29.12.3.2 The file_instances Table

The file_instances table lists all the files seen by the Performance Schema when executing file I/O instrumentation. If a file on disk has never been opened, it is not shown in file_instances. When a file is deleted from the disk, it is also removed from the file_instances table.

The file_instances table has these columns:

• FILE_NAME

  The file name.

• EVENT_NAME

  The instrument name associated with the file.

• OPEN_COUNT

  The count of open handles on the file. If a file was opened and then closed, it was opened 1 time, but OPEN_COUNT is 0. To list all the files currently opened by the server, use WHERE OPEN_COUNT > 0.

The file_instances table has these indexes:

• Primary key on (FILE_NAME)

• Index on (EVENT_NAME)

TRUNCATE TABLE is not permitted for the file_instances table.