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How often to update Statistics

  • August 19, 2011 at 11:35 am

    #1370918

    in my case, I have a couple of tables i need to update statistics on a couple of times a day in order to assure good performance.

    Typically you really only need to update specific tables, and not every table; Have you identified the tables that are affecting performance when the statsitics start varying a little bit?

    if you run UPDATE STATISTICS YOURTABLE WITH FULLSCAN; on that table, how long does it take?

    a 30 second slowdown when you run the command for a single table, as an example, will save lots of other queries from perforamnce degradation.

    Lowell

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  • August 20, 2011 at 1:29 pm

    #1371086

    Most systems I've managed we updated the statistics daily. But some were less volatile so we updated statistics weekly. You're approaching dealing with large databases at 1TB. You might need to modify your process so you do half the tables one night, half the next, or divide by thirds or something. There's no hard and fast numbers. We had a system that was so ill-designed that the stats go out of date in about 1/2 hour without firing the auto-update. So for one table in the system we were updating statistics every 10 minutes. You could tell it was happening, but it was that or watch the query plans get bad info and suddenly start performing horribly.

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