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Re: Terrible performance of a specific query with lots of connections
Posted by: Ben Dowling
Date: September 10, 2009 09:02AM

Hi Rick,

The machine has 32G of ram so there isn't a problem there.

The query was initially a LEFT JOIN, but was rewritten as a subselect to try and reduce the amount of open tables, and to reduce the thrashing (if that is the cause of the problem). Since changing the query to a subselect the problem has been reduced but not eliminated. On a server with no load the subselect is still marginally faster than the left join too.

Thanks, Ben

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