When you have a non-trivial database installation, you will inevitably sooner or later encounter performance related issues ranging from a query not executing as fast as desirable to complete meltdowns where the database does not respond at all.

Until MySQL 5.5 the tools available to investigate what is going on inside MySQL were somewhat limited. Some of the tools were:

• The slow and general query logs
• The status counters available through SHOW [SESSION|GLOBAL] STATUS
• Storage engine status, e.g. SHOW ENGINE INNODB STATUS
• The EXPLAIN command to investigate the query plan of a SELECT statement
• SHOW PROFILE to profile one or more queries
• The MySQL error log

All of these tools are very useful, but also have their limitations, for example the SHOW STATUS mainly consists of counters that does not provide much insight into what is happening …

In the last weekend of September, MySQL Connect 2012 will take place in San Francisco as part of Oracle OpenWorld. MySQL Connect is a two day event that allows the attendees to focus on MySQL with the possibility to add on to Oracle OpenWorld or JavaOne.

I will be running the Hands-On Lab session Improving Performance with the MySQL Performance Schema (HOL10472) with the following abstract:

The Performance Schema is a tool first introduced in MySQL 5.5. It gives access to information about …

One significant new feature of MySQL 5.5 is the Performance Schema. I recently performed an upgrade from 5.0 to 5.5, however my check of differences in the MySQL variables via mysqladmin variables failed because we now have a new record long variable name “performance_schema_events_waits_history_long_size”.

The full list of new performance_schema variables are:

> | performance_schema_events_waits_history_long_size | 10000                                                                                                                  |
> | performance_schema_events_waits_history_size      | 10                                                                                                                     |
> | performance_schema_max_cond_classes               | 80 …