SQL query running slow after upgrading from 2005 to SQL 2012

  • yes, we tried maxdop but didn't help thanks

  • did you try to set the database compatibility level to 90?

  • Its a serial plan caused by Scalar function and is impossible to parallelise with the current versions of SQLServer up to 2016.

    This used to be the reason why partitioning with SQL2005 was a bad idea.

    Though I think that partitioning will still currently only allow one thread per partition since it is built on top of a Partition Scalar Function.

    In summary, Scalar functions are the devil.

    Catch-all queries done right [/url]
    Gail Shaw's Performance Blog[/url]

  • yes, one partition by one partition.

  • or can you just make a query plan and attach it to your query?

  • or maybe you defined some indexed view on your old 2005 instance, I do't think sql 2012 have that much memory difference to run a query, the most important thing is your should first make sure your have same query environment except sql versioin and memory.

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