The benefits that DBCTL offers in the area of system availability are:
You do not need to regenerate the DBCTL interface every time you upgrade your CICS® or IMS™ system.
With DBCTL, sharing of databases between multiple CICS systems is improved. CICS systems in the same MVS™ image can share databases with other CICS systems, with batch (as BMPs), and with IMS TM without the need for IMS data sharing. Performance with DBCTL is better than using CICS database-owning regions (DORs) with multiregion operation.
The interface is designed so that a failure in CICS should not cause DBCTL to fail, and a failure in DBCTL should not cause CICS to fail.
CICS and DBCTL are independent of each other; that is, CICS can be running while DBCTL is not, and vice versa. A CICS transaction, CDBC, is provided for you to connect to, and disconnect from, DBCTL dynamically. Another CICS transaction, CDBI, enables you to inquire on the status of the connection.
DBCTL enables you to do a number of operations online, including:
These utilities are summarized below, see IMS database utilities for more information.
The online image copy utility is used to create an as-is copy of your database while it is being updated. The copy can then be used for recovery purposes. This utility is used for HISAM, HDAM, and HIDAM databases only.
In many installations, it is important for the online system to be is available to users for most of the day. The online change utility enables you to update ACBLIBs, which contain PSBs and data management blocks (DMBs), and security information belonging to full function databases, without bringing down the system. For guidance information on this utility, see the IMS System Administration Guide or the IMS Administration Guide: System and the IMS Utilities Reference: Database manual manual.
As mentioned in Access to data entry databases (DEDBs), the DEDB direct reorganization utility enables you to reorganize DEDBs without taking them offline.
DBCTL users can use CICS or IMS support for the extended recovery facility (XRF) in either of the following ways:
See Recovery and restart operations for DBCTL for more information.