January 26, 2010

Potential Data-Corruption Issues Cited in Red Alerts

IBM's DB2 for z/OS team has been busy lately. I've received two Red Alert notices this month. 

The most recent alert, released Jan. 21, concerns the coupling facility (CF). If CF fails and restarts before cleanup is completed, data could be corrupted.

From the alert:

"When a CF terminates, the structures on the CF are physically deleted and duplex structures will fail over to the other instance of the structure and simplex structures will rebuild into a new instance of the structure."

In a Jan. 12 Red Alert, IBM informed customers of a potential data-corruption issue with the CATMAINT UPDATE SCHEMA SWITCH utility, which is new with DB2 Version 9.

From the alert:

"After running the CATMAINT UPDATE SCHEMA SWITCH utility, object's DBDs were corrupted, causing various overlay type ABENDs when accessing the row. This problem only affects databases that contain tables that have columns with user defined default values."

IBM Red Alerts is a no-charge service that provides technical information for IT professionals who maintain mainframes. By registering at, you'll receive e-mail notification of new support bulletins.

To subscribe or view recent mainframe-specific Red Alerts, go here.