Tuxedo as a Transaction Processing Monitor › Failure Handling

Failure Handling

In CA Gen, there are two distinct methods for handling the failure of a PStep. The failure can be treated either as an abend or a rollback. If the situation is treated as a rollback, the export view is returned and the PStep that fails does not force the calling PStep to abend. If the failure is treated as an abend, there are a minimum of four scenarios that may cause the condition to occur:

• An Application PStep sets an Exit State of ABORT
• Communications failure
• Unhandled database (DBMS) error
• The application issues an Abort Transaction action language statement

If an abend occurs, the trace view is returned to the calling PStep. The trace view contains an XFAL buffer message, so that, if PStep2 fails, the resulting XFAL message causes PStep1 to fail as well.

By using the following action statement, abend scenario 3 can be processed as a rollback. This change gives control to the application instead of the runtime handling the abend.

WHEN DBMS ERROR
EXIT STATE is ROLLBACK
ESCAPE

When an abend occurs, the invoking server is notified of the failure and control is given to SRVRERROR() that is the server error exit. This exit allows viewing of the contents of the XFAL message, and to amend it if necessary.