Updating runtime resource and descriptor definitions

When dynamic resource definition (DRD) is enabled, you can update runtime resource and descriptor definitions dynamically, eliminating the need to use the online change process or to cold start IMS™. Although the overall process for updating runtime database, application program, transaction, and routing code definitions is the same, there are minor variations in the steps you complete.

When DRD is enabled for MODBLKS resources, runtime resources can be updated by:

Importing the stored resource definitions from the resource definition data set (RDDS) by using the IMPORT DEFN SOURCE(RDDS) command.
Importing the stored resource definitions from the IMSRSC repository by using the IMPORT DEFN SOURCE(REPO) command.
Using the appropriate UPDATE command (according to the type of resource definition you want to update).

When DRD is enabled for MODBLKS resources, runtime descriptor definitions can be updated by:

Importing the stored descriptor definitions from the RDDS by using the IMPORT DEFN SOURCE(RDDS) command.
Importing the stored descriptor definitions from the repository by using the IMPORT DEFN SOURCE(REPO) command.
Using the appropriate UPDATE command (according to the type of descriptor definition you want to update).

Start of change The changes that you make to resource and descriptor definitions by using the UPDATE and IMPORT commands exist during the current execution of the IMS system and are recoverable across a warm or emergency restart. IMS uses change lists to preserve the changes across a warm or emergency restart. To preserve the changes across a cold start, export the updated definitions to an RDDS or the repository before IMS terminates, and then import the stored definitions from the RDDS or repository back into IMS either during cold start processing (by using the automatic import function), or when IMS is up and running (by using the IMPORT DEFN command). End of change

If the attributes specified on the UPDATE command are already defined for the resource:

No update is made
No resources are quiesced
No log record is created
A completion code of zero is returned

By taking no action, IMS avoids unnecessary processor usage.

Unlike the online change process where either all resource definitions are updated or no resource definitions are updated, each resource or descriptor definition can be updated individually.