When you use row caches, it is possible for a large number
    of database records to be modified in row cache areas. These
    modified records must be written to the physical database files
    on disk at various times, such as backing up or verifying
    the database, or when closing the database. The RMU Server
    Record_Cache Checkpoint command causes the RCS process to
    immediately write all modified records from all row cache areas
    back to the physical database files on disk.

    If there are a large number of modified records to be written
    back to the database, this operation can take a long time.