. Finally, I want to take the inputs from a joystick, buttons and whatnot, and connect one to a big red button bound to the script so I can just ack the most recent nagios alert by hitting the button lol. (It would be rad too if the button had a screen on the enclosure that showed the text of the alert getting acked lol) Make fun of me all you want, but this is actually something that would be useful to me. If I can save five seconds per alert, and I get 200 alerts per day I need to ack, that's saving me 15 minutes a day. And isn't the whole point of the sysadmin to automate what can be automated? Thanks!

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  • Partition Magic 8 made TrueCrypt partition invisible

    - by gmancoda
    Partition Magic 8 took a dump on my TrueCrypt partition... and I let it happen! And now I am left with cleaning up the mess. In short, my encrypted partition is now invisible. TestDisk analysis says of the disk containing the encrypted partition: "Space conflict between the following two partitions". From the googling and searching on various sites, I have learned the following: Hex editing is beyond me. Partition recovery tools are useless. I am not ready to drop the big bucks for professional help. ... that I should have kept an external backup of the Volume header. Now, to get back the volume header, I am planning on recreating the exact same partitions on a new disk of the exact same model, and then encrypting it with the exact same password/keyfiles, and then exporting its volume header to a file. Finally, I hope to be able to restore this volume header on to my damaged drive. Before I undertake this plan, I would like to know if anyone else out there has tried it and, if so, how successful they were. All other suggestions and tips and welcome!! Thanks.

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  • How to minimize the risk of employees spreading critical information? [closed]

    - by Industrial
    What's common sense when it comes to minimising the risk of employees spreading critical information to rivalling companies? As of today, it's clear that not even the US government and military can be sure that their data stays safely within their doors. Thereby I understand that my question probably instead should be written as "What is common sense to make it harder for employees to spread business critical information?" If anyone would want to spread information, they will find a way. That's the way life work and always has. If we make the scenario a bit more realistic by narrowing our workforce by assuming we only have regular John Does onboard and not Linux-loving sysadmins , what should be good precautions to at least make it harder for the employees to send business-critical information to the competition? As far as I can tell, there's a few obvious solutions that clearly has both pros and cons: Block services such as Dropbox and similar, preventing anyone to send gigabytes of data through the wire. Ensure that only files below a set size can be sent as email (?) Setup VLANs between departments to make it harder for kleptomaniacs and curious people to snoop around. Plug all removable media units - CD/DVD, Floppy drives and USB Make sure that no configurations to hardware can be made (?) Monitor network traffic for non-linear events (how?) What is realistic to do in a real world? How does big companies handle this? Sure, we can take the former employer to court and sue, but by then the damage has already been caused... Thanks a lot

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  • Linux Server partitioning

    - by user1717735
    There's a lot of infos about this out there, but there's also a lot of contradictory infos… That's why i need some advices about it. So far, on the servers i had home for test (or even "home production") purposes i didn't really care about partitioning and i configured all in / + a swap partition, over RAID 0. Nevertheless, this pattern can't apply to production servers. I have found a good starting point here, but also it depends on what the servers will be used for… So basically, i have a server on which there will be apache, php, mysql. It will have to handle file uploads (up to 2GB) and has 2*2TB hard drive. I plan to set : / 100GB, /var 1000GB (apache files and mysql files will be here), /tmp 800GB (handles the php tmp file) /home 96GB swap 4GB All of this if of course over RAID 1. But actually, it's not a big deal if I lose data being uploaded, so would it be interesting mounting /tmp over raid 0 while maintaining the rest over raid 1? Sounds complicated…

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  • Benchmark Linq2SQL, Subsonic2, Subsonic3 - Any other ideas to make them faster ?

    - by Aristos
    I am working with Subsonic 2 more than 3 years now... After Linq appears and then Subsonic 3, I start thinking about moving to the new Linq futures that are connected to sql. I must say that I start move and port my subsonic 2 with SubSonic 3, and very soon I discover that the speed was so slow thats I didn't believe it - and starts all that tests. Then I test Linq2Sql and see also a delay - compare it with Subsonic 2. My question here is, especial for the linq2sql, and the up-coming dotnet version 4, what else can I do to speed it up ? What else on linq2sql settings, or classes, not on this code that I have used for my messures I place here the project that I make the tests, also the screen shots of the results. How I make the tests - and the accurate of my measures. I use only for my question Google chrome, because its difficult for me to show here a lot of other measures that I have done with more complex programs. This is the most simple one, I just measure the Data Read. How can I prove that. I make a simple Thread.Sleep(10 seconds) and see if I see that 10 seconds on Google Chrome Measure, and yes I see it. here are more test with this Sleep thead to see whats actually Chrome gives. 10 seconds delay 100 ms delay Zero delay There is only a small 15ms thats get on messure, is so small compare it with the rest of my tests that I do not care about. So what I measure I measure just the data read via each method - did not count the data or database delay, or any disk read or anything like that. Later on the image with the result I show that no disk activity exist on the measures See this image to see what really I measure and if this is correct Why I chose this kind of test Its simple, it's real, and it's near my real problem that I found the delay of subsonic 3 in real program with real data. Now lets tests the dals Start by see this image I have 4-5 calls on every method, the one after the other. The results are. For a loop of 100 times, ask for 5 Rows, one not exist, approximatively.. Simple adonet:81ms SubSonic 2 :210ms linq2sql :1.70sec linq2sql using CompiledQuery.Compile :239ms Subsonic 3 :15.00sec (wow - extreme slow) The project http://www.planethost.gr/DalSpeedTests.rar Can any one confirm this benchmark, or make any optimizations to help me out ? Other tests Some one publish here this link http://ormbattle.net/ (and then remove it - don not know why) In this page you can find a really useful advanced tests for all, except subsonic 2 and subsonic 3 that I have here ! Optimizing What I really ask here is if some one can now any trick how to optimize the DALs, not by changing the test code, but by changing the code and the settings on each dal. For example... Optimizing Linq2SQL I start search how to optimize Linq2sql and found this article, and maybe more exist. Finally I make the tricks from that page to run, and optimize the code using them all. The speed was near 1.50sec from 1.70.... big improvement, but still slow. Then I found a different way - same idea article, and wow ! the speed is blow up. Using this trick with CompiledQuery.Compile, the time from 1.5sec is now 239ms. Here is the code for the precompiled... Func<DataClassesDataContext, int, IQueryable<Product>> compiledQuery = CompiledQuery.Compile((DataClassesDataContext meta, int IdToFind) => (from myData in meta.Products where myData.ProductID.Equals(IdToFind) select myData)); StringBuilder Test = new StringBuilder(); int[] MiaSeira = { 5, 6, 10, 100, 7 }; using (DataClassesDataContext context = new DataClassesDataContext()) { context.ObjectTrackingEnabled = false; for (int i = 0; i < 100; i++) { foreach (int EnaID in MiaSeira) { var oFindThat2P = compiledQuery(context, EnaID); foreach (Product One in oFindThat2P) { Test.Append("<br />"); Test.Append(One.ProductName); } } } } Optimizing SubSonic 3 and problems I make many performance profiling, and start change the one after the other and the speed is better but still too slow. I post them on subsonic group but they ignore the problem, they say that everything is fast... Here is some capture of my profiling and delay points inside subsonic source code I have end up that subsonic3 make more call on the structure of the database rather than on data itself. Needs to reconsider the hole way of asking for data, and follow the subsonic2 idea if this is possible. Try to make precompile to subsonic 3 like I did in linq2Sql but fail for the moment... Optimizing SubSonic 2 After I discover that subsonic 3 is extreme slow, I start my checks on subsonic 2 - that I have never done before believing that is fast. (and it is) So its come up with some points that can be faster. For example there are many loops like this ones that actually is slow because of string manipulation and compares inside the loop. I must say to you that this code called million of times ! on a period of few minutes ! of data asking from the program. On small amount of tables and small fields maybe this is not a big think for some people, but on large amount of tables, the delay is even more. So I decide and optimize the subsonic 2 by my self, by replacing the string compares, with number compares! Simple. I do that almost on every point that profiler say that is slow. I change also all small points that can be even a little faster, and disable some not so used thinks. The results, 5% faster on NorthWind database, near 20% faster on my database with 250 tables. That is count with 500ms less in 10 seconds process on northwind, 100ms faster on my database on 500ms process time. I do not have captures to show you for that because I have made them with different code, different time, and track them down on paper. Anyway this is my story and my question on all that, what else do you know to make them even faster... For this measures I have use Subsonic 2.2 optimized by me, Subsonic 3.0.0.3 a little optimized by me, and Dot.Net 3.5

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  • RESTful services architecture question

    - by abovesun
    This is question more about service architecture strategy, we are building big web system based on rest services on back end. And we are currently trying to build some standard internal to follow while developing rest services. Some queries returns list of entities, for example lets consider we have image galleries retrieving service: /gell_all_galeries, returning next response: <galleries> <gallery> <id>some_gallery_id</id> <name>my photos</name> <photos> <photo> <id>123</id> <name>my photo</name> <location>http://mysite/photo/show/123</location> ...... <author> <id>some_id</id> <name>some name</name> ....... <author> </photo> <photo> ..... </photo> <photo> ..... </photo> <photo> ..... </photo> <photo> ..... </photo> </photos> </gallery> <gallery> .... </gallery> <gallery> .... </gallery> <gallery> .... </gallery> <gallery> .... </gallery> </galleries> As you see here, response quite big and heavy, and not always we need such deep info level. Usual solution is to use or http://ru.wikipedia.org/wiki/Atom elements for each gallery instead of full gallery data: <galleries> <gallery> <id>some_gallery_id</id> <link href="http://mysite/gallery/some_gallery_id"/> </gallery> <gallery> <id>second_gallery_id</id> <link href="http://mysite/gallery/second_gallery_id"/> </gallery> <gallery> .... </gallery> <gallery> .... </gallery> <gallery> .... </gallery> <gallery> .... </gallery> </galleries> The first question, is next: maybe instead we shouldn't even use and types, and just use generic and for all resources that return list objects: <list> <item><link href="http://mysite/gallery/some_gallery_id"/></item> <item><link href="http://mysite/gallery/other_gallery_id"/></item> <item>....</item> </list> And the second question, after user try to retrieve info about some concrete gallery, he'll use for example http://mysite/gallery/some_gallery_id link, what should he see as results? Should it be: <gallery> <id>some_gallery_id</id> <name>my photos</name> <photos> <photo> <id>123</id> <name>my photo</name> <location>http://mysite/photo/show/123</location> ...... <author> <id>some_id</id> <name>some name</name> ....... <author> </photo> <photo> ..... </photo> <photo> ..... </photo> <photo> ..... </photo> <photo> ..... </photo> </photos> </gallery> or : <gallery> <id>some_gallery_id</id> <name>my photos</name> <photos> <photo><link href="http://mysite/photo/11111"/></photo> <photo><link href="http://mysite/photo/22222"/></photo> <photo><link href="http://mysite/photo/33333"/> </photo> <photo> ..... </photo> </photos> </gallery> or <gallery> <id>some_gallery_id</id> <name>my photos</name> <photos> <photo> <link href="http://mysite/photo/11111"/> <author> <link href="http://mysite/author/11111"/> </author> </photo> <photo> <link href="http://mysite/photo/22222"/> <author> <link href="http://mysite/author/11111"/> </author> </photo> <photo> <link href="http://mysite/photo/33333"/> <author> <link href="http://mysite/author/11111"/> </author> </photo> <photo> ..... </photo> </photos> </gallery> I mean if we use link instead of full object info, how deep we should go there? Should I show an author inside photo and so on. Probably my question ambiguous, but what I'm trying to do is create general strategy in such cases for all team members to follow in future.

