Performance Schema Summary Tables The Performance Schema maintains tables for collecting current and recent stage events, and aggregates that information in summary tables. Section 27.12.5, “Performance Schema Stage Event Tables”  describes the events on which stage summaries are based. See that discussion for information about the content of stage events, the current and historical stage event tables, and how to control stage event collection, which is disabled by default. Example stage event summary information: mysql>  SELECT * FROM performance_schema.events_stages_summary_global_by_event_name\G ... *************************** 5. row *************************** EVENT_NAME: stage/sql/checking permissions COUNT_STAR: 57 SUM_TIMER_WAIT: 26501888880 MIN_TIMER_WAIT: 7317456 AVG_TIMER_WAIT: 464945295 MAX_TIMER_WAIT: 12858936792 ... *************************** 9. row *************************** EVENT_NAME: stage/sql/closing tables COUNT_STAR: 37 SUM_TIMER_WAIT: 662606568 MIN_TIMER_WAIT: 1593864 AVG_TIMER_WAIT: 17907891 MAX_TIMER_WAIT: 437977248 ... Each stage summary table has one or more grouping columns to indicate how the table aggregates events. Event names refer to names of event instruments in the  setup_instruments  table: • events_stages_summary_by_account_by_event_name  has  EVENT_NAME ,  USER , and  HOST columns. Each row summarizes events for a given account (user and host combination) and event name. • events_stages_summary_by_host_by_event_name  has  EVENT_NAME  and  HOST  columns. Each row summarizes events for a given host and event name. • events_stages_summary_by_thread_by_event_name  has  THREAD_ID  and  EVENT_NAME columns. Each row summarizes events for a given thread and event name. • events_stages_summary_by_user_by_event_name  has  EVENT_NAME  and  USER  columns. Each row summarizes events for a given user and event name. • events_stages_summary_global_by_event_name  has an  EVENT_NAME  column. Each row summarizes events for a given event name. Each stage summary table has these summary columns containing aggregated values:  COUNT_STAR , SUM_TIMER_WAIT ,  MIN_TIMER_WAIT ,  AVG_TIMER_WAIT , and  MAX_TIMER_WAIT . These columns are analogous to the columns of the same names in the wait event summary tables (see Section 27.12.20.1, “Wait Event Summary Tables” ), except that the stage summary tables aggregate events from events_stages_current  rather than  events_waits_current . The stage summary tables have these indexes: • events_stages_summary_by_account_by_event_name : •Primary key on ( USER ,  HOST ,  EVENT_NAME ) • events_stages_summary_by_host_by_event_name : 5053