Start of change CICS VSAM Transparency for z/OS, Version 1.2


Operational considerations for DMF

When CICS VT detects a difference, the application program abends. Ensure that the data in DB2 and in VSAM is synchronized. Otherwise, DMF might report errors that are due to data differences as opposed to potential problems with CICS VT or user exits.

If you are using DMF with a batch program that updates data, any abend is likely to result in unsynchronized data. This is because DB2 forces updates to the migrated data set to be rolled back, whereas the original VSAM data remains partially updated. It is essential that you are aware of this and take the appropriate steps to resynchronize the data following an abend. This could mean that you need to take a backup of the original VSAM data set prior to running an update program with DMF enabled.

If the program is read-only, data recovery following an abnormal termination is not required.

DMF in CICS and batch opens the original VSAM data set. This means that you will encounter sharing issues if you try to use DMF in CICS and batch concurrently. If you make a copy of the original VSAM, you can concurrently test read-only programs. Programs that perform updates cannot be tested concurrently.



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Last updated: December 6, 2013 20:43:9

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Timestamp icon Last updated: Friday, 6 December 2013


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