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  • how to update database table in sqlite3 iphone

    - by Ajeet Kumar Yadav
    Hi I am new in Iphone i am developing application that is use database but i am face problem. In My application I am using table view. I am fetch the value from database in the table view this is done after that we also insert value throw text field in that table of database and display that value in table view.I am also use another table in database table name is Alootikki the value of table alootikki is display in other table view in application and user want to add this table alootikki value in first table of database and display that value in table view when we do this value is display only in the table view this is not write in the database table. when value is display and user want to add other data throw text field then only that add value is show first value is remove from table view. I am not able to solve this plz help me. The code is given bellow for database -(void)Data1 { //////databaseName = @"dataa.sqlite"; databaseName = @"Recipe1.sqlite"; NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDir = [documentPaths objectAtIndex:0]; databasePath =[documentsDir stringByAppendingPathComponent:databaseName]; [self checkAndCreateDatabase]; list1 = [[NSMutableArray alloc] init]; sqlite3 *database; if (sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) { if(addStmt == nil) { ////////////const char *sql = "insert into Dataa(item) Values(?)"; const char *sql = " insert into Slist(Incredients ) Values(?)"; if(sqlite3_prepare_v2(database, sql, -1, &addStmt, NULL) != SQLITE_OK) NSAssert1(0, @"Error while creating add statement. '%s'", sqlite3_errmsg(database)); } sqlite3_bind_text(addStmt, 1, [i UTF8String], -1, SQLITE_TRANSIENT); //sqlite3_bind_int(addStmt,1,i); // sqlite3_bind_text(addStmt, 1, [coffeeName UTF8String], -1, SQLITE_TRANSIENT); // sqlite3_bind_double(addStmt, 2, [price doubleValue]); if(SQLITE_DONE != sqlite3_step(addStmt)) NSAssert1(0, @"Error while inserting data. '%s'", sqlite3_errmsg(database)); else //SQLite provides a method to get the last primary key inserted by using sqlite3_last_insert_rowid coffeeID = sqlite3_last_insert_rowid(database); //Reset the add statement. sqlite3_reset(addStmt); // sqlite3_clear_bindings(detailStmt); //} } sqlite3_finalize(addStmt); addStmt = nil; sqlite3_close(database); } -(void)sopinglist { databaseName= @"Recipe1.sqlite"; NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDir = [documentPaths objectAtIndex:0]; databasePath =[documentsDir stringByAppendingPathComponent:databaseName]; [self checkAndCreateDatabase]; list1 = [[NSMutableArray alloc] init]; sqlite3 *database; if (sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) { if(addStmt == nil) { ///////////const char *sql = "insert into Dataa(item) Values(?)"; const char *sql = " insert into Slist(Incredients,Recipename,foodtype ) Values(?,?,?)"; ///////////// const char *sql =" Update Slist ( Incredients, Recipename,foodtype) Values(?,?,?)"; if(sqlite3_prepare_v2(database, sql, -1, &addStmt, NULL) != SQLITE_OK) NSAssert1(0, @"Error while creating add statement. '%s'", sqlite3_errmsg(database)); } /////for( NSString * j in k) sqlite3_bind_text(addStmt, 1, [k UTF8String], -1, SQLITE_TRANSIENT); //sqlite3_bind_int(addStmt,1,i); // sqlite3_bind_text(addStmt, 1, [coffeeName UTF8String], -1, SQLITE_TRANSIENT); // sqlite3_bind_double(addStmt, 2, [price doubleValue]); if(SQLITE_DONE != sqlite3_step(addStmt)) NSAssert1(0, @"Error while inserting data. '%s'", sqlite3_errmsg(database)); else //SQLite provides a method to get the last primary key inserted by using sqlite3_last_insert_rowid coffeeID = sqlite3_last_insert_rowid(database); //Reset the add statement. sqlite3_reset(addStmt); // sqlite3_clear_bindings(detailStmt); //} } sqlite3_finalize(addStmt); addStmt = nil; sqlite3_close(database); } -(void)Data { ////////////////databaseName = @"dataa.sqlite"; databaseName = @"Recipe1.sqlite"; NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDir = [documentPaths objectAtIndex:0]; databasePath =[documentsDir stringByAppendingPathComponent:databaseName]; [self checkAndCreateDatabase]; list1 = [[NSMutableArray alloc] init]; sqlite3 *database; if (sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) { if(detailStmt == nil) { const char *sql = "Select * from Slist "; if(sqlite3_prepare_v2(database, sql, -1, &detailStmt, NULL) == SQLITE_OK) { //NSLog(@"Hiiiiiii"); //sqlite3_bind_text(detailStmt, 1, [t1 UTF8String], -1, SQLITE_TRANSIENT); //sqlite3_bind_text(detailStmt, 2, [t2 UTF8String], -2, SQLITE_TRANSIENT); //sqlite3_bind_int(detailStmt, 3, t3); while(sqlite3_step(detailStmt) == SQLITE_ROW) { NSLog(@"Helllloooooo"); //NSString *item= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 0)]; NSString *item= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 0)]; char *str=( char*)sqlite3_column_text(detailStmt, 0); if( str) { item = [ NSString stringWithUTF8String:str ]; } else { item= @""; } //+ (NSString*)stringWithCharsIfNotNull: (char*)item /// { // if ( item == NULL ) // return nil; //else // return [[NSString stringWithUTF8String: item] //stringByTrimmingCharactersInSet: [NSCharacterSet whitespaceAndNewlineCharacterSet]]; //} //NSString *fame= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 1)]; //NSString *cinemax = [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 2)]; //NSString *big= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 3)]; //pvr1 = pvr; item1=item; //NSLog(@"%@",item1); data = [[NSMutableArray alloc] init]; list *animal=[[list alloc] initWithName:item1]; // Add the animal object to the animals Array [list1 addObject:animal]; //[list1 addObject:item]; } sqlite3_reset(detailStmt); } sqlite3_finalize(detailStmt); // sqlite3_clear_bindings(detailStmt); } } detailStmt = nil; sqlite3_close(database); } (void)recpies { /////////////////////databaseName = @"Data.sqlite"; databaseName = @"Recipe1.sqlite"; NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDir = [documentPaths objectAtIndex:0]; databasePath =[documentsDir stringByAppendingPathComponent:databaseName]; [self checkAndCreateDatabase]; list1 = [[NSMutableArray alloc] init]; sqlite3 *database; if (sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) { if(detailStmt == nil) { //////const char *sql = "Select * from Dataa"; const char *sql ="select *from alootikki"; if(sqlite3_prepare_v2(database, sql, -1, &detailStmt, NULL) == SQLITE_OK) { //NSLog(@"Hiiiiiii"); //sqlite3_bind_text(detailStmt, 1, [t1 UTF8String], -1, SQLITE_TRANSIENT); //sqlite3_bind_text(detailStmt, 2, [t2 UTF8String], -2, SQLITE_TRANSIENT); //sqlite3_bind_int(detailStmt, 3, t3); while(sqlite3_step(detailStmt) == SQLITE_ROW) { //NSLog(@"Helllloooooo"); //NSString *item= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 0)]; NSString *item= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 0)]; char *str=( char*)sqlite3_column_text(detailStmt, 0); if( str) { item = [ NSString stringWithUTF8String:str ]; } else { item= @""; } //NSString *fame= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 1)]; //NSString *cinemax = [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 2)]; //NSString *big= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 3)]; //pvr1 = pvr; item1=item; //NSLog(@"%@",item1); data = [[NSMutableArray alloc] init]; list *animal=[[list alloc] initWithName:item1]; // Add the animal object to the animals Array [list1 addObject:animal]; //[list1 addObject:item]; } sqlite3_reset(detailStmt); } sqlite3_finalize(detailStmt); // sqlite3_clear_bindings(detailStmt); } } detailStmt = nil; sqlite3_close(database); }

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  • SQL SERVER – Shrinking NDF and MDF Files – Readers’ Opinion

    - by pinaldave
    Previously, I had written a blog post about SQL SERVER – Shrinking NDF and MDF Files – A Safe Operation. After that, I have written the following blog post that talks about the advantage and disadvantage of Shrinking and why one should not be Shrinking a file SQL SERVER – SHRINKFILE and TRUNCATE Log File in SQL Server 2008. On this subject, SQL Server Expert Imran Mohammed left an excellent comment. I just feel that his comment is worth a big article itself. For everybody to read his wonderful explanation, I am posting this blog post here. Thanks Imran! Shrinking Database always creates performance degradation and increases fragmentation in the database. I suggest that you keep that in mind before you start reading the following comment. If you are going to say Shrinking Database is bad and evil, here I am saying it first and loud. Now, the comment of Imran is written while keeping in mind only the process showing how the Shrinking Database Operation works. Imran has already explained his understanding and requests further explanation. I have removed the Best Practices section from Imran’s comments, as there are a few corrections. Comments from Imran - Before I explain to you the concept of Shrink Database, let us understand the concept of Database Files. When we create a new database inside the SQL Server, it is typical that SQl Server creates two physical files in the Operating System: one with .MDF Extension, and another with .LDF Extension. .MDF is called as Primary Data File. .LDF is called as Transactional Log file. If you add one or more data files to a database, the physical file that will be created in the Operating System will have an extension of .NDF, which is called as Secondary Data File; whereas, when you add one or more log files to a database, the physical file that will be created in the Operating System will have the same extension as .LDF. The questions now are, “Why does a new data file have a different extension (.NDF)?”, “Why is it called as a secondary data file?” and, “Why is .MDF file called as a primary data file?” Answers: Note: The following explanation is based on my limited knowledge of SQL Server, so experts please do comment. A data file with a .MDF extension is called a Primary Data File, and the reason behind it is that it contains Database Catalogs. Catalogs mean Meta Data. Meta Data is “Data about Data”. An example for Meta Data includes system objects that store information about other objects, except the data stored by the users. sysobjects stores information about all objects in that database. sysindexes stores information about all indexes and rows of every table in that database. syscolumns stores information about all columns that each table has in that database. sysusers stores how many users that database has. Although Meta Data stores information about other objects, it is not the transactional data that a user enters; rather, it’s a system data about the data. Because Primary Data File (.MDF) contains important information about the database, it is treated as a special file. It is given the name Primary Data file because it contains the Database Catalogs. This file is present in the Primary File Group. You can always create additional objects (Tables, indexes etc.) in the Primary data file (This file is present in the Primary File group), by mentioning that you want to create this object under the Primary File Group. Any additional data file that you add to the database will have only transactional data but no Meta Data, so that’s why it is called as the Secondary Data File. It is given the extension name .NDF so that the user can easily identify whether a specific data file is a Primary Data File or a Secondary Data File(s). There are many advantages of storing data in different files that are under different file groups. You can put your read only in the tables in one file (file group) and read-write tables in another file (file group) and take a backup of only the file group that has read the write data, so that you can avoid taking the backup of a read-only data that cannot be altered. Creating additional files in different physical hard disks also improves I/O performance. A real-time scenario where we use Files could be this one: Let’s say you have created a database called MYDB in the D-Drive which has a 50 GB space. You also have 1 Database File (.MDF) and 1 Log File on D-Drive and suppose that all of that 50 GB space has been used up and you do not have any free space left but you still want to add an additional space to the database. One easy option would be to add one more physical hard disk to the server, add new data file to MYDB database and create this new data file in a new hard disk then move some of the objects from one file to another, and put the file group under which you added new file as default File group, so that any new object that is created gets into the new files, unless specified. Now that we got a basic idea of what data files are, what type of data they store and why they are named the way they are, let’s move on to the next topic, Shrinking. First of all, I disagree with the Microsoft terminology for naming this feature as “Shrinking”. Shrinking, in regular terms, means to reduce the size of a file by means of compressing it. BUT in SQL Server, Shrinking DOES NOT mean compressing. Shrinking in SQL Server means to remove an empty space from database files and release the empty space either to the Operating System or to SQL Server. Let’s examine this through an example. Let’s say you have a database “MYDB” with a size of 50 GB that has a free space of about 20 GB, which means 30GB in the database is filled with data and the 20 GB of space is free in the database because it is not currently utilized by the SQL Server (Database); it is reserved and not yet in use. If you choose to shrink the database and to release an empty space to Operating System, and MIND YOU, you can only shrink the database size to 30 GB (in our example). You cannot shrink the database to a size less than what is filled with data. So, if you have a database that is full and has no empty space in the data file and log file (you don’t have an extra disk space to set Auto growth option ON), YOU CANNOT issue the SHRINK Database/File command, because of two reasons: There is no empty space to be released because the Shrink command does not compress the database; it only removes the empty space from the database files and there is no empty space. Remember, the Shrink command is a logged operation. When we perform the Shrink operation, this information is logged in the log file. If there is no empty space in the log file, SQL Server cannot write to the log file and you cannot shrink a database. Now answering your questions: (1) Q: What are the USEDPAGES & ESTIMATEDPAGES that appear on the Results Pane after using the DBCC SHRINKDATABASE (NorthWind, 10) ? A: According to Books Online (For SQL Server 2000): UsedPages: the number of 8-KB pages currently used by the file. EstimatedPages: the number of 8-KB pages that SQL Server estimates the file could be shrunk down to. Important Note: Before asking any question, make sure you go through Books Online or search on the Google once. The reasons for doing so have many advantages: 1. If someone else already has had this question before, chances that it is already answered are more than 50 %. 2. This reduces your waiting time for the answer. (2) Q: What is the difference between Shrinking the Database using DBCC command like the one above & shrinking it from the Enterprise Manager Console by Right-Clicking the database, going to TASKS & then selecting SHRINK Option, on a SQL Server 2000 environment? A: As far as my knowledge goes, there is no difference, both will work the same way, one advantage of using this command from query analyzer is, your console won’t be freezed. You can do perform your regular activities using Enterprise Manager. (3) Q: What is this .NDF file that is discussed above? I have never heard of it. What is it used for? Is it used by end-users, DBAs or the SERVER/SYSTEM itself? A: .NDF File is a secondary data file. You never heard of it because when database is created, SQL Server creates database by default with only 1 data file (.MDF) and 1 log file (.LDF) or however your model database has been setup, because a model database is a template used every time you create a new database using the CREATE DATABASE Command. Unless you have added an extra data file, you will not see it. This file is used by the SQL Server to store data which are saved by the users. Hope this information helps. I would like to as the experts to please comment if what I understand is not what the Microsoft guys meant. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Readers Contribution, Readers Question, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Capturing and Transforming ASP.NET Output with Response.Filter

