Replacing an active DEDB database randomizer online with the DEDB Alter utility

You can replace an active DEDB database randomizer while the DEDB database remains accessible online by using the REPLRAND function of the DEDB Alter utility (DBFUDA00). The DEDB Alter utility's randomizer change supports DEDB databases with and without SDEP segments defined.

1. Prepare for replacing the DEDB randomizer online
   1. Assemble and link-edit the changed randomizer into the IMS SDFSRESL or one of the libraries of the IMS SDFSRESL STEPLIB concatenation.
   2. If you are adding a Segment Edit/Compression exit routine, assemble and link-edit the Segment Edit/Compression exit routine into the IMS SDFSRESL or one of the libraries of the IMS SDFSRESL STEPLIB concatenation.

      If you are using the DEDB Alter utility to add a Segment Edit/Compression exit routine, the Segment Edit/Compression exit routine must be able to handle mixed compressed and non-compressed data in a DEDB database. If data is non-compressed, on read access, it does not expand the non-compressed data, and on write access, it compresses the data and writes out as compressed data. If data is compressed, on read access, it expands the compressed data, and on write access, it compresses the data and writes out as compressed data.

   3. Alter the RMNAME parameter with a different two-stage DEDB randomizer name (or one-stage randomizer name if the DEDB database contains only one area) for the DEDB database associated with the active DEDB area to be altered in the DEDB DBD definitions.
      • If you use the DBDGEN utility, alter the RMNAME parameter on the DBD statement.
      • If you use DDL, alter the RMNAME parameter on the ALTER DATABASE statement.
   4. If you are adding one or more fields to existing free space that is in a segment of an active DEDB area, use one of the following methods to add the fields:
      • If you use the DBDGEN utility, add one or more FIELD statements under the SEGM statement of the segment that you are altering.
      • If you use DDL, use the ALTER TABLE statement with the INTERNALNAME parameter.
   5. If you are adding a Segment Edit/Compression exit routine, perform one of the following options:
      • If you use the DBDGEN utility, add the COMPRTN parameter on the SEGM statement.
      • If you use DDL, add the EDITPROC parameter on the ALTER TABLE statement.
   6. If you are adding a Segment Edit/Compression exit routine, update the DEDB DBD definitions to include the routine.
      • If you use the generation utilities, update the COMPRTN parameter on the SEGM statement in the DBDGEN utility.
      • If you use DDL, update the EDITPROC parameter on the ALTER TABLE statement.
   7. If you use the IMS generation utilities, run the DBDGEN utility with the new and updated parameters on the DBD statement in the DEDB DBD definitions.
   8. If you use generation utilities, run the ACBGEN utility for all PSBs that reference the changed DEDB DBD definitions to the staging ACBLIB.
   9. If ACBMGMT=CATALOG is specified in the DFSDFxxx member of the IMS PROCLIB data set, populate the new DEDB DBD definitions to the IMS catalog by using one of the following methods:
      • By using the staging ACBLIB that you created in step 1.h as input, run the IMS Catalog Populate utility (DFS3PU00) and use the MANAGEDACBS statement with the STAGE parameter.
      • Use DDL.
2. Run the DEDB Alter utility using the REPLRAND function to replace a randomizer while the DEDB database remains accessible online.

   If you are adding a Segment Edit/Compression exit routine, during DEDB Alter utility execution the new Segment Edit/Compression exit is not invoked for any areas. The Segment Edit/Compression exit routine is not enabled during DEDB Alter processing. Instead, it is enabled for all DEDB areas after successful DEDB Alter utility completion.

3. If you are using the IMS Catalog, use one the following methods to update it after the DEDB Alter utility finishes:
   • Run both the ACB Maintenance utility and the IMS Catalog Populate utility (DFS3PU00).
   • Run the IMS Catalog ACBGEN utility (DFS3UACB), which builds the ACBs and populates the IMS Catalog in a single job step.