Lock Management › Readying Areas › Central Version Area Status

Central Version Area Status

Area Status and Ready Modes

Each area accessible from within a central version has a status associated with it. The status of an area affects the mode in which transactions executing under the central version can ready the area:

Establishing the Area Status

The status of an area within a central version is initially established by specifications made within the DMCL used by the DC/UCF system. An area's status may subsequently be changed by DCMT commands.

Permanent Area Status

When an area's status is changed through a DCMT command, it may be designated as permanent. A permanent area status persists across both normal and abnormal system terminations until it is subsequently changed by another DCMT command or until the journal files associated with the central version are initialized. Whether an area's status has been designated as permanent is indicated on the output from a DCMT DISPLAY AREA command.

At System Startup

If a permanent area status is not in effect, the first time a system is started and each time it is subsequently started after a normal shutdown, the status of the area is set to that specified in the ON STARTUP parameter of the ADD SEGMENT or ADD AREA statement within the DMCL definition. The default area status is UPDATE.

Following an Abnormal System Termination

If a permanent area status is not in effect, when restarting a system following an abnormal termination, the status of the area is set to that specified in the ON WARMSTART parameter of the ADD SEGMENT, or ADD AREA statement within the DMCL definition. The area can be set to what it was at the time of the failure (the default) or it can be set to an explicit value.

Changing Area Status

You can change the status of an area within a central version by issuing a DCMT VARY AREA or VARY SEGMENT command. In certain cases, CA IDMS cannot change the status of the area immediately because existing transactions are accessing the area. In addition to active transactions, longterm or notify locks held by pseudo-conversational applications may prevent the area status from being changed. If CA IDMS cannot change the status immediately, it initiates an internal task that completes the DCMT VARY operation when no more conflicts exist. During the time it takes to complete the vary, transactions attempting to ready the area in a mode that is incompatible with the new area status receive an error.

Note: For more information about the DCMT VARY AREA and VARY SEGMENT commands, see the CA IDMS System Tasks and Operator Commands Guide.