系统表介绍
memory_summary_global_by_event_name 记录了事件对内存的使用,按照事件进行分组统计.
| 列名 | 含义 |
|---|---|
| EVENT_NAME | 事件名 |
| COUNT_ALLOC | 内存分配次数 |
| COUNT_FREE | 内存释放次数 |
| SUM_NUMBER_OF_BYTES_ALLOC | 总内存分配大小 |
| SUM_NUMBER_OF_BYTES_FREE | 总内存释放大小 |
| LOW_COUNT_USED | 当前持有的内存块数量 |
| CURRENT_COUNT_USED | 持有内存块的低水位线 |
| HIGH_COUNT_USED | 持有内存块的高水位线 |
| LOW_NUMBER_OF_BYTES_USED | 持有内存字节数的低水位线 |
| CURRENT_NUMBER_OF_BYTES_USED | 当前持有内存的数量 |
| HIGH_NUMBER_OF_BYTES_USED | 持有内存字节数的高水位线 |
实例
mysql> select * from memory_summary_global_by_event_name order by CURRENT_NUMBER_OF_BYTES_USED desc limit 2 \G;
*************************** 1. row ***************************
EVENT_NAME: memory/performance_schema/events_statements_history_long
COUNT_ALLOC: 1
COUNT_FREE: 0
SUM_NUMBER_OF_BYTES_ALLOC: 14320000
SUM_NUMBER_OF_BYTES_FREE: 0
LOW_COUNT_USED: 0
CURRENT_COUNT_USED: 1
HIGH_COUNT_USED: 1
LOW_NUMBER_OF_BYTES_USED: 0
CURRENT_NUMBER_OF_BYTES_USED: 14320000
HIGH_NUMBER_OF_BYTES_USED: 14320000
*************************** 2. row ***************************
EVENT_NAME: memory/performance_schema/events_statements_summary_by_digest.tokens
COUNT_ALLOC: 1
COUNT_FREE: 0
SUM_NUMBER_OF_BYTES_ALLOC: 10240000
SUM_NUMBER_OF_BYTES_FREE: 0
LOW_COUNT_USED: 0
CURRENT_COUNT_USED: 1
HIGH_COUNT_USED: 1
LOW_NUMBER_OF_BYTES_USED: 0
CURRENT_NUMBER_OF_BYTES_USED: 10240000
HIGH_NUMBER_OF_BYTES_USED: 10240000
2 rows in set (0.00 sec)