Reopen_Interval=minutes

    After the specified interval, closes the current output file and
    opens a new output file without requiring you to exit from the
    Performance Monitor. The new output file has the same name as the
    previous output file, but the version number is incremented by 1.

    This qualifier allows you to view data written to the output file
    while the Performance Monitor is running.

    If there has been no database activity at the end of the
    specified interval, the current output file is not closed and
    a new output file is not created.

    Be careful not to use the DCL PURGE command inadvertently. Also
    note that use of the DCL SET FILE/VERSION_LIMIT command causes
    older versions of the output file to be deleted automatically.

    Use of the Reopen_Interval qualifier is only valid when you also
    specify the Output qualifier.