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Re: Huge performance differences between systems
Posted by: Rick James
Date: March 05, 2014 10:49PM

> SELECT field FROM table WHERE field IN (SELECT field FROM table)

Is known to optimize very poorly. (This will partially be fixed in 5.6 or 5.7)
Turn it into a JOIN.

Suggest you provide
SHOW CREATE TABLE
EXPLAIN SELECT ...
and other details about the naughty queries.

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Re: Huge performance differences between systems
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March 05, 2014 10:49PM


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