🔍 Comparing Datasets with ISRSUPC (SuperC) in JCL: Filtering Delta Records
In mainframe environments, comparing datasets to identify changes is a common task — especially in data migration, auditing, or version control scenarios. IBM’s ISRSUPC utility, also known as SuperC, provides a powerful way to perform line-by-line comparisons and extract delta records.
🧰 What is ISRSUPC?
ISRSUPC is a batch utility that performs comparisons between two datasets or members. It’s part of the ISPF suite and is often used interactively via ISPF Option 3.13, but it can also be run in batch using JCL.
✅ Use Case: Filtering Delta Records
Suppose you have two datasets:
- OLD.DATASET — the original version
- NEW.DATASET — the updated version
You want to extract only the changed lines (delta records) between them. Here’s how you can do it.
📄 Sample JCL to Extract Delta Records
- //COMPARE EXEC PGM=ISRSUPC,PARM=(‘LINECMP,DELTAL,UPDPDEL‘)
- //NEWDD DD DSN=NEW.DATASET,DISP=SHR
- //OLDDD DD DSN=OLD.DATASET,DISP=SHR
- //OUTDD DD SYSOUT=*
- //DELDD DD DSN=DELTA.OUTPUT.DATASET,DISP=(NEW,CATLG,DELETE),
- // SPACE=(TRK,(1,1)),UNIT=SYSDA
- //SYSIN DD *
- CMPCOLM 1:80
- /*
- //
🔍 Explanation of Parameters
- LINECMP: Compares datasets line-by-line.
- DELTAL: Produces a delta listing — only the changed lines.
- UPDPDEL: Ensures full changed lines are written to the DELDD dataset.
- CMPCOLM 1:80: Specifies the column range to compare (adjust as needed).