22.7.5 Performance Schema Summary Tables Event Wait Summary Tables File I/O Summary Tables

Summary tables provide aggregated information for terminated events over time. The tables in this group summarize event data in different ways.

Event Wait Summaries:

File I/O Summaries:

The events_waits_summary_global_by_event_name table was named EVENTS_WAITS_SUMMARY_BY_EVENT_NAME before MySQL 5.5.7.

Each summary table has grouping columns that determine how to group the data to be aggregated, and summary columns that contain the aggregated values. Tables that summarize events in similar ways often have similar sets of summary columns and differ only in the grouping columns used to determine how events are aggregated.

Summary tables can be truncated with TRUNCATE TABLE. The effect is to reset the summary columns to 0 or NULL, not to remove rows. This enables you to clear collected values and restart aggregation. That might be useful, for example, after you have made a runtime configuration change.