The CKPT/CHKPT parameter instructs MFX to take a checkpoint at every end-of-volume of a SORTOUT data set when OUTFIL is not used and also at the beginning of Phase 3 before the SORTOUT data set is opened. Either spelling of this parameter is accepted.
This parameter requires a SORTCKPT DD statement. It cannot be specified in conjunction with a user-issued STIMER macro or an incore sort. Checkpoints cannot be taken within a user exit routine.
Refer to Performance Considerations for an explanation of the Checkpoint/Restart feature.