After upgrading from MySQL 5.5 to 5.6, I started getting some warnings when running queries incommon_schema. For example:
+---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------+| Level | Code | Message|+---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------+| Warning | 1109 | Unknown table 'innodb_index_stats' in information_schema || Warning | 1109 | Unknown table 'innodb_index_stats' in information_schema || Warning | 1356 | View 'common_schema.processlist_repl' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them || Warning | 1356 | View 'common_schema.processlist_top' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them|| Warning | 1356 | View 'common_schema.slave_hosts' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them|| Warning | 1356 | View 'common_schema.slave_status' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them |+---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------+
The common_schema installer is good at accomodating whichever version of MySQL it is being installed on, but if you change that version it makes sense that common_schema needs to be re-installed. As stated in thedocumentation:
If you should upgrade your MySQL server, or enable features which were turned off during install of common_schema, the new feature set are not automatically available by common_schema, and a re-install of common_schema is required.
Apparently in MySQL 5.6 theinnodb_index_statstable has moved frominformation_schemato themysqlschema, so I submitted abug report. So far this isn’t affecting the way I use common_schema, but if it did the common_schema source code is very readable so it would probably be a simple patch.