FILSZ indicates the actual (FILSZ=n) or estimated (FILSZ=En) decimal number of records to be sorted, taking into account all record additions and deletions due to an E14 or E15 exit routine, the INCLUDE/OMIT control statement, the SUM or DUPKEYS control statement and the SKIPREC and STOPAFT parameters.
FILSZ=n instructs MFX to terminate with an error message unless exactly n records are to be sorted. Since the number of records deleted by SUM or DUPKEYS processing in Phase 1 is indeterminate and may not be reproducible, much less predictable, only the estimated En value should be used if a SUM or DUPKEYS control statement is present.
The FILSZ option can also be specified on the SORT control statement. The specification in the PARM field will take precedence over that on the control statement.