Re: Adding limit clause takes query from 2 seconds to 42 minutes

[Øystein Grøvlen]

Hi Josh,

Some questions:

Which version of MySQL are you using?

What are you comparing? The last insert statement with and without limit clause,
or the two different insert statements given? (If the latter, I am not surprised that there is a performance difference since only the latter involves a join. It is not clear to me What do you need this join for.)

Do you see the same slow-down if you use another storage engine, e.g. InnoDB, for the temporary table?

Do you see the same slow-down when inserting a limit clause for both the insert statement and the corresponding stand-alone select statement?

Øystein Grøvlen,
Senior Principal Software Engineer,
MySQL Group, Oracle,
Trondheim, Norway