# Performance Schema file\_summary\_by\_instance Table The [Performance Schema](https://mariadb.com/docs/server/reference/system-tables/performance-schema) `file_summary_by_instance` table contains file events summarized by instance. 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. | I/O operations can be avoided by caching, in which case they will not be recorded in this table. You can [TRUNCATE](https://mariadb.com/docs/server/reference/sql-statements/table-statements/truncate-table) the table, which will reset all counters to zero. ## Example ```sql 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 ``` *This page is licensed: CC BY-SA / Gnu FDL* {% @marketo/form formId="4316" %}