#Would sql deadlock cause job to hang code#

So you'd get 2+ stacktraces, and all the information necessary to fix the problem. In dotnet 1.1, in a deadlock situation as described, as luck would have it all the threads which were locked would throw the exception at the same time. Walk up the stacktrace (preferably debug build with line numbers) and you'll immediately see what locks were held at the point of failure, and which one it was attempting to get.

My local version also immediately logs the stacktrace. If a deadlock is ever detected (lock unable to be obtained within the specified timeout, defaults to 10 seconds), then an exception is thrown.

#Would sql deadlock cause job to hang code#

But the TimedLock class has been of great help in finding deadlocks that exist in code without massive rework.īasically, (in dotnet/c#) you search/replace all your 'lock(xxx)' statements with 'using TimedLock.Lock(xxx)' No deadlock patterns to my knowledge (and 12 years of writing heavily multithreaded trading applications). He goes on to explain that the way to avoid deadlocks is to avoid (or thwart) condition four. This means that there is a cycle of threads, each of which is waiting for the next to release a resource before it can continue. In C#, this means that one thread can't force another thread to release a lock.Ī circular wait condition. In C#, this is akin to locking on one object and then locking on another before releasing the first lock, for example: The ability to hold one resource and request another. In the case of a monitor in C# (what you use when you employ the lock keyword), this limited number is one, since a monitor is a mutual-exclusion lock (meaning only one thread can own a monitor at a time). Stephen Toub in the MSDN article Deadlock monitor states the following four conditions necessary for deadlocks to occur:Ī limited number of a particular resource. In this scenario, you may experience a deadlock condition.Update: This recent MSDN article, Tools And Techniques to Identify Concurrency Issues, might also be of interest You call the SSIS package again or schedule a second SSIS package to start at the same time by using the _execution stored procedure.You schedule a Microsoft SQL Server Integration Services (SSIS) package to start by using the _execution stored procedure.The following information is a direct copy from Microsoft Support Document 2699720 Essentially that is what happens when you schedule two SSIS packages at the same exact time in SQL 2012, the procedure is run for each job that starts and causes the deadlock error seen above. If multiple calls are made with that stored procedure at the same time then a deadlock could occur. The reasoning behind this failure is the stored procedure in the SSISDB catalog.create_execution. Net SqlClient Data Provider Started: 1:00:01 AM Finished: 1:00:09 AM Elapsed: 8.331 seconds. The statement needs to find rows WHERE Username P1 AND UserDate P2, so you should have an index keyed on these columns. The answer is to provide an efficient access path for the DELETE. Description: Transaction () was deadlocked on lock resources with another process and has been chosen as the deadlock victim. That said, you shouldnt really care much about why the deadlock occurs, the important question is how do you avoid it. Server:, Package path: SSISDB.dtsx, Environment reference Id: NULL.

Started: 1:00:01 AM Failed to execute IS server package because of error 0x80131904. 60 for 32-bit Copyright (C) Microsoft Corporation. Microsoft (R) SQL Server Execute Package Utility Version. As you can see, the error only happened a couple of times even though all the 1:00 AM runs were at the same time as the other job.Įxecuted as user. There was no history of a failure in the SSIS execution logs, just the job failure. This seems a bit strange given that it was a deadlock on the step executing the SSIS package, not an error message from within the package. I recently had an interesting situation where an SSIS package was scheduled to run at 1 AM but failed with a deadlock message.