Re: Subquery with range uses filesort
Posted by:
Rick James
Date: November 19, 2013 04:10PM
But is the filesort really hurting performance?
A "filesort" may happen in RAM, not really on disk. But these two things:
> select * from Player
> `PlayerPassword` tinyblob NOT NULL,
conspire to force the temp table to be on disk. There are several rules covering when a temp table is MEMORY vs MyISAM. One of them is the existence of a BLOB field. (I did not spot anything else that would force disk.)
Are you fetching info about _one_ player? Or several players?
If you are looking at only a single player, then it is fairly easy to use a subquery (perhaps like the one I suggested). Fetching "the last ..." for several players in a single query is more complex.
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Re: Subquery with range uses filesort
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