    - by Rick Strahl
    During one of my Handlers and Modules session at DevConnections this week one of the attendees asked a question that I didn’t have an immediate answer for. Basically he wanted to capture response output completely and then apply some filtering to the output – effectively injecting some additional content into the page AFTER the page had completely rendered. Specifically the output should be captured from anywhere – not just a page and have this code injected into the page. Some time ago I posted some code that allows you to capture ASP.NET Page output by overriding the Render() method, capturing the HtmlTextWriter() and reading its content, modifying the rendered data as text then writing it back out. I’ve actually used this approach on a few occasions and it works fine for ASP.NET pages. But this obviously won’t work outside of the Page class environment and it’s not really generic – you have to create a custom page class in order to handle the output capture. [updated 11/16/2009 – updated ResponseFilterStream implementation and a few additional notes based on comments] Enter Response.Filter However, ASP.NET includes a Response.Filter which can be used – well to filter output. Basically Response.Filter is a stream through which the OutputStream is piped back to the Web Server (indirectly). As content is written into the Response object, the filter stream receives the appropriate Stream commands like Write, Flush and Close as well as read operations although for a Response.Filter that’s uncommon to be hit. The Response.Filter can be programmatically replaced at runtime which allows you to effectively intercept all output generation that runs through ASP.NET. A common Example: Dynamic GZip Encoding A rather common use of Response.Filter hooking up code based, dynamic  GZip compression for requests which is dead simple by applying a GZipStream (or DeflateStream) to Response.Filter. The following generic routines can be used very easily to detect GZip capability of the client and compress response output with a single line of code and a couple of library helper routines: WebUtils.GZipEncodePage(); which is handled with a few lines of reusable code and a couple of static helper methods: /// <summary> ///Sets up the current page or handler to use GZip through a Response.Filter ///IMPORTANT:  ///You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() {     HttpResponse Response = HttpContext.Current.Response;     if(IsGZipSupported())     {         stringAcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"];         if(AcceptEncoding.Contains("deflate"))         {             Response.Filter = newSystem.IO.Compression.DeflateStream(Response.Filter,                                        System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "deflate");         }         else        {             Response.Filter = newSystem.IO.Compression.GZipStream(Response.Filter,                                       System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "gzip");                            }     }     // Allow proxy servers to cache encoded and unencoded versions separately    Response.AppendHeader("Vary", "Content-Encoding"); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } GZipStream and DeflateStream are streams that are assigned to Response.Filter and by doing so apply the appropriate compression on the active Response. Response.Filter content is chunked So to implement a Response.Filter effectively requires only that you implement a custom stream and handle the Write() method to capture Response output as it’s written. At first blush this seems very simple – you capture the output in Write, transform it and write out the transformed content in one pass. And that indeed works for small amounts of content. But you see, the problem is that output is written in small buffer chunks (a little less than 16k it appears) rather than just a single Write() statement into the stream, which makes perfect sense for ASP.NET to stream data back to IIS in smaller chunks to minimize memory usage en route. Unfortunately this also makes it a more difficult to implement any filtering routines since you don’t directly get access to all of the response content which is problematic especially if those filtering routines require you to look at the ENTIRE response in order to transform or capture the output as is needed for the solution the gentleman in my session asked for. So in order to address this a slightly different approach is required that basically captures all the Write() buffers passed into a cached stream and then making the stream available only when it’s complete and ready to be flushed. As I was thinking about the implementation I also started thinking about the few instances when I’ve used Response.Filter implementations. Each time I had to create a new Stream subclass and create my custom functionality but in the end each implementation did the same thing – capturing output and transforming it. I thought there should be an easier way to do this by creating a re-usable Stream class that can handle stream transformations that are common to Response.Filter implementations. Creating a semi-generic Response Filter Stream Class What I ended up with is a ResponseFilterStream class that provides a handful of Events that allow you to capture and/or transform Response content. The class implements a subclass of Stream and then overrides Write() and Flush() to handle capturing and transformation operations. By exposing events it’s easy to hook up capture or transformation operations via single focused methods. ResponseFilterStream exposes the following events: CaptureStream, CaptureString Captures the output only and provides either a MemoryStream or String with the final page output. Capture is hooked to the Flush() operation of the stream. TransformStream, TransformString Allows you to transform the complete response output with events that receive a MemoryStream or String respectively and can you modify the output then return it back as a return value. The transformed output is then written back out in a single chunk to the response output stream. These events capture all output internally first then write the entire buffer into the response. TransformWrite, TransformWriteString Allows you to transform the Response data as it is written in its original chunk size in the Stream’s Write() method. Unlike TransformStream/TransformString which operate on the complete output, these events only see the current chunk of data written. This is more efficient as there’s no caching involved, but can cause problems due to searched content splitting over multiple chunks. Using this implementation, creating a custom Response.Filter transformation becomes as simple as the following code. To hook up the Response.Filter using the MemoryStream version event: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformStream += filter_TransformStream; Response.Filter = filter; and the event handler to do the transformation: MemoryStream filter_TransformStream(MemoryStream ms) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = encoding.GetString(ms.ToArray()); output = FixPaths(output); ms = new MemoryStream(output.Length); byte[] buffer = encoding.GetBytes(output); ms.Write(buffer,0,buffer.Length); return ms; } private string FixPaths(string output) { string path = HttpContext.Current.Request.ApplicationPath; // override root path wonkiness if (path == "/") path = ""; output = output.Replace("\"~/", "\"" + path + "/").Replace("'~/", "'" + path + "/"); return output; } The idea of the event handler is that you can do whatever you want to the stream and return back a stream – either the same one that’s been modified or a brand new one – which is then sent back to as the final response. The above code can be simplified even more by using the string version events which handle the stream to string conversions for you: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; and the event handler to do the transformation calling the same FixPaths method shown above: string filter_TransformString(string output) { return FixPaths(output); } The events for capturing output and capturing and transforming chunks work in a very similar way. By using events to handle the transformations ResponseFilterStream becomes a reusable component and we don’t have to create a new stream class or subclass an existing Stream based classed. By the way, the example used here is kind of a cool trick which transforms “~/” expressions inside of the final generated HTML output – even in plain HTML controls not HTML controls – and transforms them into the appropriate application relative path in the same way that ResolveUrl would do. So you can write plain old HTML like this: <a href=”~/default.aspx”>Home</a>  and have it turned into: <a href=”/myVirtual/default.aspx”>Home</a>  without having to use an ASP.NET control like Hyperlink or Image or having to constantly use: <img src=”<%= ResolveUrl(“~/images/home.gif”) %>” /> in MVC applications (which frankly is one of the most annoying things about MVC especially given the path hell that extension-less and endpoint-less URLs impose). I can’t take credit for this idea. While discussing the Response.Filter issues on Twitter a hint from Dylan Beattie who pointed me at one of his examples which does something similar. I thought the idea was cool enough to use an example for future demos of Response.Filter functionality in ASP.NET next I time I do the Modules and Handlers talk (which was great fun BTW). How practical this is is debatable however since there’s definitely some overhead to using a Response.Filter in general and especially on one that caches the output and the re-writes it later. Make sure to test for performance anytime you use Response.Filter hookup and make sure it' doesn’t end up killing perf on you. You’ve been warned :-}. How does ResponseFilterStream work? The big win of this implementation IMHO is that it’s a reusable  component – so for implementation there’s no new class, no subclassing – you simply attach to an event to implement an event handler method with a straight forward signature to retrieve the stream or string you’re interested in. The implementation is based on a subclass of Stream as is required in order to handle the Response.Filter requirements. What’s different than other implementations I’ve seen in various places is that it supports capturing output as a whole to allow retrieving the full response output for capture or modification. The exception are the TransformWrite and TransformWrite events which operate only active chunk of data written by the Response. For captured output, the Write() method captures output into an internal MemoryStream that is cached until writing is complete. So Write() is called when ASP.NET writes to the Response stream, but the filter doesn’t pass on the Write immediately to the filter’s internal stream. The data is cached and only when the Flush() method is called to finalize the Stream’s output do we actually send the cached stream off for transformation (if the events are hooked up) and THEN finally write out the returned content in one big chunk. Here’s the implementation of ResponseFilterStream: /// <summary> /// A semi-generic Stream implementation for Response.Filter with /// an event interface for handling Content transformations via /// Stream or String. /// <remarks> /// Use with care for large output as this implementation copies /// the output into a memory stream and so increases memory usage. /// </remarks> /// </summary> public class ResponseFilterStream : Stream { /// <summary> /// The original stream /// </summary> Stream _stream; /// <summary> /// Current position in the original stream /// </summary> long _position; /// <summary> /// Stream that original content is read into /// and then passed to TransformStream function /// </summary> MemoryStream _cacheStream = new MemoryStream(5000); /// <summary> /// Internal pointer that that keeps track of the size /// of the cacheStream /// </summary> int _cachePointer = 0; /// <summary> /// /// </summary> /// <param name="responseStream"></param> public ResponseFilterStream(Stream responseStream) { _stream = responseStream; } /// <summary> /// Determines whether the stream is captured /// </summary> private bool IsCaptured { get { if (CaptureStream != null || CaptureString != null || TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Determines whether the Write method is outputting data immediately /// or delaying output until Flush() is fired. /// </summary> private bool IsOutputDelayed { get { if (TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Event that captures Response output and makes it available /// as a MemoryStream instance. Output is captured but won't /// affect Response output. /// </summary> public event Action<MemoryStream> CaptureStream; /// <summary> /// Event that captures Response output and makes it available /// as a string. Output is captured but won't affect Response output. /// </summary> public event Action<string> CaptureString; /// <summary> /// Event that allows you transform the stream as each chunk of /// the output is written in the Write() operation of the stream. /// This means that that it's possible/likely that the input /// buffer will not contain the full response output but only /// one of potentially many chunks. /// /// This event is called as part of the filter stream's Write() /// operation. /// </summary> public event Func<byte[], byte[]> TransformWrite; /// <summary> /// Event that allows you to transform the response stream as /// each chunk of bytep[] output is written during the stream's write /// operation. This means it's possibly/likely that the string /// passed to the handler only contains a portion of the full /// output. Typical buffer chunks are around 16k a piece. /// /// This event is called as part of the stream's Write operation. /// </summary> public event Func<string, string> TransformWriteString; /// <summary> /// This event allows capturing and transformation of the entire /// output stream by caching all write operations and delaying final /// response output until Flush() is called on the stream. /// </summary> public event Func<MemoryStream, MemoryStream> TransformStream; /// <summary> /// Event that can be hooked up to handle Response.Filter /// Transformation. Passed a string that you can modify and /// return back as a return value. The modified content /// will become the final output. /// </summary> public event Func<string, string> TransformString; protected virtual void OnCaptureStream(MemoryStream ms) { if (CaptureStream != null) CaptureStream(ms); } private void OnCaptureStringInternal(MemoryStream ms) { if (CaptureString != null) { string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); OnCaptureString(content); } } protected virtual void OnCaptureString(string output) { if (CaptureString != null) CaptureString(output); } protected virtual byte[] OnTransformWrite(byte[] buffer) { if (TransformWrite != null) return TransformWrite(buffer); return buffer; } private byte[] OnTransformWriteStringInternal(byte[] buffer) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = OnTransformWriteString(encoding.GetString(buffer)); return encoding.GetBytes(output); } private string OnTransformWriteString(string value) { if (TransformWriteString != null) return TransformWriteString(value); return value; } protected virtual MemoryStream OnTransformCompleteStream(MemoryStream ms) { if (TransformStream != null) return TransformStream(ms); return ms; } /// <summary> /// Allows transforming of strings /// /// Note this handler is internal and not meant to be overridden /// as the TransformString Event has to be hooked up in order /// for this handler to even fire to avoid the overhead of string /// conversion on every pass through. /// </summary> /// <param name="responseText"></param> /// <returns></returns> private string OnTransformCompleteString(string responseText) { if (TransformString != null) TransformString(responseText); return responseText; } /// <summary> /// Wrapper method form OnTransformString that handles /// stream to string and vice versa conversions /// </summary> /// <param name="ms"></param> /// <returns></returns> internal MemoryStream OnTransformCompleteStringInternal(MemoryStream ms) { if (TransformString == null) return ms; //string content = ms.GetAsString(); string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); content = TransformString(content); byte[] buffer = HttpContext.Current.Response.ContentEncoding.GetBytes(content); ms = new MemoryStream(); ms.Write(buffer, 0, buffer.Length); //ms.WriteString(content); return ms; } /// <summary> /// /// </summary> public override bool CanRead { get { return true; } } public override bool CanSeek { get { return true; } } /// <summary> /// /// </summary> public override bool CanWrite { get { return true; } } /// <summary> /// /// </summary> public override long Length { get { return 0; } } /// <summary> /// /// </summary> public override long Position { get { return _position; } set { _position = value; } } /// <summary> /// /// </summary> /// <param name="offset"></param> /// <param name="direction"></param> /// <returns></returns> public override long Seek(long offset, System.IO.SeekOrigin direction) { return _stream.Seek(offset, direction); } /// <summary> /// /// </summary> /// <param name="length"></param> public override void SetLength(long length) { _stream.SetLength(length); } /// <summary> /// /// </summary> public override void Close() { _stream.Close(); } /// <summary> /// Override flush by writing out the cached stream data /// </summary> public override void Flush() { if (IsCaptured && _cacheStream.Length > 0) { // Check for transform implementations _cacheStream = OnTransformCompleteStream(_cacheStream); _cacheStream = OnTransformCompleteStringInternal(_cacheStream); OnCaptureStream(_cacheStream); OnCaptureStringInternal(_cacheStream); // write the stream back out if output was delayed if (IsOutputDelayed) _stream.Write(_cacheStream.ToArray(), 0, (int)_cacheStream.Length); // Clear the cache once we've written it out _cacheStream.SetLength(0); } // default flush behavior _stream.Flush(); } /// <summary> /// /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> /// <returns></returns> public override int Read(byte[] buffer, int offset, int count) { return _stream.Read(buffer, offset, count); } /// <summary> /// Overriden to capture output written by ASP.NET and captured /// into a cached stream that is written out later when Flush() /// is called. /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> public override void Write(byte[] buffer, int offset, int count) { if ( IsCaptured ) { // copy to holding buffer only - we'll write out later _cacheStream.Write(buffer, 0, count); _cachePointer += count; } // just transform this buffer if (TransformWrite != null) buffer = OnTransformWrite(buffer); if (TransformWriteString != null) buffer = OnTransformWriteStringInternal(buffer); if (!IsOutputDelayed) _stream.Write(buffer, offset, buffer.Length); } } The key features are the events and corresponding OnXXX methods that handle the event hookups, and the Write() and Flush() methods of the stream implementation. All the rest of the members tend to be plain jane passthrough stream implementation code without much consequence. I do love the way Action<t> and Func<T> make it so easy to create the event signatures for the various events – sweet. A few Things to consider Performance Response.Filter is not great for performance in general as it adds another layer of indirection to the ASP.NET output pipeline, and this implementation in particular adds a memory hit as it basically duplicates the response output into the cached memory stream which is necessary since you may have to look at the entire response. If you have large pages in particular this can cause potentially serious memory pressure in your server application. So be careful of wholesale adoption of this (or other) Response.Filters. Make sure to do some performance testing to ensure it’s not killing your app’s performance. Response.Filter works everywhere A few questions came up in comments and discussion as to capturing ALL output hitting the site and – yes you can definitely do that by assigning a Response.Filter inside of a module. If you do this however you’ll want to be very careful and decide which content you actually want to capture especially in IIS 7 which passes ALL content – including static images/CSS etc. through the ASP.NET pipeline. So it is important to filter only on what you’re looking for – like the page extension or maybe more effectively the Response.ContentType. Response.Filter Chaining Originally I thought that filter chaining doesn’t work at all due to a bug in the stream implementation code. But it’s quite possible to assign multiple filters to the Response.Filter property. So the following actually works to both compress the output and apply the transformed content: WebUtils.GZipEncodePage(); ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; However the following does not work resulting in invalid content encoding errors: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; WebUtils.GZipEncodePage(); In other words multiple Response filters can work together but it depends entirely on the implementation whether they can be chained or in which order they can be chained. In this case running the GZip/Deflate stream filters apparently relies on the original content length of the output and chokes when the content is modified. But if attaching the compression first it works fine as unintuitive as that may seem. Resources Download example code Capture Output from ASP.NET Pages © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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  • ASP.NET MVC 2 Mdel encapsulated within ViewModel Validation

