MySQL Forums
Forum List  »  Optimizer & Parser

Re: Query optimization
Posted by: Jan Kowalski
Date: May 22, 2013 08:08AM

I,ve read here http://www.mysqlperformanceblog.com/2011/10/13/when-explain-estimates-can-go-wrong/ that mysql uses “the number of rows” estimation to pick and choose indexes.
In my case explain shows 261099 rows when query uses status_modifiedgmt index without any forcement, and 260903 rows when I force type_status_date index. So why mysql stubbornly chooses status_modifiedgmt index?

Options: ReplyQuote


Subject
Views
Written By
Posted
2676
May 10, 2013 05:35AM
1310
May 12, 2013 08:42PM
1266
May 15, 2013 06:45AM
1285
May 15, 2013 08:35AM
1398
May 16, 2013 08:18AM
1329
May 17, 2013 03:52AM
1266
May 17, 2013 11:47PM
1173
May 21, 2013 08:51AM
Re: Query optimization
1319
May 22, 2013 08:08AM


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.