Deleting runtime resource and descriptor definitions

When dynamic resource definition (DRD) is enabled, you can use the DELETE command to delete runtime resource and descriptor definitions dynamically, eliminating the requirement to use the online change process or to cold start IMS. Although the overall process for deleting runtime database, application program, transaction, routing code, MSC physical link, MSC logical link, MSC MSNAME, and MSC remote LTERM definitions is the same, there are minor variations in the steps you complete.

The resource and descriptor definitions that you delete dynamically using the DELETE command remain deleted across a warm or emergency restart.

Each resource or descriptor definition is deleted individually, unlike the online change process, where either all resources or descriptor definitions are deleted or no resources or descriptor definitions are deleted.

Deleting runtime resource and descriptor definitions when using an IMSRSC repository

To delete runtime resource and descriptor definitions from IMS and from the IMSRSC repository, perform the following procedure:
  1. Issue the DELETE command locally at each IMS that contains the runtime definitions.

    If definitions of more than one type are being deleted, issue multiple different DELETE commands (according to the type of resource or descriptor definitions you want to delete).

  2. Issue the DELETE DEFN command to delete the definitions from the repository.

    Issuing the command ensures that the definitions remain deleted in IMS across a cold start, and that they are not imported from the repository during cold start processing or with the IMPORT DEFN command.

    If using an XRF (Extended Recovery Facility) configuration, issue the DELETE DEFN command with the IMS IDs of both the active and alternate system on the FOR(IMSID()) keyword.

The transactions and routing codes must be deleted before the programs can be deleted.

All the definitions for the names specified on the DELETE DEFN command are deleted as a single unit of work.

Recommendation: When a resource definition is being deleted in the IMSplex, delete the runtime resource first and then delete it from the repository.

Unlike the process for deleting runtime resource and descriptor definitions when using an RDDS, issuing the EXPORT command does not ensure that the resources remain deleted in IMS across a cold start.

Deleting runtime resource and descriptor definitions when using an RDDS

To delete runtime resource and descriptor definitions from IMS and from an RDDS, perform the following procedure:
  1. Issue the DELETE command locally at each IMS that contains the runtime definitions.

    If definitions of more than one type are being deleted, issue multiple different DELETE commands (according to the type of resource or descriptor definitions you want to delete).

    If you have set up automatic export to an RDDS, automatic export occurs at system checkpoint and removes the deleted definitions from the system RDDS.

  2. If you have not set up automatic export to an RDDS, issue the EXPORT command at each IMS from which the definitions were deleted to ensure the removal of deleted definitions from the system RDDS (or non-system RDDS).
You can then import the resource and descriptor definitions from the RDDS back into IMS in one of the following ways:
  • During cold start processing by using the automatic import function.
  • After IMS is up and running by using the IMPORT DEFN command.

Restrictions

You cannot delete a runtime resource definition if the resource is in use. Examples of resources in use include:

  • A database that is being accessed by an application program
  • A database that is referenced by the program specification block (PSB) for an existing program
  • A /STOP or UPDATE command that is in progress for the resource
  • An application program that is scheduled to run
  • An active routing code
  • A transaction with messages queued for it
  • A transaction that has any work in progress
  • An MSC physical link, logical link, or logical link path (MSNAME) that is not stopped
  • An MSC remote LTERM that is not stopped
  • An MSC physical link that is referenced by an MSC logical link
  • An MSC logical link that is referenced by an MSC MSNAME
  • An MSC MSNAME that is referenced by an MSC remote LTERM

If you attempt to delete a resource that is in use, the delete attempt fails. In a sysplex environment, the delete attempt might succeed on some IMS systems and fail on others.

You cannot delete the following resources that are supplied by IMS: DBFDSRT1, DFSDSDB1, DFSDSPG1, DFSDSTR1, and DBF#FPU0.

You cannot delete a HALDB master database resource unless it has no partitions defined and you have issued a /DBRECOVERY command for the database.