The CACHE/SYNCHRONIZE utility updates the active queue cache
    database by updating it to reflect all non-held message files
    currently present in the PMDF_QUEUE:[*] subdirectories.

    The PMDF CACHE/CLOSE command does not need to be issued in
    conjunction with the PMDF CACHE/SYNCHRONIZE command.

    The queue cache database is the file pointed at by the PMDF_
    QUEUE_CACHE_DATABASE logical. Normally, this is the file QUEUE_
    CACHE.DAT in the PMDF_TABLE: directory. This file should be
    protected against world and group access and be owned by the same
    UIC as the directory files QUEUE.DIR and LOG.DIR in the PMDF_
    ROOT: directory.