PI10774: 0C4-0000003B DSNX8LLM.DSNX8STO+1332

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• IDAA defects 170176 d170176 pi10774 dpi10774
  Abend 0C4-0000003B DSNX8LLM.DSNX8STO+1332 during Stop
  Accelerator command processing.
  ***************************************************************
  Additional Symptoms and Keywords
   ABEND0C4 AB0C4 S00C4 0C4
    0C4-0000003B 0000003B RC0000003B
     DSNX8STO DSNX8STO+13321332 OFFSET1332
    0C4-00000011 00000011 RC00000011
     DSNVSRX +2124 +2124 OFFSET2124
   ABEND04E AB04E S004E 04E
    04E-00C200A3 00C200A3 RC00C200A3
     DSNIDM DSNB5COM+2F5E DSNB5COM +2F5E 2F5E OFFSET2F5E
   IDAAV2R1/K IDAAV3R1/K IDAAV4R1/K IDAA
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 10/11 for z/OS users who use         *
  *                 IBM DB2 Analytics Accelerator (IDAA).        *
  ****************************************************************
  * PROBLEM DESCRIPTION: Unpredictable results including         *
  *                      intermittent abend 0C4-0000003B         *
  *                      DSNX8LLM.DSNX8STO+1332 during Stop      *
  *                      Accelerator command processing.         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  A remote application connects to a DB2 for z/OS server and
  executes queries that qualify to be off-loaded to IDAA.  Due to
  the IDAA involvement, the DBAT that services the query must
  remain active.  That is, at the end of a transaction, DB2
  cannot allow the connection environment to be inactivated away
  from the DBAT.
  However, if the transaction ends as a result of a rollback,
  this inactivation is incorrectly allowed and the DBAT is
  therefore incorrectly pooled so it can be used to service
  other work.  This can lead to unpredictable results because
  Accelerator related structures can now refer to, either,
  threads that service applications that have never utilized an
  accelerator or threads that no longer exist.
  

Problem conclusion

• When a DBAT has been used to service SQL that utilizes an
  accelerator, DB2 has been changed to prevent the DBAT from
  being pooled after a rollback.
  WARNING WARNING WARNING
  Users should be aware that there MAY be operational issues as
  a result of this change because more remote application
  environments will have to stay active, after rollback
  processing, IF the application executes SQL that can be
  off-loaded to an accelerator.
  Basically, the operational impact of this change occurs as a
  result of requiring an increased number of DB2 threads (DBATs)
  and remote client system network connections (to the DB2
  server) in order to service the same amount of remote
  application work.
  Possible symptoms may include:
  . Increased storage utilization symptoms due to additional
    threads (DBATs) that may now be required.
  . Performance degradation, perhaps due to the queuing that may
    occur as a result of reaching or approaching the MAXDBAT
    resource limit.
  . High rate of unexpected "Idle Thread Time-out" conditions
    (message DSNL030I with reason code 00D3003B) that may result
    in unexpected remote application failures.
  . Remote client "connection concentrator" environments may also
    be adversely affected as a result of their inability to pool
    connections on a transaction (rollback) boundary.
  Any potential exposure to these symptoms only occurs with
  respect to remote applications that access DB2, as a server,
  and then utilize an accelerator AND issue rollback.  The
  rollback has an effect even if it is executed after accelerator
  access is complete.  Since exposure is based on the execution
  of a rollback, which is not typical, it is unlikely that users
  will be affected, but it is possible.
  After applying this change, users should monitor their system
  for these symptoms.  The symptoms may be normal under the
  circumstances and measures may be necessary to address the
  condition.
  

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:

  UI15443 UI15444

Modules/Macros

• DSNLXREL
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RA10 PSY UI15443

     UP14/03/12 P F403

• RB10 PSY UI15444

     UP14/03/12 P F403

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.