The setup_actors table contains information that determines whether to enable monitoring for new foreground server threads (threads associated with client connections). This table has a maximum size of 100 rows by default. To change the table size, modify the performance_schema_setup_actors_size system variable at server startup.

For each new foreground thread, the Performance Schema matches the user and host for the thread against the rows of the setup_actors table. If a row from that table matches, its ENABLED column value is used to set the INSTRUMENTED column of the threads table row for the thread. This enables instrumenting to be applied selectively per host, user, or account (user and host combination). If there is no match, the INSTRUMENTED column for the thread is set to NO.

For background threads, there is no associated user. INSTRUMENTED is YES by default and setup_actors is not consulted.

The initial contents of the setup_actors table match any user and host combination, so monitoring is enabled by default for all foreground threads:

mysql> SELECT * FROM performance_schema.setup_actors;
+------+------+------+
| HOST | USER | ROLE |
+------+------+------+
| %    | %    | %    |
+------+------+------+

For information about how to use the setup_actors table to affect event monitoring, see Section 22.4.6, “Pre-Filtering by Thread”.

Modifications to the setup_actors table affect only foreground threads created subsequent to the modification, not existing threads. To affect existing threads, modify the INSTRUMENTED column of threads table rows.

The setup_actors table has these columns:

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