When MAXSORT includes an exit routine or is invoked from a program, it cannot be restarted from a breakpoint. Instead, it can be restarted from a checkpoint using the standard OS/VS Checkpoint-Restart feature. Checkpoints are taken at the end of each intermediate sort or merge.
When MAXSORT is restarted from a checkpoint, modified PARM options cannot be specified on the EXEC statement. Only the CORE parameter can be passed through $ORTPARM.
To specify that checkpoints be taken for a MAXSORT with an exit routine or for an invoked MAXSORT, the following rules must be observed:
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Include the SORTCKPT DD statement in the JCL (in addition to the SORTBKPT DD statement.
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Assign a permanent data set name to every SORTWKnn DD statement and specify DISP=(NEW,DELETE,KEEP).
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Specify RD=R and MSGLEVEL=1 on the JOB statement.
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Specify the CKPT parameter on the SORT/MERGE control statement.