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Re: MySQL 5.6 Upgrade - Hung On Creating sort index
Posted by: Rick James
Date: October 16, 2016 04:56PM

Pre-5.6 did a nasty job of

FROM ( SELECT ... )
JOIN ( SELECT ... )

because neither 'derived' table had an index, so that required lots of table scans.

5.6 improved that for _most_ cases by creating the 'best' index for a derived table. Sometimes it was less than optimal.

Please provide SHOW CREATE TABLE for the tables, plus EXPLAIN SELECT (from both machines, if possible).

We can probably advise on how to speed up your query, in spite of the slowdown.

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Re: MySQL 5.6 Upgrade - Hung On Creating sort index
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October 16, 2016 04:56PM


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