PH45504: -DIS THD(*) DOES NOT ALWAYS ALLOW TO DETERMINE THE CURRENT STATE OF A DDF THREAD

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The -DISPLAY THREAD(*) command does not allow to accurately
  determine the current state of a DDF thread that is using
  KEEPDYNAMIC(YES) or High Performance DBAT (HPDBAT).
  When a KEEPDYNAMIC(YES) or HPDBAT thread reaches a commit point,
  the DBAT and connection are kept together (the DBAT is not
  pooled).
  Using the -DIS THD(*) command output for these threads, you
  cannot distinguish between the case where such a thread is
  processing SQL requests as part of an active transaction, or
  whether such a thread has reached a transaction boundary and is
  just waiting for a new request to come in that will start a new
  transaction.
  As IFCID 0148 READS requests use the same thread status
  information as -DIS THD, this also applies to IFCID0148
  requests.
  
  
  Additional symptoms or keywords:
  ********************************
  Db2DDF DDF HIPERF HPDBAT
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Db2 for z/OS Distributed Data Facility                   *
  * (DDF) Users.                                                 *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Inability to determine the status                            *
  * of an active distributed server                              *
  * thread (DBAT) in a wait state.                               *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply corrective PTF when available                          *
  ****************************************************************
  When a Db2 -DISPLAY THREAD command or an external monitoring
  tool using IFCID148 is used to determine the active threads
  running in a Db2 subsystem, any active DBAT is always shown
  with a status of RA. Since some active DBATs are
  well-behaved while some are not, one is unable to correctly
  identify the actual status of a DBAT. If the purpose of
  utilizing the -DISPLAY THREAD command or IFCID148 data was
  to locate a misbehaving DBAT with the aim of cancelling the
  DBAT, the inability to determine a DBAT's actual status may
  result in a DBAT being incorrectly terminated.
  Also, when a dump of a Db2 subsystem is presented to IBM
  for problem analysis, the true status of a DBAT in the dump
  is cumbersome to determine.
  

Problem conclusion

• Db2 has been changed to provide additional thread status
  values for distributed server threads (DBATs) in the output
  of a -DISPLAY THREAD command or IFCID148 data obtained via
  an IFC READS call. The new values will be displayed or
  returned, depending on the actual status of a DBAT, instead
  of a status value of RA, which would have been previously
  displayed or returned prior to the installation and
  activation of this APAR.
  The new status values are:
  RP - denotes an active, high performwance DBAT waiting for
       the next transaction from its remote connection and the
       DBAT is not a candidate for idle thread detection and
       termination based on IDTHTOIN subsystem parameter
  RD - denotes an active, KeepDynamic-refreshable DBAT
       waiting for the next transaction from its remote
       connection and the DBAT is not a candidate for idle
       thread detection and termination based on IDTHTOIN
       subsystem parameter
  RH - denotes an active DBAT waiting for the next transaction
       from its remote connection but it is being kept active
       with its connection due to resources being held past a
       commit/rollback. A DBAT with this status is a candidate
       for idle thread detection and termination based on
       IDTHTOIN subsystem parameter. The possible
       resources are:
       - open, WITH HOLD cursor(s)
       - allocated declared global temporary table(s)
       - held lob locators
       - commit performed within a stored procedure which
         requires a two-phase commit/rollback from the
         client connection
       - active KEEPDYNAMIC package(s) but the client did
         not request KeepDynamic refresh
  Note: a client connection must inform Db2 that it is
  performing sysplex workload balancing or client affinities
  when using KEEPDYNAMIC packages to enable
  KeepDynamic refresh.
  The new distributed thread status values have also been
  added to the Db2 Dump Formatter, option DS=x, for the
  threads that originate and are running in the ssidDIST
  address space.
  Refer to this APAR's ++HOLD DOC for more details on the new
  thread status values.
  The online product documentation will be updated for both
  Db2 12 and Db2 13:
  https://www.ibm.com/docs/en/db2-for-zos/12 and
  https://www.ibm.com/docs/en/db2-for-zos/13.
  

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:

  UI81313 UI81314

Modules/Macros

• DSNWDFDS DSNVDTA  DSNWAACT
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RC10 PSY UI81313

     UP22/07/13 P F207

• RD10 PSY UI81314

     UP22/07/13 P F207

Fix is available

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