    - by Program.X
    I am trying to get validation to work in ASP.NET MVC 2, but without much success. I have a complex class containing a large number of fields. (Don't ask - this is oneo f those real-world situations best practices can't touch) This would normally be my Model and is a LINQ-to-SQL generated class. Because this is generated code, I have created a MetaData class as per http://davidhayden.com/blog/dave/archive/2009/08/10/AspNetMvc20BuddyClassesMetadataType.aspx. public class ConsultantRegistrationMetadata { [DisplayName("Title")] [Required(ErrorMessage = "Title is required")] [StringLength(10, ErrorMessage = "Title cannot contain more than 10 characters")] string Title { get; set; } [Required(ErrorMessage = "Forename(s) is required")] [StringLength(128, ErrorMessage = "Forename(s) cannot contain more than 128 characters")] [DisplayName("Forename(s)")] string Forenames { get; set; } // ... I've attached this to the partial class of my generated class: [MetadataType(typeof(ConsultantRegistrationMetadata))] public partial class ConsultantRegistration { // ... Because my form is complex, it has a number of dependencies, such as SelectLists, etc. which I have encapsulated in a ViewModel pattern - and included the ConsultantRegistration model as a property: public class ConsultantRegistrationFormViewModel { public Data.ConsultantRegistration ConsultantRegistration { get; private set; } public SelectList Titles { get; private set; } public SelectList Countries { get; private set; } // ... So it is essentially ViewModel=Model My View then has: <p> <%: Html.LabelFor(model => model.ConsultantRegistration.Title) %> <%: Html.DropDownListFor(model => model.ConsultantRegistration.Title, Model.Titles,"(select a Title)") %> <%: Html.ValidationMessage("Title","*") %> </p> <p> <%: Html.LabelFor(model => model.ConsultantRegistration.Forenames) %> <%: Html.TextBoxFor(model => model.ConsultantRegistration.Forenames) %> <%: Html.ValidationMessageFor(model=>model.ConsultantRegistration.Forenames) %> </p> The problem is, the validation attributes on the metadata class are having no effect. I tried doing it via an Interface, but also no effect. I'm beginning to think that the reason is because I am encapsulating my model within a ViewModel. My Controller (Create Action) is as follows: [HttpPost] public ActionResult Create(Data.ConsultantRegistration consultantRegistration) { if (ModelState.IsValid) // this is always true - which is wrong!! { try { consultantRegistration = ConsultantRegistrationRepository.SaveConsultantRegistration(consultantRegistration); return RedirectToAction("Edit", new { id = consultantRegistration.ID, sectionIndex = 2 }); } catch (Exception ex) { ModelState.AddModelError("CreateException",ex); } } return View(new ConsultantRegistrationFormViewModel(consultantRegistration)); } As outlined in the comment, the ModelState.IsValid property always returns true, despite fields with the Validaiton annotations not being valid. (Forenames being a key example). Am I missing something obvious - considering I am an MVC newbie? I'm after the mechanism demoed by Jon Galloway at http://www.asp.net/learn/mvc-videos/video-10082.aspx. (Am aware t is similar to http://stackoverflow.com/questions/1260562/asp-net-mvc-model-viewmodel-validation but that post seems to talk about xVal. I have no idea what that is and suspect it is for MVC 1)

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  • Web Browser Control &ndash; Specifying the IE Version

