系统表介绍
events_stages_history 表包含历史捕获的SQL运行时各种阶段性事件。 该表用一行记录描述一个线程最近被监测到的阶段性事件。
每个线程记录的数量受参数“performance_schema_events_stages_history_size” 控制
| 列名 | 含义 |
|---|---|
| THREAD_ID | 线程ID |
| EVENT_ID | 事件ID |
| END_EVENT_ID | 阶段结束事件ID 当事件结束后，发生启动修改线程当前事件号时置为空 |
| EVENT_NAME | 事件名称 |
| SOURCE | 包含监测器的源码文件 |
| TIMER_START | 事件启动的时间 |
| TIMER_END | 事件结束的时间 |
| TIMER_WAIT | 事件持续时长 TIMER_END-TIMER_START 单位是皮秒 百万分之一微秒 |
| WORK_COMPLETED | 工作单元被完成的数量 |
| WORK_ESTIMATED | 预计需要被完成的工作数量 |
| NESTING_EVENT_ID | 嵌套事件编号 |
| NESTING_EVENT_TYPE | 嵌套事件类型 |
实例
mysql> select * from events_stages_history ;
+-----------+----------+--------------+--------------------------------+--------+----------------------+----------------------+------------+----------------+----------------+------------------+--------------------+
| THREAD_ID | EVENT_ID | END_EVENT_ID | EVENT_NAME | SOURCE | TIMER_START | TIMER_END | TIMER_WAIT | WORK_COMPLETED | WORK_ESTIMATED | NESTING_EVENT_ID | NESTING_EVENT_TYPE |
+-----------+----------+--------------+--------------------------------+--------+----------------------+----------------------+------------+----------------+----------------+------------------+--------------------+
| 360 | 314 | 314 | stage/sql/Opening tables | | 12412759158965197000 | 12412759158969544000 | 4347000 | NULL | NULL | 306 | STATEMENT |
| 360 | 315 | 316 | stage/sql/init | | 12412759158969544000 | 12412759158982738000 | 13194000 | NULL | NULL | 306 | STATEMENT |
| 360 | 317 | 318 | stage/sql/optimizing | | 12412759158982738000 | 12412759158986834000 | 4096000 | NULL | NULL | 306 | STATEMENT |
| 360 | 319 | 319 | stage/sql/executing | | 12412759158986834000 | 12412759158994762000 | 7928000 | NULL | NULL | 306 | STATEMENT |
| 360 | 320 | 320 | stage/sql/end | | 12412759158994762000 | 12412759158996250000 | 1488000 | NULL | NULL | 306 | STATEMENT |
| 360 | 321 | 322 | stage/sql/query end | | 12412759158996250000 | 12412759158999455000 | 3205000 | NULL | NULL | 306 | STATEMENT |
| 360 | 323 | 323 | stage/sql/closing tables | | 12412759158999455000 | 12412759159000572000 | 1117000 | NULL | NULL | 306 | STATEMENT |
| 360 | 324 | 325 | stage/sql/freeing items | | 12412759159000572000 | 12412759159076303000 | 75731000 | NULL | NULL | 306 | STATEMENT |
| 360 | 326 | 327 | stage/sql/cleaning up | | 12412759159076303000 | 12412759159077921000 | 1618000 | NULL | NULL | 306 | STATEMENT |
| 360 | 313 | 313 | stage/sql/checking permissions | | 12412759158962074000 | 12412759158965197000 | 3123000 | NULL | NULL | 306 | STATEMENT |
| 362 | 1842 | 1844 | stage/sql/Opening tables | | 12413353441212853000 | 12413353441252179000 | 39326000 | NULL | NULL | 1833 | STATEMENT |
| 362 | 1845 | 1845 | stage/sql/init | | 12413353441252179000 | 12413353441285665000 | 33486000 | NULL | NULL | 1833 | STATEMENT |
| 362 | 1846 | 1848 | stage/sql/System lock | | 12413353441285665000 | 12413353441298176000 | 12511000 | NULL | NULL | 1833 | STATEMENT |
| 362 | 1849 | 1849 | stage/sql/optimizing | | 12413353441298176000 | 12413353441300512000 | 2336000 | NULL | NULL | 1833 | STATEMENT |
| 362 | 1850 | 1850 | stage/sql/statistics | | 12413353441300512000 | 12413353441314363000 | 13851000 | NULL | NULL | 1833 | STATEMENT |
| 362 | 1851 | 1852 | stage/sql/preparing | | 12413353441314363000 | 12413353441323378000 | 9015000 | NULL | NULL | 1833 | STATEMENT |
| 362 | 1853 | 1853 | stage/sql/executing | | 12413353441323378000 | 12413353441323846000 | 468000 | NULL | NULL | 1833 | STATEMENT |
| 362 | 1829 | 1830 | stage/sql/cleaning up | | 12413260508808398000 | 12413260508809326000 | 928000 | NULL | NULL | 1798 | STATEMENT |
| 362 | 1834 | 1839 | stage/sql/starting | | 12413353441094106000 | 12413353441198837000 | 104731000 | NULL | NULL | 1833 | STATEMENT |
| 362 | 1840 | 1841 | stage/sql/checking permissions | | 12413353441198837000 | 12413353441212853000 | 14016000 | NULL | NULL | 1833 | STATEMENT |
+-----------+----------+--------------+--------------------------------+--------+----------------------+----------------------+------------+----------------+----------------+------------------+--------------------+
20 rows in set (0.00 sec)
查看参数
mysql> show variables like 'performance_schema_events_stages_history_size' ;
+-----------------------------------------------+-------+
| Variable_name | Value |
+-----------------------------------------------+-------+
| performance_schema_events_stages_history_size | 10 |
+-----------------------------------------------+-------+
1 row in set (0.00 sec)