MySQL 5.1.56 packages are now available on Dotdeb :
- for Debian 6.0 “Squeeze” and Debian 5.0 “Lenny”
- for the amd64 and i386 architectures
Of course, the corresponding Pinba storage engine has been rebuilt (Squeeze only). But take care to the plugin-load directive in your /etc/mysql/my.cnf file : MySQL does not support several plugin-load directives and always keep the last read. Then if you want, for example, use the Pinba storage engine while having the the InnoDB plugin loaded, you should uncomment the following line.
And, as usual, please read the Changelog of this maintainance release before upgrading.