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Performance Schema file_summary_by_instance Table

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

Column Description
FILE_NAME File name.
EVENT_NAME Event name.
OBJECT_INSTANCE_BEGIN Address in memory. Together with FILE_NAME and EVENT_NAME uniquely identifies a row.
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 FILE_NAME, 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_instance\G
...
*************************** 204. row ***************************
                FILE_NAME: /var/lib/mysql/test/db.opt
               EVENT_NAME: wait/io/file/sql/dbopt
    OBJECT_INSTANCE_BEGIN: 140578961971264
               COUNT_STAR: 6
           SUM_TIMER_WAIT: 39902495024
           MIN_TIMER_WAIT: 177888
           AVG_TIMER_WAIT: 6650415692
           MAX_TIMER_WAIT: 21026400404
               COUNT_READ: 1
           SUM_TIMER_READ: 21026400404
           MIN_TIMER_READ: 21026400404
           AVG_TIMER_READ: 21026400404
           MAX_TIMER_READ: 21026400404
 SUM_NUMBER_OF_BYTES_READ: 65
              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: 5
           SUM_TIMER_MISC: 18876094620
           MIN_TIMER_MISC: 177888
           AVG_TIMER_MISC: 3775218924
           MAX_TIMER_MISC: 18864558060
*************************** 205. row ***************************
                FILE_NAME: /var/log/mysql/mariadb-bin.000157
               EVENT_NAME: wait/io/file/sql/binlog
    OBJECT_INSTANCE_BEGIN: 140578961971968
               COUNT_STAR: 6
           SUM_TIMER_WAIT: 73985877680
           MIN_TIMER_WAIT: 251136
           AVG_TIMER_WAIT: 12330979468
           MAX_TIMER_WAIT: 73846656340
               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: 2
          SUM_TIMER_WRITE: 62583004
          MIN_TIMER_WRITE: 27630192
          AVG_TIMER_WRITE: 31291284
          MAX_TIMER_WRITE: 34952812
SUM_NUMBER_OF_BYTES_WRITE: 369
               COUNT_MISC: 4
           SUM_TIMER_MISC: 73923294676
           MIN_TIMER_MISC: 251136
           AVG_TIMER_MISC: 18480823560
           MAX_TIMER_MISC: 73846656340
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https://mariadb.com/kb/en/performance-schema-file_summary_by_instance-table/