    - by Rick Strahl
    I use the Internet Explorer Web Browser Control in a lot of my applications to display document type layout. HTML happens to be one of the most common document formats and displaying data in this format – even in desktop applications, is often way easier than using normal desktop technologies. One issue the Web Browser Control has that it’s perpetually stuck in IE 7 rendering mode by default. Even though IE 8 and now 9 have significantly upgraded the IE rendering engine to be more CSS and HTML compliant by default the Web Browser control will have none of it. IE 9 in particular – with its much improved CSS support and basic HTML 5 support is a big improvement and even though the IE control uses some of IE’s internal rendering technology it’s still stuck in the old IE 7 rendering by default. This applies whether you’re using the Web Browser control in a WPF application, a WinForms app, a FoxPro or VB classic application using the ActiveX control. Behind the scenes all these UI platforms use the COM interfaces and so you’re stuck by those same rules. Rendering Challenged To see what I’m talking about here are two screen shots rendering an HTML 5 doctype page that includes some CSS 3 functionality – rounded corners and border shadows - from an earlier post. One uses IE 9 as a standalone browser, and one uses a simple WPF form that includes the Web Browser control. IE 9 Browser:   Web Browser control in a WPF form: The IE 9 page displays this HTML correctly – you see the rounded corners and shadow displayed. Obviously the latter rendering using the Web Browser control in a WPF application is a bit lacking. Not only are the new CSS features missing but the page also renders in Internet Explorer’s quirks mode so all the margins, padding etc. behave differently by default, even though there’s a CSS reset applied on this page. If you’re building an application that intends to use the Web Browser control for a live preview of some HTML this is clearly undesirable. Feature Delegation via Registry Hacks Fortunately starting with Internet Explore 8 and later there’s a fix for this problem via a registry setting. You can specify a registry key to specify which rendering mode and version of IE should be used by that application. These are not global mind you – they have to be enabled for each application individually. There are two different sets of keys for 32 bit and 64 bit applications. 32 bit: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION Value Key: yourapplication.exe 64 bit: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION Value Key: yourapplication.exe The value to set this key to is (taken from MSDN here) as decimal values: 9999 (0x270F) Internet Explorer 9. Webpages are displayed in IE9 Standards mode, regardless of the !DOCTYPE directive. 9000 (0x2328) Internet Explorer 9. Webpages containing standards-based !DOCTYPE directives are displayed in IE9 mode. 8888 (0x22B8) Webpages are displayed in IE8 Standards mode, regardless of the !DOCTYPE directive. 8000 (0x1F40) Webpages containing standards-based !DOCTYPE directives are displayed in IE8 mode. 7000 (0x1B58) Webpages containing standards-based !DOCTYPE directives are displayed in IE7 Standards mode.   The added key looks something like this in the Registry Editor: With this in place my Html Html Help Builder application which has wwhelp.exe as its main executable now works with HTML 5 and CSS 3 documents in the same way that Internet Explorer 9 does. Incidentally I accidentally added an ‘empty’ DWORD value of 0 to my EXE name and that worked as well giving me IE 9 rendering. Although not documented I suspect 0 (or an invalid value) will default to the installed browser. Don’t have a good way to test this but if somebody could try this with IE 8 installed that would be great: What happens when setting 9000 with IE 8 installed? What happens when setting 0 with IE 8 installed? Don’t forget to add Keys for Host Environments If you’re developing your application in Visual Studio and you run the debugger you may find that your application is still not rendering right, but if you run the actual generated EXE from Explorer or the OS command prompt it works. That’s because when you run the debugger in Visual Studio it wraps your application into a debugging host container. For this reason you might want to also add another registry key for yourapp.vshost.exe on your development machine. If you’re developing in Visual FoxPro make sure you add a key for vfp9.exe to see the rendering adjustments in the Visual FoxPro development environment. Cleaner HTML - no more HTML mangling! There are a number of additional benefits to setting up rendering of the Web Browser control to the IE 9 engine (or even the IE 8 engine) beyond the obvious rendering functionality. IE 9 actually returns your HTML in something that resembles the original HTML formatting, as opposed to the IE 7 default format which mangled the original HTML content. If you do the following in the WPF application: private void button2_Click(object sender, RoutedEventArgs e) { dynamic doc = this.webBrowser.Document; MessageBox.Show(doc.body.outerHtml); } you get different output depending on the rendering mode active. With the default IE 7 rendering you get: <BODY><DIV> <H1>Rounded Corners and Shadows - Creating Dialogs in CSS</H1> <DIV class=toolbarcontainer><A class=hoverbutton href="./"><IMG src="../../css/images/home.gif"> Home</A> <A class=hoverbutton href="RoundedCornersAndShadows.htm"><IMG src="../../css/images/refresh.gif"> Refresh</A> </DIV> <DIV class=containercontent> <FIELDSET><LEGEND>Plain Box</LEGEND><!-- Simple Box with rounded corners and shadow --> <DIV style="BORDER-BOTTOM: steelblue 2px solid; BORDER-LEFT: steelblue 2px solid; WIDTH: 550px; BORDER-TOP: steelblue 2px solid; BORDER-RIGHT: steelblue 2px solid" class="roundbox boxshadow"> <DIV style="BACKGROUND: khaki" class="boxcontenttext roundbox">Simple Rounded Corner Box. </DIV></DIV></FIELDSET> <FIELDSET><LEGEND>Box with Header</LEGEND> <DIV style="BORDER-BOTTOM: steelblue 2px solid; BORDER-LEFT: steelblue 2px solid; WIDTH: 550px; BORDER-TOP: steelblue 2px solid; BORDER-RIGHT: steelblue 2px solid" class="roundbox boxshadow"> <DIV class="gridheaderleft roundbox-top">Box with a Header</DIV> <DIV style="BACKGROUND: khaki" class="boxcontenttext roundbox-bottom">Simple Rounded Corner Box. </DIV></DIV></FIELDSET> <FIELDSET><LEGEND>Dialog Style Window</LEGEND> <DIV style="POSITION: relative; WIDTH: 450px" id=divDialog class="dialog boxshadow" jQuery16107208195684204002="2"> <DIV style="POSITION: relative" class=dialog-header> <DIV class=closebox></DIV>User Sign-in <DIV class=closebox jQuery16107208195684204002="3"></DIV></DIV> <DIV class=descriptionheader>This dialog is draggable and closable</DIV> <DIV class=dialog-content><LABEL>Username:</LABEL> <INPUT name=txtUsername value=" "> <LABEL>Password</LABEL> <INPUT name=txtPassword value=" "> <HR> <INPUT id=btnLogin value=Login type=button> </DIV> <DIV class=dialog-statusbar>Ready</DIV></DIV></FIELDSET> </DIV> <SCRIPT type=text/javascript>     $(document).ready(function () {         $("#divDialog")             .draggable({ handle: ".dialog-header" })             .closable({ handle: ".dialog-header",                 closeHandler: function () {                     alert("Window about to be closed.");                     return true;  // true closes - false leaves open                 }             });     }); </SCRIPT> </DIV></BODY> Now lest you think I’m out of my mind and create complete whacky HTML rooted in the last century, here’s the IE 9 rendering mode output which looks a heck of a lot cleaner and a lot closer to my original HTML of the page I’m accessing: <body> <div>         <h1>Rounded Corners and Shadows - Creating Dialogs in CSS</h1>     <div class="toolbarcontainer">         <a class="hoverbutton" href="./"> <img src="../../css/images/home.gif"> Home</a>         <a class="hoverbutton" href="RoundedCornersAndShadows.htm"> <img src="../../css/images/refresh.gif"> Refresh</a>     </div>         <div class="containercontent">     <fieldset>         <legend>Plain Box</legend>                <!-- Simple Box with rounded corners and shadow -->             <div style="border: 2px solid steelblue; width: 550px;" class="roundbox boxshadow">                              <div style="background: khaki;" class="boxcontenttext roundbox">                     Simple Rounded Corner Box.                 </div>             </div>     </fieldset>     <fieldset>         <legend>Box with Header</legend>         <div style="border: 2px solid steelblue; width: 550px;" class="roundbox boxshadow">                          <div class="gridheaderleft roundbox-top">Box with a Header</div>             <div style="background: khaki;" class="boxcontenttext roundbox-bottom">                 Simple Rounded Corner Box.             </div>         </div>     </fieldset>       <fieldset>         <legend>Dialog Style Window</legend>         <div style="width: 450px; position: relative;" id="divDialog" class="dialog boxshadow">             <div style="position: relative;" class="dialog-header">                 <div class="closebox"></div>                 User Sign-in             <div class="closebox"></div></div>             <div class="descriptionheader">This dialog is draggable and closable</div>                    <div class="dialog-content">                             <label>Username:</label>                 <input name="txtUsername" value=" " type="text">                 <label>Password</label>                 <input name="txtPassword" value=" " type="text">                                 <hr/>                                 <input id="btnLogin" value="Login" type="button">                        </div>             <div class="dialog-statusbar">Ready</div>         </div>     </fieldset>     </div> <script type="text/javascript">     $(document).ready(function () {         $("#divDialog")             .draggable({ handle: ".dialog-header" })             .closable({ handle: ".dialog-header",                 closeHandler: function () {                     alert("Window about to be closed.");                     return true;  // true closes - false leaves open                 }             });     }); </script>        </div> </body> IOW, in IE9 rendering mode IE9 is much closer (but not identical) to the original HTML from the page on the Web that we’re reading from. As a side note: Unfortunately, the browser feature emulation can't be applied against the Html Help (CHM) Engine in Windows which uses the Web Browser control (or COM interfaces anyway) to render Html Help content. I tried setting up hh.exe which is the help viewer, to use IE 9 rendering but a help file generated with CSS3 features will simply show in IE 7 mode. Bummer - this would have been a nice quick fix to allow help content served from CHM files to look better. HTML Editing leaves HTML formatting intact In the same vane, if you do any inline HTML editing in the control by setting content to be editable, IE 9’s control does a much more reasonable job of creating usable and somewhat valid HTML. It also leaves the original content alone other than the text your are editing or adding. No longer is the HTML output stripped of excess spaces and reformatted in IEs format. So if I do: private void button3_Click(object sender, RoutedEventArgs e) { dynamic doc = this.webBrowser.Document; doc.body.contentEditable = true; } and then make some changes to the document by typing into it using IE 9 mode, the document formatting stays intact and only the affected content is modified. The created HTML is reasonably clean (although it does lack proper XHTML formatting for things like <br/> <hr/>). This is very different from IE 7 mode which mangled the HTML as soon as the page was loaded into the control. Any editing you did stripped out all white space and lost all of your existing XHTML formatting. In IE 9 mode at least *most* of your original formatting stays intact. This is huge! In Html Help Builder I have supported HTML editing for a long time but the HTML mangling by the Web Browser control made it very difficult to edit the HTML later. Previously IE would mangle the HTML by stripping out spaces, upper casing all tags and converting many XHTML safe tags to its HTML 3 tags. Now IE leaves most of my document alone while editing, and creates cleaner and more compliant markup (with exception of self-closing elements like BR/HR). The end result is that I now have HTML editing in place that's much cleaner and actually capable of being manually edited. Caveats, Caveats, Caveats It wouldn't be Internet Explorer if there weren't some major compatibility issues involved in using this various browser version interaction. The biggest thing I ran into is that there are odd differences in some of the COM interfaces and what they return. I specifically ran into a problem with the document.selection.createRange() function which with IE 7 compatibility returns an expected text range object. When running in IE 8 or IE 9 mode however. I could not retrieve a valid text range with this code where loEdit is the WebBrowser control: loRange = loEdit.document.selection.CreateRange() The loRange object returned (here in FoxPro) had a length property of 0 but none of the other properties of the TextRange or TextRangeCollection objects were available. I figured this was due to some changed security settings but even after elevating the Intranet Security Zone and mucking with the other browser feature flags pertaining to security I had no luck. In the end I relented and used a JavaScript function in my editor document that returns a selection range object: function getselectionrange() { var range = document.selection.createRange(); return range; } and call that JavaScript function from my host applications code: *** Use a function in the document to get around HTML Editing issues loRange = loEdit.document.parentWindow.getselectionrange(.f.) and that does work correctly. This wasn't a big deal as I'm already loading a support script file into the editor page so all I had to do is add the function to this existing script file. You can find out more how to call script code in the Web Browser control from a host application in a previous post of mine. IE 8 and 9 also clamp down the security environment a little more than the default IE 7 control, so there may be other issues you run into. Other than the createRange() problem above I haven't seen anything else that is breaking in my code so far though and that's encouraging at least since it uses a lot of HTML document manipulation for the custom editor I've created (and would love to replace - any PROFESSIONAL alternatives anybody?) Registry Key Installation for your Application It’s important to remember that this registry setting is made per application, so most likely this is something you want to set up with your installer. Also remember that 32 and 64 bit settings require separate settings in the registry so if you’re creating your installer you most likely will want to set both keys in the registry preemptively for your application. I use Tarma Installer for all of my application installs and in Tarma I configure registry keys for both and set a flag to only install the latter key group in the 64 bit version: Because this setting is application specific you have to do this for every application you install unfortunately, but this also means that you can safely configure this setting in the registry because it is after only applied to your application. Another problem with install based installation is version detection. If IE 8 is installed I’d want 8000 for the value, if IE 9 is installed I want 9000. I can do this easily in code but in the installer this is much more difficult. I don’t have a good solution for this at the moment, but given that the app works with IE 7 mode now, IE 9 mode is just a bonus for the moment. If IE 9 is not installed and 9000 is used the default rendering will remain in use.   It sure would be nice if we could specify the IE rendering mode as a property, but I suspect the ActiveX container has to know before it loads what actual version to load up and once loaded can only load a single version of IE. This would account for this annoying application level configuration… Summary The registry feature emulation has been available for quite some time, but I just found out about it today and started experimenting around with it. I’m stoked to see that this is available as I’d pretty much given up in ever seeing any better rendering in the Web Browser control. Now at least my apps can take advantage of newer HTML features. Now if we could only get better HTML Editing support somehow <snicker>… ah can’t have everything.© Rick Strahl, West Wind Technologies, 2005-2011Posted in .NET  FoxPro  Windows  

