Overview of resource activation when IMS manages ACBs

A database resource is considered activated when the ACB for the resource is imported into the IMS directory data set and the resource is loaded into memory by the online systems or will be the next time an online system schedules the resource. However, before you can use an activated database resource, you might need to take more steps. For example, for new databases, you might need to allocate database data sets, define the database in the RECON data set, initialize the database, or identify the database or program to the online system with the IMS type-2 command CREATE DB or CREATE PGM command. For a modified database, you might need to reorganize the database.

If you are using DDL CREATE statements to define a new database, IMS can activate the database automatically if AUTOCREATE=YES or AUTOIMPORT(CREATE) is specified in the <CATALOG> section of the DFSDFxxx PROCLIB member. If you are creating a DEDB database by using DDL, you can specify options for the automatic allocation of a DEDB area data set in the <DDL> section of the DFSDFxxx PROCLIB member.

If you define and generate your database resources by using the IMS generation utilities and submit your resources to IMS by using either the ACB Generation and Catalog Populate utility (DFS3UACB) or the IMS Catalog Populate utility (DFS3PU00), most resources cannot be activated automatically if any online systems are using the IMS catalog. DOPT PSBs can be activated automatically if your z/OS system supports extended sharing of PDSE data sets and you specify the MANAGEDACBS=(UPDATE,SHARE) when you run either of the Populate utilities.

Whether you use DDL or either of the Populate utilities, resources that are not activated immediately are stored in the staging data set of the IMS catalog, where they wait in a pending state until they are activated by issuing the IMPORT DEFN SOURCE(CATALOG) command.

Before you activate your resources, make sure that all of the prerequisite steps for activation are complete or at least planned for.

Whether IMS activates the resources automatically upon receiving DDL statements or later when you issue the IMPORT DEFN SOURCE(CATALOG) command, IMS uses the same internal import process to update the resources to the IMS directory data sets and to the online memory of all participating IMS systems. The internal import process that IMS uses is similar to the manual Online Change process that must be used to activate resources in online IMS systems that use ACB, DBD, and PSB libraries to manage ACBs.

This internal import process includes several prepare and commit phases that are equivalent to the prepare and commit phases of the online change function.

To determine the status of IMS import processing, especially if errors occur during activation, issue the QUERY MEMBER TYPE(IMS) SHOW(STATUS) command.

If the IMS catalog is shared by multiple IMS systems, see Activation when the IMS catalog is shared.