## 27.12.20.6 Object Wait Summary Table 

The Performance Schema maintains the objects_summary_global_by_type  table for aggregating object wait events. 

Example object wait event summary information: 

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 ... 

The objects_summary_global_by_type  table has these grouping columns to indicate how the table aggregates events: OBJECT_TYPE , OBJECT_SCHEMA , and OBJECT_NAME . Each row summarizes events for the given object. 

objects_summary_global_by_type  has the same summary columns as the events_waits_summary_by_ xxx  tables. See Section 27.12.20.1, “Wait Event Summary Tables” . 

The objects_summary_global_by_type  table has these indexes: 

•Primary key on ( OBJECT_TYPE , OBJECT_SCHEMA , OBJECT_NAME ) 

TRUNCATE TABLE  is permitted for the object summary table. It resets the summary columns to zero rather than removing rows. 

## 27.12.20.7 File I/O Summary Tables 

The Performance Schema maintains file I/O summary tables that aggregate information about I/O operations. 

Example file I/O event summary information: 

mysql> SELECT * FROM performance_schema.file_summary_by_event_name\G ... *************************** 2. row *************************** EVENT_NAME: wait/io/file/sql/binlog COUNT_STAR: 31 SUM_TIMER_WAIT: 8243784888 MIN_TIMER_WAIT: 0 AVG_TIMER_WAIT: 265928484 MAX_TIMER_WAIT: 6490658832 ... 

