Redundant Indexes

  • TheSQLGuru (2/17/2011)


    1) That's an interesting script for dupe index checking Jason. Haven't seen one like that before. I need to give it a try.

    2) Duplicate indexes can indeed cause SIGNIFICANT issues with concurrency and DML response time. I had one client contact me after their system became almost unresponsive due to someone going hog-wild with DTA combined with a major data addition to the database. It took me a LONG to completely clean up that mess, but we eventually got to a great balance of fast SELECT performance AND fast/concurrent DML activity. Come to think of it, I have had to clean up quite a few DTA SNAFUs.

    Thanks, I found two different scripts which I adapted for my use from online somewhere. I was re-examining it and thinking it should also be updated to use the SQL 2005+ DMOs instead of the backward compatible views.

    As for DTA and hypothetical indexes, I have a script for that too. That script will script out the create statements for those hypothetical indexes and store that in a table and then drop the hypo indexes. It has been quite handy.

    Jason...AKA CirqueDeSQLeil
    _______________________________________________
    I have given a name to my pain...MCM SQL Server, MVP
    SQL RNNR
    Posting Performance Based Questions - Gail Shaw[/url]
    Learn Extended Events

  • CirquedeSQLeil (2/17/2011)


    TheSQLGuru (2/17/2011)


    1) That's an interesting script for dupe index checking Jason. Haven't seen one like that before. I need to give it a try.

    2) Duplicate indexes can indeed cause SIGNIFICANT issues with concurrency and DML response time. I had one client contact me after their system became almost unresponsive due to someone going hog-wild with DTA combined with a major data addition to the database. It took me a LONG to completely clean up that mess, but we eventually got to a great balance of fast SELECT performance AND fast/concurrent DML activity. Come to think of it, I have had to clean up quite a few DTA SNAFUs.

    Thanks, I found two different scripts which I adapted for my use from online somewhere. I was re-examining it and thinking it should also be updated to use the SQL 2005+ DMOs instead of the backward compatible views.

    As for DTA and hypothetical indexes, I have a script for that too. That script will script out the create statements for those hypothetical indexes and store that in a table and then drop the hypo indexes. It has been quite handy.

    Let me add my thanks - added your script to my sandbox DB and sure would like to encourage you to post the DTA script so I can "crib" that one and save some brain cells for more pleasant thoughts.

    If everything seems to be going well, you have obviously overlooked something.

    Ron

    Please help us, help you -before posting a question please read[/url]
    Before posting a performance problem please read[/url]

  • I think I will be posting those solutions to my blog instead.

    Jason...AKA CirqueDeSQLeil
    _______________________________________________
    I have given a name to my pain...MCM SQL Server, MVP
    SQL RNNR
    Posting Performance Based Questions - Gail Shaw[/url]
    Learn Extended Events

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