PI83023: RELOAD SUBTASK HUNG AT DSNURWBR WAITING FOR THE RESUME FROM SORTSUBTASK 17/06/16 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• There is an obscure timing window where a variable that is
  involved in the synchronization between the reload task and
  the sort task could get re-initialized when it should not be.
  This could cause the reload task (DSNURWBR) to issue a resume
  to the sort task, with the sort task then issuing a suspend
  and not detecting that it had already been resumed,
  causing the sort task to suspend when it should not.
  The reload task could then easily suspend on an different pipe,
  causing a hang.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All DB2 11 for z/OS with PI73882/UI44914                     *
  * applied and DB2 12 for z/OS users of the                     *
  * LOAD or REORG utilities with a zIIP                          *
  * configured.                                                  *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * REORG or LOAD hang when run on a                             *
  * partitioned table space with multiple                        *
  * indexes and a System z Integrated                            *
  * Information Processor (zIIP)                                 *
  * configured.                                                  *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply corrective PTF when available.                         *
  ****************************************************************
  User ran a REORG of a partitioned table space with multiple
  indexes and a System z Integrated Information Processor (zIIP)
  configured.  The job hung and had to be cancelled.
  
  A timing window exists when multiple RELOAD tasks in LOAD or
  REORG, running on different partitions and attempting to pass
  index keys to multiple sort tasks, with a zIIP configured, can
  issue a RESUME to a sort task before the sort task initializes
  a flag that controls whether the sort task issues a SUSPEND
  or continues processing.  If the timing is right, this can
  cause both the sort and reload tasks to be suspended,
  waiting on each other, causing the hang.
  

Problem conclusion

• The sort task initialization of the suspend/resume flags has
  been corrected.
  

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:

  UI49143 UI49144

Modules/Macros

• DSNUGSRP DSNURPDS
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RC10 PSY UI49143

     UP17/08/12 P F708 {

• RB10 PSY UI49144

     UP17/08/12 P F708 {

Fix is available

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