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MySQL 5.5 Reference Manual  /  MySQL Performance Schema  /  Performance Schema Table Descriptions

22.7 Performance Schema Table Descriptions

Tables in the performance_schema database can be grouped as follows:

  • Setup tables. These tables are used to configure and display monitoring characteristics.

  • Current events table. The events_waits_current table contains the most recent event for each thread.

  • History tables. These tables have the same structure as events_waits_current but contain more rows. The events_waits_history table contains the most recent 10 events per thread. events_waits_history_long contains the most recent 10,000 events.

    To change the sizes of these tables, set the performance_schema_events_waits_history_size and performance_schema_events_waits_history_long_size system variables at server startup.

  • Summary tables. These tables contain information aggregated over groups of events, including those that have been discarded from the history tables.

  • Instance tables. These tables document what types of objects are instrumented. An instrumented object, when used by the server, produces an event. These tables provide event names and explanatory notes or status information.

  • Miscellaneous tables. These do not fall into any of the other table groups.

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