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  • SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

    - by pinaldave
    This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

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  • Special thanks to everyone that helped me in 2010.

    - by mbcrump
    2010 has been a very good year for me and I wanted to create a list and thank everyone for what they have done for me.  I also wanted to thank everyone for reading and subscribing to my blog. It is hard to believe that people actually want to read what I write. I feel like I owe a huge thanks to everyone listed below. Looking back upon 2010, I feel that I’ve grown as a developer and you are part of that reason. Sometimes we get caught up in day to day work and forget to give thanks to those that helped us along the way. The list below is mine, it includes people and companies. This list is obviously not going to include everyone that has helped, just those that have stood out in my mind. When I think back upon 2010, their names keep popping up in my head. So here goes, in no particular order.  People Dave Campbell – For everything he has done for the Silverlight Community with his Silverlight Cream blog. I can’t think of a better person to get recognition at the Silverlight FireStarter event. I also wanted to thank him for spending several hours of his time helping me track down a bug in my feedburner account. Victor Gaudioso – For his large collection of video tutorials on his blog and the passion and enthusiasm he has for Silverlight. We have talked on the phone and I’ve never met anyone so fired up for Silverlight. Kunal Chowdhury – Kunal has always been available for me to bounce ideas off of. Kunal has also answered a lot of questions that stumped me. His blog and CodeProject article have green a great help to me and the Silverlight Community. Glen Gordon – I was looking frantically for a Windows Phone 7 several months before release and Glen found one for me. This allowed me to start a blog series on the Windows Phone 7 hardware and developing an application from start to finish that Scott Guthrie retweeted.  Jeff Blankenburg – For listening to my complaints in the early stages of Windows Phone 7. Jeff was always very polite and gave me his cell phone number to talk it over. He also walked me through several problems that I was having early on. Pete Brown – For writing Silverlight 4 in Action. This book is definitely a labor of love. I followed Pete on Twitter as he was writing it and he spent a lot of late nights and weekends working on it. I felt a lot smarter after reading it the first time. The second time was even better. John Papa – For all of his work on the Silverlight Firestarter and the Silverlight community in general. He has also helped me on a personal level with several things. Daniel Heisler – For putting up with me the past year while we worked on many .NET projects together in 2010. Alvin Ashcraft – For publishing a daily blog post on the best of .NET links. He has linked to my site many times and I really appreciate what he does for the community. Chris Alcock – For publishing the Morning Brew every weekday. I remember when I first appeared on his site, I started getting hundreds of hits on my site and wondered if I was getting a DOS attack or something. It was great to find out that Chris had linked to one of my articles. Joel Cochran – For spending a week teaching “Blend-O-Rama”. This was my one of my favorite sessions of this year. I learned a lot about Expression Blend from it and the best part was that it was free and during lunchtime. Jeremy Likness – Jeremy is smart – very smart. I have learned a lot from Jeremy over the past year. He is also involved in the Silverlight community in every way possible, from forums to blog post to screencast to open source. It goes on and on. The people that I met at VSLive Orlando 2010. I had a great time chatting with Walt Ritscher, Wallace McClure, Tim Huckabee and David Platt. Also a special thanks to all of my friends on Twitter like @wilhil, @DBVaughan, @DataArtist, @wbm, @DirkStrauss and @rsringeri and many many more. Software Companies / Events / May of gave me FREE stuff. =) Microsoft (3) – I was sent a free coupon code by Microsoft to take the Silverlight 4 Beta Exam. I jumped on the offer and took the exam. It was great being selected to try out the exam before it goes public even though Microsoft eventually published a universal coupon code for everyone. I am still waiting to find out if I passed the exam. My fingers are crossed. Microsoft reaching out to me with some questions regarding the .NET Community. I’ve never had a company contact me with such interest in the community. Having a contest where 75 people could win a $100 gift certificate and a T-Shirt for submitting a Windows Phone 7 app. I submitted my app and won. All of the free launch events this year (Windows Phone 7, Visual Studio 2010, ASP.NET MVC). Wintellect – For providing an awesome day of free technical training called T.E.N. Where else can you get free training from some of the best programmers in the world? I also won a contest from them that included a NETAdvantage Ultimate License from Infragistics. VSLive – I attended the Orlando 2010 Conference and it was the best developer’s conference that I have ever attended. I got to know a lot of people at this conference and hang out with many wonderful speakers. I live tweeted the event and while it may have annoyed some, the organizers of VSLive loved it. I won the contest on Twitter and they invited me back to the 2011 session of my choice. This is a very nice gift and I really appreciate the generosity. BarcodeLib.com – For providing free barcode generating tools for a Non-Profit ASP.NET project that I was working on. Their third party controls really made this a breeze compared to my existing solution. NDepend – It is absolutely the best tool to improve code quality. The product is extremely large and I would recommend heading over to their site to check it out. Silverlight Spy – I was writing a blog post on Silverlight Spy and Koen Zwikstra provided a FREE license to me. If you ever wanted to peek inside of a Silverlight Application then this is the tool for you. He is also working on a version that will support OOB and Windows Phone 7. I would recommend checking out his site. Birmingham .NET Users Group / Silverlight Nights User Group – It takes a lot of time to put together a user group meeting every month yet it always seems to happen. I don’t want to name names for fear of leaving someone out but both of these User Groups are excellent if you live in the Birmingham, Alabama area. Publishing Companies Manning Publishing – For giving me early access to Silverlight 4 in Action by Pete Brown. It was really nice to be able to read this awesome book while Pete was writing it. I was also one of the first people to publish a review of the book. Sams Publishing and DZone – For providing a copy of Silverlight 4 Unleashed by Laurent Bugnion for me to review for their site. The review is coming in January 2011. Special Shoutout to the following 3rd Party Silverlight Controls It has been a great pleasure to work with the following companies on 3rd Party Control Giveaways every month. It always amazes me how every 3rd Party Control company is so eager to help out the community. I’ve never been turned down by any of these companies! These giveaways have sparked a lot of interest in Silverlight and hopefully I can continue giving away a new set every month. If you are a 3rd Party Control company and are interested in participating in these giveaways then please email me at mbcrump29[at]gmail[d0t].com. The companies below have already participated in my giveaways: Infragistics (December 2010) - Win a set of Infragistics Silverlight Controls with Data Visualization!  Mindscape (November 2010) - Mindscape Silverlight Controls + Free Mega Pack Contest Telerik (October 2010) - Win Telerik RadControls for Silverlight! ($799 Value) Again, I just wanted to say Thanks to everyone for helping me grow as a developer.  Subscribe to my feed

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  • SQL SERVER – Weekly Series – Memory Lane – #003

