[JonM]

Where can I get info on the MySQL 5.5 issues? I'm considering upgrading from 5.1 to get the new InnoDB plugin...

[asianexpress]

Just in case you weren't already aware, you can use the InnoDB plugin in 5.1 http://dev.mysql.com/doc/innodb-plugin/1.0/en/index.html

I know benchmarks don't put this quite as fast as 5.5, but there are still possible gains to be made.

[willvarfar]

Pssst look at tokudb