IZ01794: WEBSPHERE MQ QUEUE MANAGER FAILS TO START WHEN TRANSACTION'S FIRST LSN IS NOT IN ACTIVE LOG AFTER DISK SPACE ISSUE.

WebSphere MQ V6.0 for iSeries Fix Pack 6.0.2.3
WebSphere MQ V6.0 Fix Pack 6.0.2.3
WebSphere MQ 6.0 for HP OpenVMS Alpha and Itanium - Fix Pack 6.0.2.7
WebSphere MQ 6.0 for HP OpenVMS Alpha and Itanium - Fix Pack 6.0.2.10 (FP03)

APAR status

• Closed as program error.

Error description

• If a transaction fails immediately after reserving a restart
  point in the recovery log then it is possible that the only
  reference to the transaction is in a checkpoint. If the queue
  manager fails with a transaction in this state then it is
  possible that the subsequent restart will fail.
  This is a very small timing window and is very unlikely to
  match subsequent restart problems. Analysing a problem at this
  level is very complex and if a reasonable suspicion of a match
  occurs then L3 should be involved.
  The sequence of probes
  HL008001, AL020000, AT013009, KN002003
  at queue manager restart would indicate a potential duplicate
  of this problem (which should then be verified by L3).
  If the queue manager logs are dumped then the oldest transaction
  will be seen to have a non-null FirstLSN (matching the LSN in
  the HL008001 FDC), but a null LastLSN.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  The most likely cause of this problem is that a shortage of
  disk space causes an in-tran MQPUT to fail. IY79906 should also
  be considered in these circumstances, as that resolves a
  checkpoint issue related to disk space issues.
  
  Platforms affected:
   All Distributed (iSeries, all Unix and Windows)
  ****************************************************************
  PROBLEM SUMMARY:
  It is possible for a transaction to be referenced in a
  checkpoint, even though that transaction has never written a
  log record. If the transaction then ends without ever writing a
  log record it is important that the end of the transaction is
  recorded in the log, in case restart recovers the original
  reference and then does not realize the transaction ended.
  The check as to whether to write the end of the transaction log
  record was based only upon whether the transaction had written
  a log record and did not take into account that the transaction
  might have been referenced in a checkpoint without ever
  actually writing a log record (a very rare occurrence).
  

Problem conclusion

• The decision as to whether the end transaction is recorded in
  the log is now based upon whether the transaction wrote a log
  record, or was referenced in a checkpoint. The number of
  instances where one occurs without the other is so small as to
  be of no consideration from a performance standpoint.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
                     v6.0
  Platform           Fix Pack 6.0.2.3
  --------           --------------------
  Windows            U200279
  AIX                U811346
  HP-UX (PA-RISC)    U811630
  HP-UX (Itanium)    U811631
  Solaris (SPARC)    U811632
  Solaris (x86-64)   U811633
  iSeries            SI27288
  Linux (x86)        U811634
  Linux (x86-64)     U811635
  Linux (zSeries)    U811636
  Linux (Power)      U811637
  Linux (s390x)      U811638
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available, information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

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:

Fix information

• Fixed component name

  WMQ LIN X86 V6

• Fixed component ID

  5724H7204

Applicable component levels

• R600 PSY

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