PI84441: A SUB THAT HAS BOTH SOURCE AND TARGET IN THE SAME INSTANCE OF IIDR Z/OS(LOOP BACK) CAN PREVENT A NORM SHUTDOWN OF DB2.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• A looped back subscription is susceptible to a timing situation
  where the source and target are both ending because DB2 has been
   directed to perform a normal shut down.  As they proceed
  through the exchange of data at subscription end, the absence of
   DB2 at the target side causes the exchange to fail, and both
  sides remain active indefinitely.  The source side continues to
  maintain its connection to DB2, which prevents DB2 from
  completing the normal shut down.
  

Local fix

• End any "looped back" subscriptions before shutting down DB2.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of IIDR CDC for z/OS who use "looped   *
  *                 back" subscriptions.                         *
  ****************************************************************
  * PROBLEM DESCRIPTION: If a subscription is "looped back",     *
  *                      that is it has both the source and      *
  *                      target sides of the subscription in the *
  *                      same instance of IIDR CDC for z/OS,     *
  *                      then, if DB2 is being shut down, the    *
  *                      subscription will fail in its ending    *
  *                      exchange between the source and target, *
  *                      due to the lack of DB2 at both sides of *
  *                      the subscription.  Each side will then  *
  *                      stall, waiting on the other, and the    *
  *                      IIDR CDC for z/OS address space will    *
  *                      not close all its DB2 connections.      *
  *                      This will cause DB2 to remain up until  *
  *                      a STOP MODE(FORCE) is issued to bring   *
  *                      DB2 down.                               *
  ****************************************************************
  * RECOMMENDATION: APPLY CORRECTIVE SERVICE                     *
  ****************************************************************
  
  A "looped back" subscription can cause DB2 to not shut down
  until a STOP MODE(FORCE) is issued.
  

Problem conclusion

• Logic to handle the source-target exchanges when a subscription
  is ending has been ammended to proceed properly even if the DB2
  subsystem is no longer available.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UI48976

Modules/Macros

•    CHCSCTGP CHCSCTPF CHCTCTGP CHCTCTPF
  

Fix information

• Fixed component name

  INFO SRVR CDC Z

• Fixed component ID

  5655U7600

Applicable component levels

• RA21 PSY UI48976

     UP17/07/27 P F707

Fix is available

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