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10.4.2 The events_waits_history Table

The events_waits_history table contains the N most recent wait events that have ended per thread. Wait events are not added to the table until they have ended. When the table contains the maximum number of rows for a given thread, the oldest thread row is discarded when a new row for that thread is added. When a thread ends, all its rows are discarded.

The Performance Schema autosizes the value of N during server startup. To set the number of rows per thread explicitly, set the performance_schema_events_waits_history_size system variable at server startup.

The events_waits_history table has the same columns as events_waits_current. See Section 10.4.1, “The events_waits_current Table”.

TRUNCATE TABLE is permitted for the events_waits_history table. It removes the rows.

For more information about the relationship between the three wait event tables, see Performance Schema Tables for Current and Historical Events.

For information about configuring whether to collect wait events, see Section 10.4, “Performance Schema Wait Event Tables”.


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