    - by pinaldave
    Here is the list of curetted articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 This was the first year of my blogging and lots of new things I was learning as I go. I was indeed an infant in blogging a few years ago. However, as time passed by I have learned a lot. This year was year of experiments and new learning. 2007 Working as a full time DBA I often encoutered various errors and I started to learn how to avoid those error and document the same. ERROR Msg 5174 Each file size must be greater than or equal to 512 KB Whenever I see this error I wonder why someone is trying to attempt a database which is extremely small. Anyway, it does not matter what I think I keep on seeing this error often in industries. Anyway the solution of the error is equally interesting – just created larger database. Dilbert Humor This was very first encounter with database humor and I started to love it. It does not matter how many time we read this cartoon it does not get old. Generate Script with Data from Database – Database Publishing Wizard Generating schema script with data is one of the most frequently performed tasks among SQL Server Data Professionals. There are many ways to do the same. In the above article I demonstrated that how we can use the Database Publishing Wizard to accomplish the same. It was new to me at that time but I have not seen much of the adoption of the same still in the industry. Here is one of my videos where I demonstrate how we can generate data with schema. 2008 Delete Backup History – Cleanup Backup History Deleting backup history is important too but should be done carefully. If this is not carried out at regular interval there is good chance that MSDB will be filled up with all the old history. Every organization is different. Some would like to keep the history for 30 days and some for a year but there should be some limit. One should regularly archive the database backup history. South Asia MVP Open Days 2008 This was my very first year Microsoft MVP. I had Indeed big blast at the event and the fun was incredible. After this event I have attended many different MVP events but the fun and learning this particular event presented was amazing and just like me many others are not able to forget the same. Here are other links related to the event: South Asia MVP Open Day 2008 – Goa South Asia MVP Open Day 2008 – Goa – Day 1 South Asia MVP Open Day 2008 – Goa – Day 2 South Asia MVP Open Day 2008 – Goa – Day 3 2009 Enable or Disable Constraint  This is very simple script but I personally keep on forgetting it so I had blogged it. Till today, I keep on referencing this again and again as sometime a very little thing is hard to remember. Policy Based Management – Create, Evaluate and Fix Policies This article will cover the most spectacular feature of SQL 2008 – Policy-based management and how the configuration of SQL Server with policy-based management architecture can make a powerful difference. Policy based management is loaded with several advantages. It can help you implement various policies for reliable configuration of the system. It also provides additional administrative assistance to DBAs and helps them effortlessly manage various tasks of SQL Server across the enterprise. SQLPASS 2009 – My Very First SQPASS Experience Just Brilliant! I never had an experience such a thing in my life. SQL SQL and SQL – all around SQL! I am listing my own reasons here in order of importance to me. Networking with SQL fellows and experts Putting face to the name or avatar Learning and improving my SQL skills Understanding the structure of the largest SQL Server Professional Association Attending my favorite training sessions Since last time I have never missed a single time this event. This event is my favorite event and something keeps me going. Here are additional post related SQLPASS 2009. SQL PASS Summit, Seattle 2009 – Day 1 SQL PASS Summit, Seattle 2009 – Day 2 SQL PASS Summit, Seattle 2009 – Day 3 SQL PASS Summit, Seattle 2009 – Day 4 2010 Get All the Information of Database using sys.databases Even though we believe that we know everything about our database, we do not know a lot of things about our database. This little script enables us to know so many details about databases which we may not be familiar with. Run this on your server today and see how much you know your database. Reducing CXPACKET Wait Stats for High Transactional Database While engaging in a performance tuning consultation for a client, a situation occurred where they were facing a lot of CXPACKET Waits Stats. The client asked me if I could help them reduce this huge number of wait stats. I usually receive this kind of request from other client as well, but the important thing to understand is whether this question has any merits or benefits, or not. I discusses the same in this article – a bit long but insightful for sure. Error related to Database in Use There are so many database management operations in SQL Server which requires exclusive access to the database and it is not always possible to get it. When any database is online in SQL Server it either applications or system thread often accesses them. This means database can’t have exclusive access and the operations which required this access throws an error. There is very easy method to overcome this minor issue – a single line script can give you exclusive access to the database. Difference between DATETIME and DATETIME2 Developers have found the root reason of the problem when dealing with Date Functions – when data time values are converted (implicit or explicit) between different data types, which would lose some precision, so the result cannot match each other as expected. In this blog post I go over very interesting details and difference between DATETIME and DATETIME2 History of SQL Server Database Encryption I recently met Michael Coles and Rodeney Landrum the author of one of the kind book Expert SQL Server 2008 Encryption at SQLPASS in Seattle. During the conversation we ended up how Microsoft is evolving encryption technology. The same discussion lead to talking about history of encryption tools in SQL Server. Michale pointed me to page 18 of his book of encryption. He explicitly gave me permission to re-produce relevant part of history from his book. 2011 Functions FIRST_VALUE and LAST_VALUE with OVER clause and ORDER BY Some time an interesting feature and smart audience make a total difference in places. From last two days, I have been writing on SQL Server 2012 feature FIRST_VALUE and LAST_VALUE. I created a puzzle which was very interesting and got many people attempt to resolve it. It was based on following two articles: Introduction to FIRST_VALUE and LAST_VALUE Introduction to FIRST_VALUE and LAST_VALUE with OVER clause I even provided the hint about how one can solve this problem. The best part was many people solved the problem without using hints! Try your luck!  A Real Story of Book Getting ‘Out of Stock’ to A 25% Discount Story Available This is a great problem and everybody would love to have it. We had it and we loved it. Our book got out of stock in 48 hours of releasing and stocks were empty. We faced many issues and learned many valuable lessons. Some we were able to avoid in the future and some we are still facing it as those problems have no solutions. However, since that day – our books never gone out of stock. This inspiring learning story for us and I am confident that you will love to read it as well. Introduction to LEAD and LAG – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function LEAD() and LAG(). This function accesses data from a subsequent row (for lead) and previous row (for lag) in the same result set without the use of a self-join . It will be very difficult to explain this in words so I will attempt small example to explain you this function. I had a fantastic time writing this blog post and I am very confident when you read it, you will like the same. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Calling the same xsl:template for different node names of the same complex type

    - by CraftyFella
    Hi, I'm trying to keep my xsl DRY and as a result I wanted to call the same template for 2 sections of an XML document which happen to be the same complex type (ContactDetails and AltContactDetails). Given the following XML: <?xml version="1.0" encoding="UTF-8"?> <RootNode> <Name>Bob</Name> <ContactDetails> <Address> <Line1>1 High Street</Line1> <Town>TownName</Town> <Postcode>AB1 1CD</Postcode> </Address> <Email>[email protected]</Email> </ContactDetails> <AltContactDetails> <Address> <Line1>3 Market Square</Line1> <Town>TownName</Town> <Postcode>EF2 2GH</Postcode> </Address> <Email>[email protected]</Email> </AltContactDetails> </RootNode> I wrote an XSL Stylesheet as follows: <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:template match="/"> <PersonsName> <xsl:value-of select="RootNode/Name"/> </PersonsName> <xsl:call-template name="ContactDetails"> <xsl:with-param name="data"><xsl:value-of select="RootNode/ContactDetails"/></xsl:with-param> <xsl:with-param name="elementName"><xsl:value-of select="'FirstAddress'"/></xsl:with-param> </xsl:call-template> <xsl:call-template name="ContactDetails"> <xsl:with-param name="data"><xsl:value-of select="RootNode/AltContactDetails"/></xsl:with-param> <xsl:with-param name="elementName"><xsl:value-of select="'SecondAddress'"/></xsl:with-param> </xsl:call-template> </xsl:template> <xsl:template name="ContactDetails"> <xsl:param name="data"></xsl:param> <xsl:param name="elementName"></xsl:param> <xsl:element name="{$elementName}"> <FirstLine> <xsl:value-of select="$data/Address/Line1"/> </FirstLine> <Town> <xsl:value-of select="$data/Address/Town"/> </Town> <PostalCode> <xsl:value-of select="$data/Address/Postcode"/> </PostalCode> </xsl:element> </xsl:template> </xsl:stylesheet> When i try to run the style sheet it's complaining to me that I need to: To use a result tree fragment in a path expression, either use exsl:node-set() or specify version 1.1 I don't want to go to version 1.1.. So does anyone know how to get the exsl:node-set() working for the above example? Or if someone knows of a better way to apply the same template to 2 different sections then that would also really help me out? Thanks Dave

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  • ASP.NET MVC 2 Model encapsulated within ViewModel Validation

    - by Program.X
    I am trying to get validation to work in ASP.NET MVC 2, but without much success. I have a complex class containing a large number of fields. (Don't ask - this is oneo f those real-world situations best practices can't touch) This would normally be my Model and is a LINQ-to-SQL generated class. Because this is generated code, I have created a MetaData class as per http://davidhayden.com/blog/dave/archive/2009/08/10/AspNetMvc20BuddyClassesMetadataType.aspx. public class ConsultantRegistrationMetadata { [DisplayName("Title")] [Required(ErrorMessage = "Title is required")] [StringLength(10, ErrorMessage = "Title cannot contain more than 10 characters")] string Title { get; set; } [Required(ErrorMessage = "Forename(s) is required")] [StringLength(128, ErrorMessage = "Forename(s) cannot contain more than 128 characters")] [DisplayName("Forename(s)")] string Forenames { get; set; } // ... I've attached this to the partial class of my generated class: [MetadataType(typeof(ConsultantRegistrationMetadata))] public partial class ConsultantRegistration { // ... Because my form is complex, it has a number of dependencies, such as SelectLists, etc. which I have encapsulated in a ViewModel pattern - and included the ConsultantRegistration model as a property: public class ConsultantRegistrationFormViewModel { public Data.ConsultantRegistration ConsultantRegistration { get; private set; } public SelectList Titles { get; private set; } public SelectList Countries { get; private set; } // ... So it is essentially ViewModel=Model My View then has: <p> <%: Html.LabelFor(model => model.ConsultantRegistration.Title) %> <%: Html.DropDownListFor(model => model.ConsultantRegistration.Title, Model.Titles,"(select a Title)") %> <%: Html.ValidationMessage("Title","*") %> </p> <p> <%: Html.LabelFor(model => model.ConsultantRegistration.Forenames) %> <%: Html.TextBoxFor(model => model.ConsultantRegistration.Forenames) %> <%: Html.ValidationMessageFor(model=>model.ConsultantRegistration.Forenames) %> </p> The problem is, the validation attributes on the metadata class are having no effect. I tried doing it via an Interface, but also no effect. I'm beginning to think that the reason is because I am encapsulating my model within a ViewModel. My Controller (Create Action) is as follows: [HttpPost] public ActionResult Create(Data.ConsultantRegistration consultantRegistration) { if (ModelState.IsValid) // this is always true - which is wrong!! { try { consultantRegistration = ConsultantRegistrationRepository.SaveConsultantRegistration(consultantRegistration); return RedirectToAction("Edit", new { id = consultantRegistration.ID, sectionIndex = 2 }); } catch (Exception ex) { ModelState.AddModelError("CreateException",ex); } } return View(new ConsultantRegistrationFormViewModel(consultantRegistration)); } As outlined in the comment, the ModelState.IsValid property always returns true, despite fields with the Validaiton annotations not being valid. (Forenames being a key example). Am I missing something obvious - considering I am an MVC newbie? I'm after the mechanism demoed by Jon Galloway at http://www.asp.net/learn/mvc-videos/video-10082.aspx. (Am aware t is similar to http://stackoverflow.com/questions/1260562/asp-net-mvc-model-viewmodel-validation but that post seems to talk about xVal. I have no idea what that is and suspect it is for MVC 1)

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  • xsl:include template with no default namespace causes xmlns=""

    - by CraftyFella
    Hi, I've got a problem with xsl:include and default namespaces which is causing the final xml document contain nodes with the xmlns="" In this synario I have 1 source document which is Plain Old XML and doesn't have a namespace: <?xml version="1.0" encoding="UTF-8"?> <SourceDoc> <Description>Hello I'm the source description</Description> <Description>Hello I'm the source description 2</Description> <Description/> <Title>Hello I'm the title</Title> </SourceDoc> This document is transformed into 2 different xml documents each with their own default namespace. First Document: <?xml version="1.0" encoding="utf-8"?> <OutputDocType1 xmlns="http://MadeupNS1"> <Description >Hello I'm the source description</Description> <Description>Hello I'm the source description 2</Description> <Title>Hello I'm the title</Title> </OutputDocType1> Second Document: <?xml version="1.0" encoding="utf-8"?> <OutputDocType2 xmlns="http://MadeupNS2"> <Description>Hello I'm the source description</Description> <Description>Hello I'm the source description 2</Description> <DocTitle>Hello I'm the title</DocTitle> </OutputDocType2> I want to be able to re-use the template for descriptions in both of the transforms. As it's the same logic for both types of document. To do this I created a template file which was *xsl:include*d in the other 2 transformations: <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output indent="yes" method="xml"/> <xsl:template match="Description[. != '']"> <Description> <xsl:value-of select="."/> </Description> </xsl:template> </xsl:stylesheet> Now the problem here is that this shared transformation can't have a default Namespace as it will be different depending on which of the calling transformations calls it. E.g. for First Document Transformation: <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output indent="yes" method="xml"/> <xsl:template match="SourceDoc"> <OutputDocType1 xmlns="http://MadeupNS1"> <xsl:apply-templates select="Description"/> <xsl:if test="Title"> <Title> <xsl:value-of select="Title"/> </Title> </xsl:if> </OutputDocType1> </xsl:template> <xsl:include href="Template.xsl"/> </xsl:stylesheet> This actually outputs it as follows: <?xml version="1.0" encoding="utf-8"?> <OutputDocType1 xmlns="http://MadeupNS1"> <Description xmlns="">Hello I'm the source description</Description> <Description xmlns="">Hello I'm the source description 2</Description> <Title>Hello I'm the title</Title> </OutputDocType1> Here is the problem. On the description Lines I get an xmlns="" Does anyone know how to solve this issue? Thanks Dave

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  • SQL SERVER – Weekly Series – Memory Lane – #007

