PM79545: ABEND0C4 AT DSNX9CAC OR DSNX9TNE WHEN STOPPING DB2 AFTER CANCELING UDF WORKLOADS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• After soft-cancelling a thread that uses external UDFs , a
  subsequent STOP DB2 or STOP DB2 MODE(FORCE) action may result in
  ABEND0C4 in DSNX9CAC or DSNX9TNE at various offsets within the
  modules. It is also possible for STOP DB2 to hang while
  attempting to stop the WLM stored procedure address spaces.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 users of external User Defined       *
  *                 Functions ( UDF )                            *
  ****************************************************************
  * PROBLEM DESCRIPTION: After a DB2 cancel or MVS cancel or an  *
  *                      abend of a thread that invokes external *
  *                      UDFs from within stored procedures,     *
  *                      the following symptoms may occur:       *
  *                      1. an MVS command to either refresh or  *
  *                         to quiesce the WLM environment       *
  *                         issues message IWM031I but does not  *
  *                         complete                             *
  *                      2. a STOP DB2 command issues message    *
  *                         DSNX922I but then hangs and does not *
  *                         complete                             *
  *                      3. a STOP DB2 MODE(FORCE) command hits  *
  *                         ABEND0C4 RC00000010 RC00000011       *
  *                         RC00000038 at various offsets in     *
  *                         DSNX9CAC or DSNX9TNE                 *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Missing code in DB2 recovery code paths caused a cancelled
  or abended thread to incorrectly skip clean up of WLM-related
  resources for UDFs that are invoked from within stored
  procedure instances. Stored procedure instances can occur
  when an application repeatedly calls a stored procedure
  that returns result sets but does not close the result sets
  before the next procedure call.
                                                                .
  As a result, the WLM-related resources were orphaned by the
  cancelled / abending thread. Since WLM and DB2 think
  that there is still an active user of these WLM resources,
  the following three symptoms may occur:
                                                                .
  1. If you issue an MVS VARY WLM REFRESH command or an MVS
  VARY WLM QUIESCE command against the WLM environment that
  was used by the UDFs, WLM will issue an IWM031I message to
  say that the refresh or quiesce request is in progress.
  However, the request will not complete. It will wait for
  the orphaned resources to be cleaned up.
                                                                .
  WORKAROUND for 1: If this problem occurs, it can be resolved
  by issuing an MVS cancel of the WLM address space. This may
  result in an expected ABEND04E RC00E50013 from DSNX9SPS
  and/or DSNX9WCA.
                                                                .
  2. If you issue a STOP DB2 command, it will issue message
  DSNX922I to notify you that DB2 has begun disconnection of
  the (WLM) stored procedure address spaces but the process
  will not complete. DB2 will not issue message DSNX923I to
  notify you that all (WLM) stored procedure address spaces
  are disconnected. Instead, DB2 will suspend and hang in
  module DSNX9SPS waiting for the orphaned resources to be
  cleaned up.
                                                                .
  WORKAROUND for 2: If this problem occurs, it can be resolved
  either by issuing an MVS cancel of the WLM address space
  or by issuing a STOP DB2 MODE(FORCE) command. This may
  result in an expected ABEND04E RC00E50013 from DSNX9SPS
  and/or DSNX9WCA.
                                                                .
                                                                .
  

Problem conclusion

• DB2 code has changed to add in the missing clean up of UDFs
  that are invoked from inside stored procedure instances.
                                                                .
                                                                .
  ADDITIONAL KEYWORDS:
  SQLSCALARUDF SQLUDF SQLSP SQLSTOREDPROC
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  UK92276 UK92277

Modules/Macros

• DSNXECWA DSNXEUF0
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RA10 PSY UK92276

     UP13/03/22 P F303

• R910 PSY UK92277

     UP13/03/22 P F303

Fix is available

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