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Disk file operations I/O

Short Description

This wait event is used for disk file operations e.g. open, close, seek, and resize

Detailed Description​

This event is used to show waits for disk file operations (for example, open, close, seek, and resize). It is also used for miscellaneous I/O operations such as block dumps and password file accesses.

When the session in question is looked up in dynamic performance view V$SESSION_WAIT, the three parameters P1, P2 and P3 will show the Type of file operation (FileOperation), the file identification number (fileno) and the file type (filetype) respectively. The file type may be log file, data file, and so on.

How to reduce this wait​

After files have been opened, Oracle usually keeps files open, so after startup, if this is a significant activity, use the information in the parameters above to identify the file(s) in question. Look for unusual SQL which could cause open, close, seek and resize operations for example:

  • Undersized redo logs leading to:
    • Overly busy control files
    • Busy audit trails
    • Crashing processes creating trace files

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