DEDB Alter utility enhancements

In IMS 15, the DEDB Alter utility is enhanced to enable you to add a new field to existing free space in a segment while the DEDB area remains online.

This enhancement increases the availability of your DEDB database. Previously, a DEDB database had to be taken offline to add a new field to a segment.

Requirements:
  • The randomizer must either be a genuine two-stage randomizer defined as one in the DBD or, optionally, a one-stage randomizer defined as one in the DBD, if the DEDB has only one area.
  • All IMS data sharing systems must be at IMS 15 or later.
  • The DEDB databases must be registered to DBRC.
  • 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.
  • if you expand just the SDEP portion of an area by increasing the shadow’s data set size, you will still need to do an ACBGEN.
Restrictions:
  • You can alter only one area in a DEDB database at a time with the DEDB Alter utility. You can have multiple instances of the DEDB Alter utility running concurrently, but each instance must be running against a different DEDB database.
  • The DEDB Alter function does not support DEDB databases that are in Virtual Storage Option (VSO) or Shared Virtual Storage Option (SVSO) mode. DEDB databases with the VSO or SVSO option must first be unloaded with the /VUNLOAD command before running the DEDB Alter utility.
  • Because the IMS management of ACBs does not support XRF environments, the DEDB Alter utility does not support XRF when IMS manages ACBs.

Migration considerations

If you are invoking the DEDB Alter utility for an IMS 15 function, such as ALTERDB, the DEDB Alter utility detects the version of the IMS system and terminates if the IMS version does not support the particular change.

Coexistence considerations

You can run the DEDB Alter utility in a coexistence environment; however, if you are invoking the DEDB Alter utility for an IMS 15 function such as ALTERDB, the DEDB Alter utility detects the version of the IMS system and terminates if the IMS version does not support the particular change.

Changes to administering IMS

For a list of topics for administering IMS, that are changed for this enhancement, see the Database administration and System administration rows in the table in Documentation changes.

Changes to troubleshooting for IMS

For a list of the messages and codes that are new or changed for this enhancement, see the IMS messages and codes row in the table in Documentation changes.

For a complete list of all of the new, changed, and deleted messages, and abend codes in IMS 15, see Message and code changes in IMS 15.

Changes to utilities

For a list of the utilities that are changed for this enhancement see the Database utilities row in the table in Documentation changes.

Documentation changes

The following table lists the publications that contain new or changed topics for the DEDB Alter utility enhancements. Publications that are not impacted by this enhancement are not included in the table.

Table 1. Links to topics that have new or changed content for this enhancement
Publication Links to topics
Release planning
Database administration
IMS messages and codes DFS messages
Database utilities