    - by pinaldave
    Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 Find Stored Procedure Related to Table in Database – Search in All Stored Procedure In 2006 I wrote a small script which will help user  find all the Stored Procedures (SP) which are related to one or more specific tables. This was quite a popular script however, in SQL Server 2012 the same can be achieved using new DMV sys.sql-expression_dependencies. I recently blogged about it over Find Referenced or Referencing Object in SQL Server using sys.sql_expression_dependencies. 2007 SQL SERVER – Versions, CodeNames, Year of Release 1993 – SQL Server 4.21 for Windows NT 1995 – SQL Server 6.0, codenamed SQL95 1996 – SQL Server 6.5, codenamed Hydra 1999 – SQL Server 7.0, codenamed Sphinx 1999 – SQL Server 7.0 OLAP, codenamed Plato 2000 – SQL Server 2000 32-bit, codenamed Shiloh (version 8.0) 2003 – SQL Server 2000 64-bit, codenamed Liberty 2005 – SQL Server 2005, codenamed Yukon (version 9.0) 2008 – SQL Server 2008, codenamed Katmai (version 10.0) 2011 – SQL Server 2008, codenamed Denali (version 11.0) Search String in Stored Procedure Searching sting in the stored procedure is one of the most frequent task developer do. They might be searching for a table, view or any other details. I have written a script to do the same in SQL Server 2000 and SQL Server 2005. This is worth bookmarking blog post. There is an alternative way to do the same as well here is the example. 2008 SQL SERVER – Refresh Database Using T-SQL NO! Some of the questions have a single answer NO! You may want to read the question in the original blog post. I had a great time saying No! SQL SERVER – Delete Backup History – Cleanup Backup History SQL Server stores history of all the taken backup forever. History of all the backup is stored in the msdb database. Many times older history is no more required. Following Stored Procedure can be executed with a parameter which takes days of history to keep. In the following example 30 is passed to keep a history of month. 2009 Stored Procedure are Compiled on First Run – SP taking Longer to Run First Time Is stored procedure pre-compiled? Why the Stored Procedure takes a long time to run for the first time?  This is a very common questions often discussed by developers and DBAs. There is an absolutely definite answer but the question has been discussed forever. There is a misconception that stored procedures are pre-compiled. They are not pre-compiled, but compiled only during the first run. For every subsequent runs, it is for sure pre-compiled. Read the entire article for example and demonstration. Removing Key Lookup – Seek Predicate – Predicate – An Interesting Observation Related to Datatypes This is one of the most important performance tuning lesson on my blog. I suggest this weekend you spend time reading them and let me know what you think about the concepts which I have demonstrated in the four part series. Part 1 | Part 2 | Part 3 | Part 4 Seek Predicate is the operation that describes the b-tree portion of the Seek. Predicate is the operation that describes the additional filter using non-key columns. Based on the description, it is very clear that Seek Predicate is better than Predicate as it searches indexes whereas in Predicate, the search is on non-key columns – which implies that the search is on the data in page files itself. Policy Based Management – Create, Evaluate and Fix Policies This article will cover the most spectacular feature of SQL Server – Policy-based management and how the configuration of SQL Server with policy-based management architecture can make a powerful difference. Policy based management is loaded with several advantages. It can help you implement various policies for reliable configuration of the system. It also provides additional administration assistance to DBAs and helps them effortlessly manage various tasks of SQL Server across the enterprise. 2010 Recycle Error Log – Create New Log file without Server Restart Once I observed a DBA to restaring the SQL Server when he needed new error log file. This was funny and sad both at the same time. There is no need to restart the server to create a new log file or recycle the log file. You can run sp_cycle_errorlog and achieve the same result. Get Database Backup History for a Single Database Simple but effective script! Reducing CXPACKET Wait Stats for High Transactional Database The subject is very complex and I have done my best to simplify the concept. In simpler words, when a parallel operation is created for SQL Query, there are multiple threads for a single query. Each query deals with a different set of the data (or rows). Due to some reasons, one or more of the threads lag behind, creating the CXPACKET Wait Stat. Threads which came first have to wait for the slower thread to finish. The Wait by a specific completed thread is called CXPACKET Wait Stat. Information Related to DATETIME and DATETIME2 There are quite a lot of confusion with DATETIME and DATETIME2. DATETIME2 is also one of the underutilized datatype of SQL Server.  In this blog post I have written a follow up of the my earlier datetime series where I clarify a few of the concepts related to datetime. Difference Between GETDATE and SYSDATETIME Difference Between DATETIME and DATETIME2 – WITH GETDATE Difference Between DATETIME and DATETIME2 2011 Introduction to CUME_DIST – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function CUME_DIST(). This function provides cumulative distribution value. It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. Introduction to FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical functions FIRST_VALUE() and LAST_VALUE(). This function returns first and last value from the list. It will be very difficult to explain this in words so I’d like to attempt to explain its function through a brief example. Instead of creating a new table, I will be using the AdventureWorks sample database as most developers use that for experiment purposes. OVER clause with FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 – ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING “Don’t you think there is bug in your first example where FIRST_VALUE is remain same but the LAST_VALUE is changing every line. I think the LAST_VALUE should be the highest value in the windows or set of result.” Puzzle – Functions FIRST_VALUE and LAST_VALUE with OVER clause and ORDER BY You can see that row number 2, 3, 4, and 5 has same SalesOrderID = 43667. The FIRST_VALUE is 78 and LAST_VALUE is 77. Now if these function was working on maximum and minimum value they should have given answer as 77 and 80 respectively instead of 78 and 77. Also the value of FIRST_VALUE is greater than LAST_VALUE 77. Why? Explain in detail. Introduction to LEAD and LAG – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function LEAD() and LAG(). This functions accesses data from a subsequent row (for lead) and previous row (for lag) in the same result set without the use of a self-join . It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. A Real Story of Book Getting ‘Out of Stock’ to A 25% Discount Story Available Our book was out of stock in 48 hours of it was arrived in stock! We got call from the online store with a request for more copies within 12 hours. But we had printed only as many as we had sent them. There were no extra copies. We finally talked to the printer to get more copies. However, due to festivals and holidays the copies could not be shipped to the online retailer for two days. We knew for sure that they were going to be out of the book for 48 hours. This is the story of how we overcame that situation! Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • How to copy this portion of a text file out and put into a hash using rails? (VATsim datafile)

    - by Rusty Broderick
    Hi I'm trying to work out how i can cut out the section between !CLIENTS and the '; ;' and then to parse it into a hash in order to make an xml file. Honestly have no idea how to do it. The file is as follows: vatsim-data.txt original file here ; Created at 30/12/2010 01:29:14 UTC by Data Server V4.0 ; ; Data is the property of VATSIM.net and is not to be used for commercial purposes without the express written permission of the VATSIM.net Founders or their designated agent(s ). ; ; Sections are: ; !GENERAL contains general settings ; !CLIENTS contains informations about all connected clients ; !PREFILE contains informations about all prefiled flight plans ; !SERVERS contains a list of all FSD running servers to which clients can connect ; !VOICE SERVERS contains a list of all running voice servers that clients can use ; ; Data formats of various sections are: ; !GENERAL section - VERSION is this data format version ; RELOAD is time in minutes this file will be updated ; UPDATE is the last date and time this file has been updated. Format is yyyymmddhhnnss ; ATIS ALLOW MIN is time in minutes to wait before allowing manual Atis refresh by way of web page interface ; CONNECTED CLIENTS is the number of clients currently connected ; !CLIENTS section - callsign:cid:realname:clienttype:frequency:latitude:longitude:altitude:groundspeed:planned_aircraft:planned_tascruise:planned_depairport:planned_altitude:planned_destairport:server:protrevision:rating:transponder:facilitytype:visualrange:planned_revision:planned_flighttype:planned_deptime:planned_actdeptime:planned_hrsenroute:planned_minenroute:planned_hrsfuel:planned_minfuel:planned_altairport:planned_remarks:planned_route:planned_depairport_lat:planned_depairport_lon:planned_destairport_lat:planned_destairport_lon:atis_message:time_last_atis_received:time_logon:heading:QNH_iHg:QNH_Mb: ; !PREFILE section - callsign:cid:realname:clienttype:frequency:latitude:longitude:altitude:groundspeed:planned_aircraft:planned_tascruise:planned_depairport:planned_altitude:planned_destairport:server:protrevision:rating:transponder:facilitytype:visualrange:planned_revision:planned_flighttype:planned_deptime:planned_actdeptime:planned_hrsenroute:planned_minenroute:planned_hrsfuel:planned_minfuel:planned_altairport:planned_remarks:planned_route:planned_depairport_lat:planned_depairport_lon:planned_destairport_lat:planned_destairport_lon:atis_message:time_last_atis_received:time_logon:heading:QNH_iHg:QNH_Mb: ; !SERVERS section - ident:hostname_or_IP:location:name:clients_connection_allowed: ; !VOICE SERVERS section - hostname_or_IP:location:name:clients_connection_allowed:type_of_voice_server: ; ; Field separator is : character ; ; !GENERAL: VERSION = 8 RELOAD = 2 UPDATE = 20101230012914 ATIS ALLOW MIN = 5 CONNECTED CLIENTS = 515 ; ; !VOICE SERVERS: voice2.vacc-sag.org:Nurnberg:Europe-CW:1:R: voice.vatsim.fi:Finland - Sponsored by Verkkokauppa.com and NBL Solutions:Finland:1:R: rw.liveatc.net:USA, California:Liveatc:1:R: rw1.vatpac.org:Melbourne, Australia:Oceania:1:R: spain.vatsim.net:Spain:Vatsim Spain Server:1:R: voice.nyartcc.org:Sponsored by NY ARTCC:NY-ARTCC:1:R: voice.zhuartcc.net:Sponsored by Houston ARTCC:ZHU-ARTCC:1:R: ; ; !CLIENTS: 01PD:1090811:prentis gibbs KJFK:PILOT::40.64841:-73.81030:15:0::0::::USA-E:100:1:1200::::::::::::::::::::20101230010851:28:30.1:1019: 4X-BRH:1074589:george sandoval LLJR:PILOT::50.05618:-125.84429:10819:206:C337/G:150:CYAL:FL120:CCI9:EUROPE-C2:100:1:6043:::2:I:110:110:1:26:2:59:: /T/:DCT:0:0:0:0:::20101230005323:129:29.76:1007: 50125:1109107:Dave Frew KEDU:PILOT::46.52736:-121.95317:23877:471:B/B744/F:530:KTCM:30000:KLSV:USA-E:100:1:7723:::1:I:0:116:0:0:0:0:::GPS DIRECT.:0:0:0:0:::20101230012346:164:29.769:1008: 85013:1126003:Dmitry Abramov UWWW:PILOT::76.53819:71.54782:33444:423:T/ZZZZ/G:500:UUDD:FL330:ULAA:EUROPE-C2:100:1:2200:::2:I:0:2139:0:0:0:0:ULLI::BITSA DCT WM/N0485S1010 DCT KS DCT NE R22 ULWW B153 LAPEK B210 SU G476 OLATA:0:0:0:0:::20101229215815:62:53.264:1803: ; ; !SERVERS: EUROPE-C2:88.198.19.202:Europe:Center Europe Server Two:1: ; ; END I want to format the html with the tags with client being the parent and the nested tags as follows: callsign:cid:realname:clienttype:frequency:latitude:longitude:altitude:groundspeed:planned_aircraft:planned_tascruise:planned_depairport:planned_altitude:planned_destairport:server:protrevision:rating:transponder:facilitytype:visualrange:planned_revision:planned_flighttype:planned_deptime:planned_actdeptime:planned_hrsenroute:planned_minenroute:planned_hrsfuel:planned_minfuel:planned_altairport:planned_remarks:planned_route:planned_depairport_lat:planned_depairport_lon:planned_destairport_lat:planned_destairport_lon:atis_message:time_last_atis_received:time_logon:heading:QNH_iHg:QNH_Mb: Any help in solving this would be much appreciated!

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