/FAST_LOAD (default)
       /NOFAST_LOAD

    This qualifier controls whether or not the fast load algorithm
    is used. If /FAST_LOAD is specified, callable CONVERT is used
    to build the database. A new database is always created. If
    records with duplicate keys (left hand sides) are encountered
    in the input stream and /NODUPLICATE is in effect, the specific
    occurrence that will be used is unpredictable.

    /NOFAST_LOAD is a synonym for for /APPEND.