MySQL Forums
Forum List  »  Optimizer & Parser

Re: Simple Query - but explain worries me
Posted by: Konstantin Osipov
Date: January 02, 2006 05:22PM

I wouldn't worry about that unless there is a clear evidence that the new plan is slower.
The optimizer performes a few 'dives' into the index to estimate the average number of records in range, and based on that, chooses the join order.
As long as the query is as fast as in 4.1 there is nothing to worry about.
Bear in mind that 5.0 adds new table access methods, such as index merge, and has other interesting optimizations that can influence the choice of the execution plan.
So, to sum up:
- it would be nice to see the explain output
- there is nothing to worry about as long as the query is executed quickly enough

Options: ReplyQuote

Written By
November 01, 2005 01:26AM
November 01, 2005 02:48AM
November 01, 2005 05:13AM
November 01, 2005 07:37AM
November 01, 2005 08:03AM
Re: Simple Query - but explain worries me
January 02, 2006 05:22PM

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.