I have been looking into Percona (
Percona Server with XtraDB - Percona Software), potentially for use as a surrogate for MySQL. Percona claims to be self tuning. What does it really mean to be self tuning for a database server, in the general sense? Apart from configuration parameters, such as the cache query size, there could also be some more complex tuning measures such as indexes and storage engines (use memory based storage engine for small but often used data).
How much awareness can be given to a database server for it to be self tuning? Surely there must be limits?