As of MySQL 5.6.3, 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.
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.
For information about configuration of stage event collection, see Section 22.10.5, “Performance Schema Stage Event Tables”.
The events_stages_current table
has these columns:
THREAD_ID, EVENT_ID
The thread associated with the event and the thread
current event number when the event starts. The
THREAD_ID and
EVENT_ID values taken together uniquely
identify the row. No two rows have the same pair of
values.
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 MySQL
5.6.4.
EVENT_NAME
The name of the instrument that produced the event. This
is a NAME value from the
setup_instruments table.
Instrument names may have multiple parts and form a
hierarchy, as discussed in
Section 22.5, “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 before MySQL 5.6.26. As of 5.6.26,
TIMER_END is the current timer value
and TIMER_WAIT is the time elapsed so
far (TIMER_END −
TIMER_START).
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 Section 22.3.1, “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.
TRUNCATE TABLE is permitted for
the events_stages_current table.
It removes the rows.