Comment 4 for bug 1297000

Interesting. Now that you mentioned, this could be indeed a bug where list_database does not make use of ignore_dbs conf, but uses hard coded strings in the query.

The ignore_dbs conf is used in ValidatedMySQLDatabase to make sure that any action that create/delete/update any databases is not applied in any of these databases defined here.

Could you verify if adding 'performance_schema' and 'test' in the ingore_dbs conf prevents these DBs to appear when being listed?. If it doesnt, then you have a bug and should be fixed by using the conf.