Spec-Zone .ru
спецификации, руководства, описания, API
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Spec-Zone .ru
спецификации, руководства, описания, API
|
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 MySQL 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 Section
21.4, "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 Section 21.2.3.1, "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.
The events_stages_current
table was added in MySQL 5.6.3.