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Preserving your CL/Supersession Table Database

Technical Blog Post


Preserving your CL/Supersession Table Database



The most vital element of your CL/Supersession environment is your Table Database, or TDB. This is where all profiles are stored. These profiles contain all of your user, group, and global menu customizations, including the ordering of available sessions, initial dialogs, triggers, and logmode selections.


In support, sometimes we see trouble with the TDB. There are a few things that you can do that will reduce your exposure to TDB woes.


First and foremost, make periodic backups. If you recycle on a regular schedule, the perfect time to make a backup is when your system is down. If your users have the ability to highly customize their menu, you may want to do so often.


Second, consider a REORG to reduce fragmentation if you delete or change many profiles at once. If you need more space, you can REPRO a copy of your TDB, then delete and reallocate a new, larger one.


Third, do not use the SPANNED parameter in the allocation of the TDB. We see far more problems with SPANNED record TDBs than without. We have a support technote that describes how to convert your TDB from a SPANNED format to non-spanned, see technote 1648954.


If you're in the unfortunate circumstance of having a corrupt TDB, there may be a solution.


If you suspect that a control record is corrupt, you may be able to restore your TDB by doing the following:

  1. REPRO your existing TDB.
  2. Allocate a new, empty TDB.
  3. Start the CL/Supersession address space pointing to the new, empty file.
    - This will create a control record in the new TDB
  4. Stop the address space.
  5. REPRO the TDB with a missing/corrupt control record to the new TDB.


If you have another corrupt record, deleting just that record might get you past the trouble. For all releases of CL/SuperSession, the KLVTBULD utility (previously KLSTBUNL for V1.4.7), which unloads the TDB to a partitioned dataset, may help figure out which, if any, records are affected. This utility is described in Chapter 15 of both the CL/SuperSession 2.1 Customization Guide and CL/Supersession 1.4.7  Customization Guide.


Hopefully these suggestions will keep your TDB running smoothly!



title image (modified) credit: (cc) Some rights reserved by hatalar205


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