Performance Schema performance_timers Table

The performance_timers table lists available event timers (cycle, nanosecond, microsecond, millisecond) and their overhead characteristics.

Description

The performance_timers table lists available event timers.

It contains the following columns:

Column	Description
TIMER_NAME	Time name, used in the setup_timers table.
TIMER_FREQUENCY	Number of timer units per second. Dependent on the processor speed.
TIMER_RESOLUTION	Number of timer units by which timed values increase each time.
TIMER_OVERHEAD	Minimum timer overhead, determined during initialization by calling the timer 20 times and selecting the smallest value. Total overhead will be at least double this, as the timer is called at the beginning and end of each timed event.

Any NULL values indicate that particular timer is not available on your platform, Any timer names with a non-NULL value can be used in the setup_timers table.

Example

SELECT * FROM performance_timers;
+-------------+-----------------+------------------+---------------------+
| TIMER_NAME  | TIMER_FREQUENCY | TIMER_RESOLUTION | TIMER_OVERHEAD      |
+-------------+-----------------+------------------+---------------------+
| CYCLE       |      2293651741 |                1 |                  28 |
| NANOSECOND  |      1000000000 |                1 |                  48 |
| MICROSECOND |         1000000 |                1 |                  52 |
| MILLISECOND |            1000 |             1000 | 9223372036854775807 |
| TICK        |             106 |                1 |                 496 |
+-------------+-----------------+------------------+---------------------+

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