{"id":1099,"date":"2008-01-27T00:01:41","date_gmt":"2008-01-27T00:01:41","guid":{"rendered":"\/blogs\/paul\/post\/Search-Engine-QA-10-Rebuilding-Indexes-and-Updating-Statistics.aspx"},"modified":"2008-01-27T00:01:41","modified_gmt":"2008-01-27T00:01:41","slug":"search-engine-qa-10-rebuilding-indexes-and-updating-statistics","status":"publish","type":"post","link":"https:\/\/www.sqlskills.com\/blogs\/paul\/search-engine-qa-10-rebuilding-indexes-and-updating-statistics\/","title":{"rendered":"Search Engine Q&A #10: Rebuilding Indexes and Updating Statistics"},"content":{"rendered":"


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It seems like all I’ve been talking about on the forums the last couple of days is the correct order of operations in a maintenance plan. The biggest confusion seems to be about the effect of rebuilding an index on statistics, with some incorrect advice being given out on what to do.<\/P>
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Rebuilding an index will update statistics with the equivalent of a full scan – doesn’t matter whether you use DBCC DBREINDEX<\/FONT> or ALTER INDEX … REBUILD<\/FONT>, the effect is the same. It can do this because it sees a complete picture of the index while its doing the rebuild.<\/P>
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Reorganizing an index (using the old DBCC INDEXDEFRAG<\/FONT> I wrote, or the new ALTER INDEX … REORGANIZE<\/FONT>) will NOT update statistics at all, because it only sees a few pages of the index at a time.<\/P>
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The problem I’ve been seeing is people rebuilding indexes and then updating statistics. So why is this a problem? Well, it depends :-)<\/P>
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