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22.9.2.2 The setup_instruments Table

The setup_instruments table lists classes of instrumented objects for which events can be collected:

mysql> SELECT * FROM setup_instruments;
+---------------------------------------------------+---------+-------+
| NAME                                              | ENABLED | TIMED |
+---------------------------------------------------+---------+-------+
...
| wait/synch/mutex/sql/LOCK_global_read_lock        | YES     | YES   |
| wait/synch/mutex/sql/LOCK_global_system_variables | YES     | YES   |
| wait/synch/mutex/sql/LOCK_lock_db                 | YES     | YES   |
| wait/synch/mutex/sql/LOCK_manager                 | YES     | YES   |
...
| wait/synch/rwlock/sql/LOCK_grant                  | YES     | YES   |
| wait/synch/rwlock/sql/LOGGER::LOCK_logger         | YES     | YES   |
| wait/synch/rwlock/sql/LOCK_sys_init_connect       | YES     | YES   |
| wait/synch/rwlock/sql/LOCK_sys_init_slave         | YES     | YES   |
...
| wait/io/file/sql/binlog                           | YES     | YES   |
| wait/io/file/sql/binlog_index                     | YES     | YES   |
| wait/io/file/sql/casetest                         | YES     | YES   |
| wait/io/file/sql/dbopt                            | YES     | YES   |
...

Each instrument added to the source code provides a row for the setup_instruments table, even when the instrumented code is not executed. When an instrument is enabled and executed, instrumented instances are created, which are visible in the xxx_instances tables, such as file_instances or rwlock_instances.

The setup_instruments table has these columns:

  • NAME

    The instrument name. Instrument names may have multiple parts and form a hierarchy, as discussed in Section 22.6, “Performance Schema Instrument Naming Conventions”. Events produced from execution of an instrument have an EVENT_NAME value that is taken from the instrument NAME value. (Events do not really have a name, but this provides a way to associate events with instruments.)

  • ENABLED

    Whether the instrument is enabled. The value is YES or NO. A disabled instrument produces no events. This column can be modified, although setting ENABLED has no effect for instruments that have already been created.

  • TIMED

    Whether the instrument is timed. The value is YES or NO. This column can be modified, although setting TIMED has no effect for instruments that have already been created.

    If an enabled instrument is not timed, the instrument code is enabled, but the timer is not. Events produced by the instrument have NULL for the TIMER_START, TIMER_END, and TIMER_WAIT timer values. This in turn causes those values to be ignored when calculating the sum, minimum, maximum, and average time values in summary tables.

TRUNCATE TABLE is not permitted for the setup_instruments table.


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