Lock Management › Physical Area Locks

Physical Area Locks

CA IDMS/DB maintains a physical area lock as a flag within the first space management page of an area. It examines and sets the lock whenever the area is opened for update. This occurs when:

• A local mode transaction readies the area in an update mode
• A DC/UCF system is started in which the area status in the DMCL is UPDATE
• A DCMT VARY AREA command changes the status of the area to UPDATE

Unlocking the Physical Area

Once a physical lock is placed on an area, it remains set until:

• The local mode transaction or central version terminates normally
• Manual recovery procedures are used to roll out the effects of a failing local mode transaction
• A central version is restarted after an abnormal termination and subsequently shutdown normally
• The area status within central version is changed from update to another status

Physical Area Locks and Shared Areas

In a data sharing environment, the physical area lock in a shared area is set by the first member of a data sharing group to open the area for update and it is reset by the last member to relinquish control.