MySQL Forums
Forum List  »  Optimizer & Parser

Re: Subquery with range uses filesort
Posted by: David Marcus
Date: November 19, 2013 08:36PM

> But is the filesort really hurting performance?

I don't know. I could test it, with some effort. But, if the query
returns a few hundred or thousand players and MySQL has to sort a
dozen or a hundred records for each player, I would think the sorting
would take a noticeable amount of time.

> > select * from Player
> > `PlayerPassword` tinyblob NOT NULL,
> conspire to force the temp table to be on disk.

I'm not actually fetching that column.

The temp table is declared "engine=memory". I used to not specify the
engine for the temp table. When my hosting company upgraded MySQL,
queries started timing out. I figured out that the temp table had
switched from MyISAM to InnoDB. With InnoDB, updating one row of the
temp table took 0.1 second. With a memory table, 0.0001 seconds.

> Are you fetching info about _one_ player? Or several players?

People enter criteria on

http://www.ratingscentral.com/PlayerSearch.php

The results can contain anywhere from one player to 54,106.

Options: ReplyQuote


Subject
Views
Written By
Posted
3883
November 16, 2013 02:42PM
1387
November 17, 2013 07:42PM
1390
November 17, 2013 08:01PM
1377
November 18, 2013 04:33PM
1916
November 18, 2013 07:54PM
1612
November 19, 2013 04:10PM
Re: Subquery with range uses filesort
1457
November 19, 2013 08:36PM
1552
November 21, 2013 02:55PM
1758
December 05, 2013 03:46PM
1395
December 07, 2013 02:10PM
1370
December 09, 2013 06:08PM
1379
December 14, 2013 09:51PM
1340
December 14, 2013 10:17PM
1424
December 15, 2013 11:29PM
1453
December 17, 2013 06:58PM
1385
December 18, 2013 05:49PM
1451
December 18, 2013 08:28PM
1485
December 19, 2013 10:13PM
1466
December 19, 2013 10:28PM
1315
December 20, 2013 07:06PM
1399
December 21, 2013 07:36AM
1454
December 22, 2013 10:01AM
1501
December 22, 2013 10:45AM
1363
December 25, 2013 09:30PM


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.