The events_stages_current Table

The events_stages_current table contains current stage events, one row per thread showing the current status of the thread's most recent monitored stage event.

The events-stages-current table can be truncated with TRUNCATE TABLE.

Of the tables that contain stage event rows, events_stages_current is the most fundamental. Other tables that contain stage event rows are logically derived from the current events. For example, the events_stages_history and events_stages_history_long tables are collections of the most recent stage events, up to a fixed number of rows.

The events_stages_current table has these columns:

• THREAD_ID

  The thread associated with the event. The THREAD_ID and EVENT_ID values taken together form a primary key that uniquely identifies the row. No two rows will have the same pair of values.

• EVENT_ID

  The thread current event number when the event starts.

• END_EVENT_ID

  This column is set to NULL when the event starts, and updated to the thread current event number when the event ends. This column was added in MariaDB 5.6.4.

• EVENT_NAME

  The name of the instrument that produced the event. This is a setup_instruments.NAME value. Instrument names have multiple parts and form a hierarchy, as discussed in , "Performance Schema Instrument Naming Conventions".

• SOURCE

  The name of the source file containing the instrumented code that produced the event and the line number in the file at which the instrumentation occurs. This enables you to check the source to determine exactly what code is involved.

• TIMER_START, TIMER_END, TIMER_WAIT

  Timing information for the event. The unit for these values is picoseconds (trillionths of a second). The TIMER_START and TIMER_END values indicate when event timing started and ended. TIMER_WAIT is the event elapsed time (duration).

  If an event has not finished, TIMER_END and TIMER_WAIT are NULL.

  If an event is produced from an instrument that has TIMED = NO, timing information is not collected, and TIMER_START, TIMER_END, and TIMER_WAIT are all NULL.

  For discussion of picoseconds as the unit for event times and factors that affect time values, see , "Performance Schema Event Timing".

• NESTING_EVENT_ID

  The EVENT_ID value of the event within which this event is nested. The nesting event for a stage event is usually a statement event.

• NESTING_EVENT_TYPE

  The nesting event type. The value is statement, stage, or wait.

The events_stages_current table was added in MariaDB 5.6.3.

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