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MySQL 5.7 Reference Manual  /  ...  /  Performance Schema Summary Tables

25.11.15 Performance Schema Summary Tables

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

Wait Event Summaries

Stage Summaries

Statement Summaries

Transaction Summaries

Object Wait Summaries

File I/O Summaries

Table I/O and Lock Wait Summaries

Socket Summaries

Memory Summaries

Status Variable Summaries

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. Generally, 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. Exceptions to this truncation behavior are noted in individual summary table sections.


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