IMS catalog and HALDB alter

When you alter a HALDB database in an IMS-managed ACBs environment, IMS reads the ACB members that are in the staging data set of the IMS catalog. The ACB members define the new structure of the database. These ACB members must be maintained in the staging data set of the IMS catalog until the ALTER IN PROGRESS status is cleared from the database partition records in the RECON data set.

If the ACB members for the altered database are modified or deleted from the IMS catalog while the partition records have an ALTER IN PROGRESS status, application programs and utilities cannot access the database and IMS cannot activate the new database structure when you issue the IMS type-2 IMPORT DEFN SOURCE(CATALOG) command. If the ACB members are modified or deleted, you can restore access to the database and activate the database changes by restoring the staging data set of the IMS catalog to its state at the time that alter processing began.

Unless database versioning is enabled to allow certain application programs to continue accessing the database without modifications, you must also activate application programs that reference the altered segments in the database when you activate the new ACB members.