MySQL Forums
Forum List  »  Performance

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

Options: ReplyQuote

Sorry, you can't reply to this topic. It has been closed.

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.