Recovering from subsystem termination

You can recover Db2 after Db2 or an operator-issued cancel causes the subsystem to terminate.

Symptoms

When a Db2 subsystem terminates, the specific failure is identified in one or messages. The following messages might be issued at the z/OS® console: 

DSNV086E - DB2 ABNORMAL TERMINATION REASON=XXXXXXXX 
DSN3104I - DSN3EC00 -TERMINATION COMPLETE 
DSN3100I - DSN3EC00 - SUBSYSTEM ssnm READY FOR -START COMMAND

The following message might be issued to the IMS master terminal: 

DSNM002I   IMS/TM xxxx DISCONNECTED FROM SUBSYSTEM
      yyyy RC=rc

The following message might be issued to the CICS® transient data error destination, which is defined in the RDO: 

DSNC2025I  - THE ATTACHMENT FACILITY IS INACTIVE

Environment

  • IMS and CICS continue.
  • In-process IMS and CICS applications receive SQLCODE -923 (SQLSTATE '57015') when accessing Db2.

    In most cases, if an IMS or CICS application program is running when a -923 SQLCODE is returned, an abend occurs. This is because the application program generally terminates when it receives a -923 SQLCODE. To terminate, some synchronization processing occurs (such as a commit). If Db2 is not operational when synchronization processing is attempted by an application program, the application program abends. In-process applications can abend with an abend code X'04F'.

  • IMS applications that begin to run after subsystem termination begins are handled according to the error options.
    • For option R, SQL return code -923 is sent to the application, and IMS pseudo abends.
    • For option Q, the message is enqueued again, and the transaction abends.
    • For option A, the message is discarded, and the transaction abends.
  • CICS applications that begin to run after subsystem termination begins are handled as follows:
    • If the CICS attachment facility has not terminated, the application receives a -923 SQLCODE.
    • If the CICS attachment facility has terminated, the application abends (code AEY9).

Resolving the problem

Operator response:
  1. Restart Db2 by issuing the command START DB2.
  2. For IMS environments, re-establish the IMS connection by issuing the IMS command /START SUBSYS DB2.
  3. For CICS environments, re-establish the CICS connection by issuing the CICS attachment facility command DSNC STRT.