Reindex tables and update statistics
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I've been digging in the database that supports our software because it's always been known for having slow performance. I've looked through the daily maintenance plan, and I see that there is normal stuff such as shrinking the database, and reindexing the tables and such, but I can't find update statistics anywhere. I was under the impression that if you don't update statistics after reindex, then database does not know how to use the new indexes very well, and it does almost no good. Can anyone please explain how the whole process works, and what would be the downside of reindexing the tables with out updating statistics. The command they use for reindexing is "dbcc dbreindex"
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Just did some more checking, and it looks like database has Auto Update Statistics set True, so this may not be an issue.
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Shrinking the database, bad idea, especially if it is done after the index rebuild. Index rebuild rebuilds the statistics for the index. You should have a process the rebuilds statistics on a periodic basis, preferably with a full scan.
If you are using a maintenance plan, you don't have the granularity you really need. You should check out the routines available here: http://ola.hallengren.com/.
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An index rebuild updates the stats associated with that index as part of the rebuild operation
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverabilityWe walk in the dark places no others will enter
We stand on the bridge and no one may pass
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