High CXPACKET on a single CPU database instance

  • Hi,

    Why would I see high CXPACKET waits on a database instance with only one CPU? Since the server only has 1 CPU parallelism can't be used, or are I'm missing something here!?

    SQL version

    Microsoft SQL Server 2012 - 11.0.5058.0 (X64)

    May 14 2014 18:34:29

    Copyright (c) Microsoft Corporation

    Standard Edition (64-bit) on Windows NT 6.3 <X64> (Build 9600: ) (Hypervisor)

    max degree of parallelism is set to 0

    Regards

    Michael

  • Unless you have a really, really, really old machine there (as in well over 10 years old) or a VM that a single virtual core has been assigned to, you've got a machine with a hyperthreaded, multi-core processor in it, hence queries can and will run in parallel.

    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
  • Are you 100% sure that you have 1 core presented?

  • tnx for the swift reply! It's a new virtual machine with one core presented, so I guess I know the answer now 😀

  • Just curious,

    Does the DB access to a CLR stored procedures or has any network latency issues?

  • Go to task manager, Click Performance, whatever no. of boxes you have under 'CPU Usages History' you have that many logical CPUs to run parallel queries.

    Isn't that right GilaMonster?

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