October 5, 2007

UNION vs UNION ALL Performance

Posted by peter

When I was comparing performance of UNION vs MySQL 5.0 index merge algorithm Sinisa pointed out I should be using UNION ALL instead of simple UNION in my benchmarks, and he was right. Numbers would be different but it should not change general point of having optimization of moving LIMIT inside of union clause being cool thing.

But So is UNION ALL indeed faster than UNION DISTINCT (the UNION is shortcut for UNION DISTINCT) ?
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Posted by peter @ 2:01 pm :: benchmarks, optimizer :: 9 comments
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What did we want Interns to do

Posted by peter

About one month ago we posted a call for interns to work with us on various MySQL Performance related things.

We got good number of replies and a lot of people wondered what tasks exactly we could offer as surely this sort of involvement should be fun and should teach you something.
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Posted by peter @ 10:35 am :: community :: 1 comment
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