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Processes blocked by themselves

  • June 2, 2005 at 1:05 pm

    #89380

    Hi everyone,

    I see that my processes are blocking themselves...but they run and finish what they are doing also. For example, when I do an sp_who2, I see that process 60 (with no sub-processes) is blocking itself. What is going on?

  • June 2, 2005 at 2:42 pm

    #562727

    I don't know your environment and haven't seen this before.  But here are my two cents.  If you run, check SYSPROCESSES for spid 60, do you see multiple rows returned.  If yes, then it probably means that you have multiple processors (CPUs) and the threads could be blocking each other.  Whatever the query is that is running, if you change the DOP (Degree of Parallelism), you may see better results without the blocking.

    Read OPTION (MAXDOP 1) in BOL.  I don't have enough information to go on.  But it is probably what I would check first.

     

    Thanks

    Greg

  • June 3, 2005 at 2:40 am

    #562805

    I have experienced this - where a procedure ran fine on a single processor development server but slowed to a crawl on a multiprocessor production server. Restricting it to a single processor fixed the problem (although the solution adopted was to change the procedure so as to get a different execution plan).

  • September 7, 2005 at 10:30 am

    #588158

    Checked out SP4, i have seen an article saying that SP3 (yes SP3) isn't ALL hyper-threaded up.

    Just in the process of testing this and will let y'all know how it goes...

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