The CACHE/CLOSE utility is used to force, cluster-wide, all
    detached PMDF processes to close any open I/O channels that they
    have to the queue cache database. This is generally done for
    two reasons: to close all channels to the file so that it can be
    modified, and to force detached processes to re-open the queue
    cache database file so as to begin using any new version of that
    database.

    Sites using the TCP/IP channel, PMDF-LAN Lotus Notes channels,
    PMDF-XGS, Jnet (BN_SLAVE), the PMDF-DIRSYNC Lotus Notes directory
    agent, or FAX receive processes will have detached PMDF processes
    which may need to close channels to the database.