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Performance Schema file_summary_by_event_name Table

The Performance Schema file_summary_by_event_name table contains file events summarized by event name. As of MariaDB 10.0, it contains the following columns:

Column Description
EVENT_NAME Event name.
COUNT_STAR Number of summarized events
SUM_TIMER_WAIT Total wait time of the summarized events that are timed.
MIN_TIMER_WAIT Minimum wait time of the summarized events that are timed.
AVG_TIMER_WAIT Average wait time of the summarized events that are timed.
MAX_TIMER_WAIT Maximum wait time of the summarized events that are timed.
COUNT_READ Number of all read operations, including FGETS, FGETC, FREAD, and READ.
SUM_TIMER_READ Total wait time of all read operations that are timed.
MIN_TIMER_READ Minimum wait time of all read operations that are timed.
AVG_TIMER_READ Average wait time of all read operations that are timed.
MAX_TIMER_READ Maximum wait time of all read operations that are timed.
SUM_NUMBER_OF_BYTES_READ Bytes read by read operations.
COUNT_WRITE Number of all write operations, including FPUTS, FPUTC, FPRINTF, VFPRINTF, FWRITE, and PWRITE.
SUM_TIMER_WRITE Total wait time of all write operations that are timed.
MIN_TIMER_WRITE Minimum wait time of all write operations that are timed.
AVG_TIMER_WRITE Average wait time of all write operations that are timed.
MAX_TIMER_WRITE Maximum wait time of all write operations that are timed.
SUM_NUMBER_OF_BYTES_WRITE Bytes written by write operations.
COUNT_MISC Number of all miscellaneous operations not counted above, including CREATE, DELETE, OPEN, CLOSE, STREAM_OPEN, STREAM_CLOSE, SEEK, TELL, FLUSH, STAT, FSTAT, CHSIZE, RENAME, and SYNC.
SUM_TIMER_MISC Total wait time of all miscellaneous operations that are timed.
MIN_TIMER_MISC Minimum wait time of all miscellaneous operations that are timed.
AVG_TIMER_MISC Average wait time of all miscellaneous operations that are timed.
MAX_TIMER_MISC Maximum wait time of all miscellaneous operations that are timed.

Before MariaDB 10, the table contained only the EVENT_NAME, COUNT_READ, COUNT_WRITE, SUM_NUMBER_OF_BYTES_READ and SUM_NUMBER_OF_BYTES_WRITE columns.

I/O operations can be avoided by caching, in which case they will not be recorded in this table.

You can TRUNCATE the table, which will reset all counters to zero.

Example

SELECT * FROM file_summary_by_event_name\G
...
*************************** 49. row ***************************
               EVENT_NAME: wait/io/file/aria/MAD
               COUNT_STAR: 60
           SUM_TIMER_WAIT: 397234368
           MIN_TIMER_WAIT: 0
           AVG_TIMER_WAIT: 6620224
           MAX_TIMER_WAIT: 16808672
               COUNT_READ: 0
           SUM_TIMER_READ: 0
           MIN_TIMER_READ: 0
           AVG_TIMER_READ: 0
           MAX_TIMER_READ: 0
 SUM_NUMBER_OF_BYTES_READ: 0
              COUNT_WRITE: 0
          SUM_TIMER_WRITE: 0
          MIN_TIMER_WRITE: 0
          AVG_TIMER_WRITE: 0
          MAX_TIMER_WRITE: 0
SUM_NUMBER_OF_BYTES_WRITE: 0
               COUNT_MISC: 60
           SUM_TIMER_MISC: 397234368
           MIN_TIMER_MISC: 0
           AVG_TIMER_MISC: 6620224
           MAX_TIMER_MISC: 16808672
*************************** 50. row ***************************
               EVENT_NAME: wait/io/file/aria/control
               COUNT_STAR: 3
           SUM_TIMER_WAIT: 24055778544
           MIN_TIMER_WAIT: 0
           AVG_TIMER_WAIT: 8018592848
           MAX_TIMER_WAIT: 24027262400
               COUNT_READ: 1
           SUM_TIMER_READ: 24027262400
           MIN_TIMER_READ: 0
           AVG_TIMER_READ: 24027262400
           MAX_TIMER_READ: 24027262400
 SUM_NUMBER_OF_BYTES_READ: 52
              COUNT_WRITE: 0
          SUM_TIMER_WRITE: 0
          MIN_TIMER_WRITE: 0
          AVG_TIMER_WRITE: 0
          MAX_TIMER_WRITE: 0
SUM_NUMBER_OF_BYTES_WRITE: 0
               COUNT_MISC: 2
           SUM_TIMER_MISC: 28516144
           MIN_TIMER_MISC: 0
           AVG_TIMER_MISC: 14258072
           MAX_TIMER_MISC: 27262208
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https://mariadb.com/kb/en/performance-schema-file_summary_by_event_name-table/