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Deadlocked schedulers dumps

  • January 16, 2015 at 1:44 am

    #300405

    Hello

    Recently a bunch of SQL Server 2008 R2 servers started to get Deadlocked schedulers errors.

    Environments are quite different. From 2 CPU Virtual servers with 10 GB of RAM to 16 CPU HP servers with 64 GB

    OS is Windows Server 2008 R2 (Standard and Enterprise)

    Tried to analyze Minidump file with a sqlwiki described article, but all specified possible issues are not visible in the dumps.

    After update to SP3 servers are not dumping anymore, but become unresponsive for some time with entries in SQL Error log

    New queries assigned to process on Node 0 have not been picked up by a worker thread in the last XXX seconds

    maybe there is some known issues I was not able to find?

    Thanks you

    Olegas

  • January 16, 2015 at 4:57 am

    #1770702

    That's an indication of long term blocking. It sounds like you need to tune your system or tune your queries. Deadlocks are also an indication of performance issues caused by long lock times. I would start capturing performance metrics and wait statistics on the servers to understand why things are running slow and which things are running slow.

    "The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
    - Theodore Roosevelt

    Author of:
    SQL Server Execution Plans
    SQL Server Query Performance Tuning

  • January 16, 2015 at 6:26 am

    #1770734

    To be honest, I'd call MS customer support. Scheduler deadlocks and related problems are fairly hard to debug and may involve reading stack dumps, they have the tools for this kind of thing. They're problems quite deep in the SQLOS.

    Few things first:

    Are you using custom extended procedures?

    Do you have high IO-related waits? If so, are all servers using the same storage?

    Do you have lots (10+) mirrored databases?

    Is this 32-bit or 64-bit?

    Can you zip and attach one of the text dumps? (not the .mdmp, there should be a text file as well with the human-readable stack dump info)

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass

  • January 17, 2015 at 3:03 am

    #1770943

    Hello

    Attached.

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