系统表介绍
performance_timers 报了时间计时器信息
| 列名 | 含义 |
|---|---|
| TIMER_NAME | 计时器名称 |
| TIMER_FREQUENCY | 时钟频率 |
| TIMER_RESOLUTION | 时钟精度 |
| TIMER_OVERHEAD | 周期开销 |
实例
mysql> SELECT * FROM performance_schema.performance_timers;
+-------------+-----------------+------------------+----------------+
| TIMER_NAME | TIMER_FREQUENCY | TIMER_RESOLUTION | TIMER_OVERHEAD |
+-------------+-----------------+------------------+----------------+
| CYCLE | 2389029850 | 1 | 72 |
| NANOSECOND | 1000000000 | 1 | 112 |
| MICROSECOND | 1000000 | 1 | 136 |
| MILLISECOND | 1036 | 1 | 168 |
| TICK | 105 | 1 | 2416 |
+-------------+-----------------+------------------+----------------+