mysql> SELECT * FROM performance_schema.file_summary_by_instance\G ... *************************** 2. row *************************** FILE_NAME: /var/mysql/share/english/errmsg.sys EVENT_NAME: wait/io/file/sql/ERRMSG EVENT_NAME: wait/io/file/sql/ERRMSG OBJECT_INSTANCE_BEGIN: 4686193384 COUNT_STAR: 5 SUM_TIMER_WAIT: 13990154448 MIN_TIMER_WAIT: 26349624 AVG_TIMER_WAIT: 2798030607 MAX_TIMER_WAIT: 8150662536 ... 

Each file I/O summary table has one or more grouping columns to indicate how the table aggregates events. Event names refer to names of event instruments in the setup_instruments  table: 

• file_summary_by_event_name  has an EVENT_NAME  column. Each row summarizes events for a given event name. 

• file_summary_by_instance  has FILE_NAME , EVENT_NAME , and OBJECT_INSTANCE_BEGIN columns. Each row summarizes events for a given file and event name. 

Each file I/O summary table has the following summary columns containing aggregated values. Some columns are more general and have values that are the same as the sum of the values of more fine- grained columns. In this way, aggregations at higher levels are available directly without the need for user- defined views that sum lower-level columns. 

• COUNT_STAR , SUM_TIMER_WAIT , MIN_TIMER_WAIT , AVG_TIMER_WAIT , MAX_TIMER_WAIT 

These columns aggregate all I/O operations. 

• COUNT_READ , SUM_TIMER_READ , MIN_TIMER_READ , AVG_TIMER_READ , MAX_TIMER_READ , SUM_NUMBER_OF_BYTES_READ 

These columns aggregate all read operations, including FGETS , FGETC , FREAD , and READ . 

• COUNT_WRITE , SUM_TIMER_WRITE , MIN_TIMER_WRITE , AVG_TIMER_WRITE , MAX_TIMER_WRITE , SUM_NUMBER_OF_BYTES_WRITE 

These columns aggregate all write operations, including FPUTS , FPUTC , FPRINTF , VFPRINTF , FWRITE , and PWRITE . 

• COUNT_MISC , SUM_TIMER_MISC , MIN_TIMER_MISC , AVG_TIMER_MISC , MAX_TIMER_MISC 

These columns aggregate all other I/O operations, including CREATE , DELETE , OPEN , CLOSE , STREAM_OPEN , STREAM_CLOSE , SEEK , TELL , FLUSH , STAT , FSTAT , CHSIZE , RENAME , and SYNC . There are no byte counts for these operations. 

The file I/O summary tables have these indexes: 

• file_summary_by_event_name : 

•Primary key on ( EVENT_NAME ) 

• file_summary_by_instance : 

•Primary key on ( OBJECT_INSTANCE_BEGIN ) 

•Index on ( FILE_NAME ) 

