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Message Posted: Tue, 19 Feb 2008 @ 14:42:07 GMT


     
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Subj:   Re: Query randomly running for long time
 
From:   Fenwick, Ruth

Are there current statistics on the fast loaded 'key table', the one you say you drop and re-create?

If so, are they current every day with this query runs? Could it be a timing issue? I've seen cases were the query runs before the stats job 'sometimes', which could cause your issue. When you come along and look a few minutes later, the stats are 'up to date'.

If there are no stats, it could be due to random amp sampling and skew.....when you drop the table and recreate it, it will have a different tableid, which would probably result in another AMP being sampled for stats, and if there's skew (or it's a small table and not all AMPS are populated), it's the luck of the draw whether the AMP is representative of the tables data. Collect appropriate stats if there aren't any.



     
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