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:

ColumnDescription
EVENT_NAMEEvent name.
COUNT_STARNumber of summarized events
SUM_TIMER_WAITTotal wait time of the summarized events that are timed.
MIN_TIMER_WAITMinimum wait time of the summarized events that are timed.
AVG_TIMER_WAITAverage wait time of the summarized events that are timed.
MAX_TIMER_WAITMaximum wait time of the summarized events that are timed.
COUNT_READNumber of all read operations, including FGETS, FGETC, FREAD, and READ.
SUM_TIMER_READTotal wait time of all read operations that are timed.
MIN_TIMER_READMinimum wait time of all read operations that are timed.
AVG_TIMER_READAverage wait time of all read operations that are timed.
MAX_TIMER_READMaximum wait time of all read operations that are timed.
SUM_NUMBER_OF_BYTES_READBytes read by read operations.
COUNT_WRITENumber of all write operations, including FPUTS, FPUTC, FPRINTF, VFPRINTF, FWRITE, and PWRITE.
SUM_TIMER_WRITETotal wait time of all write operations that are timed.
MIN_TIMER_WRITEMinimum wait time of all write operations that are timed.
AVG_TIMER_WRITEAverage wait time of all write operations that are timed.
MAX_TIMER_WRITEMaximum wait time of all write operations that are timed.
SUM_NUMBER_OF_BYTES_WRITEBytes written by write operations.
COUNT_MISCNumber 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_MISCTotal wait time of all miscellaneous operations that are timed.
MIN_TIMER_MISCMinimum wait time of all miscellaneous operations that are timed.
AVG_TIMER_MISCAverage wait time of all miscellaneous operations that are timed.
MAX_TIMER_MISCMaximum 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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