系统表介绍
events_waits_current 记录了当前等待事件，表中一行显示一个线程最近被监测到的等待事件。
| 列名 | 含义 |
|---|---|
| THREAD_ID | 线程编号 |
| EVENT_ID | 事件编号 |
| END_EVENT_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 |
| SPINS | 自旋次数 |
| OBJECT_SCHEMA | 作用对象所属模式 |
| OBJECT_NAME | 作用对象名 |
| INDEX_NAME | 索引名 |
| OBJECT_TYPE | 对象类型 |
| OBJECT_INSTANCE_BEGIN | 对象内存地址 |
| NESTING_EVENT_ID | 嵌套事件编号 |
| NESTING_EVENT_TYPE | 嵌套事件类型 值为 TRANSACTION, STATEMENT, STAGE 或 WAIT. |
| OPERATION | 操作 |
| NUMBER_OF_BYTES | 操作读写的字节数 |
| FLAGS | 保留 |
实例
mysql> SELECT * FROM performance_schema.events_waits_current \G ;
*************************** 1. row ***************************
THREAD_ID: 13
EVENT_ID: 192
END_EVENT_ID: 192
EVENT_NAME: wait/io/file/innodb/innodb_data_file
SOURCE:
TIMER_START: 387295918107116016
TIMER_END: 387295918123567520
TIMER_WAIT: 16451504
SPINS: NULL
OBJECT_SCHEMA: NULL
OBJECT_NAME: /data/mysql/ibtmp1
INDEX_NAME: NULL
OBJECT_TYPE: FILE
OBJECT_INSTANCE_BEGIN: 140391138327872
NESTING_EVENT_ID: NULL
NESTING_EVENT_TYPE: NULL
OPERATION: write
NUMBER_OF_BYTES: 16384
FLAGS: NULL
*************************** 2. row ***************************
THREAD_ID: 346
EVENT_ID: 183
END_EVENT_ID: 183
EVENT_NAME: idle
SOURCE:
TIMER_START: 12385890639152000000
TIMER_END: 12385924254784000000
TIMER_WAIT: 33615632000000
SPINS: NULL
OBJECT_SCHEMA: NULL
OBJECT_NAME: NULL
INDEX_NAME: NULL
OBJECT_TYPE: NULL
OBJECT_INSTANCE_BEGIN: 0
NESTING_EVENT_ID: NULL
NESTING_EVENT_TYPE: NULL
OPERATION: idle
NUMBER_OF_BYTES: NULL
FLAGS: NULL
*************************** 3. row ***************************
THREAD_ID: 348
EVENT_ID: 86
END_EVENT_ID: NULL
EVENT_NAME: idle
SOURCE:
TIMER_START: 12385873962321000000
TIMER_END: 12385924254988000000
TIMER_WAIT: 50292667000000
SPINS: NULL
OBJECT_SCHEMA: NULL
OBJECT_NAME: NULL
INDEX_NAME: NULL
OBJECT_TYPE: NULL
OBJECT_INSTANCE_BEGIN: 0
NESTING_EVENT_ID: NULL
NESTING_EVENT_TYPE: NULL
OPERATION: idle
NUMBER_OF_BYTES: NULL
FLAGS: NULL
*************************** 4. row ***************************
THREAD_ID: 349
EVENT_ID: 1391
END_EVENT_ID: NULL
EVENT_NAME: idle
SOURCE:
TIMER_START: 12385874463590000000
TIMER_END: 12385924254991000000
TIMER_WAIT: 49791401000000
SPINS: NULL
OBJECT_SCHEMA: NULL
OBJECT_NAME: NULL
INDEX_NAME: NULL
OBJECT_TYPE: NULL
OBJECT_INSTANCE_BEGIN: 0
NESTING_EVENT_ID: NULL
NESTING_EVENT_TYPE: NULL
OPERATION: idle
NUMBER_OF_BYTES: NULL
FLAGS: NULL
*************************** 5. row ***************************
THREAD_ID: 350
EVENT_ID: 37
END_EVENT_ID: NULL
EVENT_NAME: idle
SOURCE:
TIMER_START: 12385871511113000000
TIMER_END: 12385924254993000000
TIMER_WAIT: 52743880000000
SPINS: NULL
OBJECT_SCHEMA: NULL
OBJECT_NAME: NULL
INDEX_NAME: NULL
OBJECT_TYPE: NULL
OBJECT_INSTANCE_BEGIN: 0
NESTING_EVENT_ID: NULL
NESTING_EVENT_TYPE: NULL
OPERATION: idle
NUMBER_OF_BYTES: NULL
FLAGS: NULL
*************************** 6. row ***************************
THREAD_ID: 351
EVENT_ID: 131
END_EVENT_ID: NULL
EVENT_NAME: idle
SOURCE:
TIMER_START: 12385390404364000000
TIMER_END: 12385924254996000000
TIMER_WAIT: 533850632000000
SPINS: NULL
OBJECT_SCHEMA: NULL
OBJECT_NAME: NULL
INDEX_NAME: NULL
OBJECT_TYPE: NULL
OBJECT_INSTANCE_BEGIN: 0
NESTING_EVENT_ID: NULL
NESTING_EVENT_TYPE: NULL
OPERATION: idle
NUMBER_OF_BYTES: NULL
FLAGS: NULL
6 rows in set (0.00 sec)
ERROR:
No query specified