MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
      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 tables. The
          events_waits_current table
          contains the most recent event for each thread. Other similar
          tables contain current events at different levels of the event
          hierarchy: events_stages_current
          for stage events,
          events_statements_current for
          statement events, and
          events_transactions_current for
          transaction events.
        
          History tables. These tables have the same structure as the
          current events tables, but contain more rows. For example, for
          wait events, events_waits_history
          table contains the most recent 10 events per thread.
          events_waits_history_long
          contains the most recent 10,000 events. Other similar tables
          exist for stage, statement, and transaction histories.
        
          To change the sizes of the history tables, set the appropriate
          system variables at server startup. For example, to set the
          sizes of the wait event history tables, set
          performance_schema_events_waits_history_size
          and
          performance_schema_events_waits_history_long_size.
        
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.