MySQL 8.4 Release Notes
29.12.20.6 对象等待汇总表
性能模式维护了objects_summary_global_by_type
表来聚合对象等待事件。
示例对象等待事件汇总信息:
mysql> SELECT * FROM performance_schema.objects_summary_global_by_type\G
...
*************************** 3. row ***************************
OBJECT_TYPE: TABLE
OBJECT_SCHEMA: test
OBJECT_NAME: t
COUNT_STAR: 3
SUM_TIMER_WAIT: 263126976
MIN_TIMER_WAIT: 1522272
AVG_TIMER_WAIT: 87708678
MAX_TIMER_WAIT: 258428280
...
*************************** 10. row ***************************
OBJECT_TYPE: TABLE
OBJECT_SCHEMA: mysql
OBJECT_NAME: user
COUNT_STAR: 14
SUM_TIMER_WAIT: 365567592
MIN_TIMER_WAIT: 1141704
AVG_TIMER_WAIT: 26111769
MAX_TIMER_WAIT: 334783032
...
对象objects_summary_global_by_type
表具有以下分组列来指示如何聚合事件:OBJECT_TYPE
,OBJECT_SCHEMA
和OBJECT_NAME
。每一行总结了给定对象的事件。
objects_summary_global_by_type
具有与events_waits_summary_by_
表相同的摘要列。请参阅第29.12.20.1节,“等待事件汇总表”。xxx
对象objects_summary_global_by_type
具有这些索引:
-
主键在(
OBJECT_TYPE
,OBJECT_SCHEMA
,OBJECT_NAME
)上
TRUNCATE TABLE
允许对对象汇总表进行。它将摘要列重置为零,而不是删除行。