![]() ![]() To get to the heart of the deadlock, this is what you want (courtesy of this SO question/answer): Which is not particularly useful (but good to know, so you can see the blocked count). The following T-SQL will show you the “victim” processes, much like activity monitor does: select * from sys.sysprocesses where blocked > 0 This can be a serious condition, not just for SQL Server as processes become suspended, but for the applications which rely on SQL Server as well.Ī fast way to respond is to execute a bit of T-SQL on SQL Server, making use of System Views. The Database Engine chooses one of the sessions as a deadlock victim and the current transaction is terminated with an error to break the deadlock.īasically, it’s a resource contention issue which blocks one process or transaction from performing actions on resources within SQL Server. ![]() The SQL Server Database Engine automatically detects deadlock cycles within SQL Server. Task T2 has a lock on resource R2 (indicated by the arrow from R2 to T2) and has requested a lock on resource R1 (indicated by the arrow from T2 to R1).īecause neither task can continue until a resource is available and neither resource can be released until a task continues, a deadlock state exists. Task T1 has a lock on resource R1 (indicated by the arrow from R1 to T1) and has requested a lock on resource R2 (indicated by the arrow from T1 to R2). The following graph presents a high level view of a deadlock state where: Just let me know.īefore we get into diagnosis and investigation, it’s a good time to pose the question: “what is a deadlock?”:Ī deadlock occurs when two or more tasks permanently block each other by each task having a lock on a resource which the other tasks are trying to lock. If there’s a lot of interest in exploring SQL Server and deadlocks further, I’m happy to write an extended article going into far more detail. Recently I was asked about diagnosing deadlocks in SQL Server – I’ve done a lot of work in this area way back in 2008, so I figure it’s time for a refresher. ![]()
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