Online activation of new and changed database resources when IMS manages ACBs

For IMS systems that manage ACBs, the IMPORT DEFN SOURCE(CATALOG) command performs a function that is equivalent to the function that the online change process performs for IMS systems that use ACB libraries. In fact, internally the IMPORT DEFN SOURCE(CATALOG) uses a similar phased process to import the modified ACBs from the staging data set of the IMS catalog to the directory data set of the IMS catalog.

Depending on the type of changes you are making and whether you are adding new resources or modifying existing resources, additional steps might be required before or after you issue the IMPORT DEFN SOURCE(CATALOG). For example, if you are modifying the structure of an existing database, you might need to unload and reload the database before you activate ACB that contains the modified structure. Or if you are introducing a new database into an IMS system, you might need to allocate data sets or define the runtime attributes of the database by using either the CREATE DATABASE command or the DATABASE stage-1 system definition macro. In some cases, IMS might perform the some of these prerequisite steps for you.

If you are using DDL to create a new Fast Path DEDB database, you can configure IMS to create the area data sets for you automatically by specifying AUTOCREATE=YES in the catalog section of the DFSDFxxx PROCLIB member and specifying the attributes of the area data sets in the DDL section of the DFSDFxxx member.

If you are altering PSBs only, you can stage the activation of the PSBs across subsets of IMS systems that share the ACBs in an IMSplex by specifying OPTION(UPDATEPSB) FOR(IMSID(imsid)) on the IMPORT DEFN SOURCE(CATALOG) command.

Before issuing the IMPORT DEFN SOURCE(CATALOG), resources that will be affected by the change must be stopped.