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  1. #1
    Join Date
    Nov 2007

    Unanswered: different execution time

    i have a different kind of issue.
    when a developer is running a select query(data warehouse complex query) using WIN SQL its taking more time(7min) and when the same query when executed by a DBA using db2batch or WIN SQL it takes less time(2min).
    this is happening may times when we tested the query. and also we executed almost at the same time one after the other(developer and DBA).both fetched the same results.even if the DBA run first and the developer runs second it is taking more time for the developer.since it might be in the bufferpool it should fetch the result little fast for the person who executes second.but thats not happening with developer.but for the DBA its fetching the result fast when executed second time.(result comming from bufferpool).

    what could be the possible reason?..and where to look at to find the possible reason for the issue?

  2. #2
    Join Date
    Jan 2007
    Jena, Germany
    Is the DBA executing the query directly at the database server and the developer from a client machine? How big is the result size? I'm asking because one reason could be that a big result is to be retrieved, and the network connection makes up for the time difference.

    Another issue could be that developer and DBA have different privileges on various objects (e.g. USE privs on table spaces).

    Also, have you verified that both, developer and DBA, get the same access plan for the query?
    Knut Stolze
    IBM DB2 Analytics Accelerator
    IBM Germany Research & Development

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