IT42690: MQ queue manager might report AMQ6762E(log extent corrupt) during startup

APAR status

• Closed as program error.

Error description

• Upon queue manager startup the queue manager might report one or
  more recovery log extent(s) as
  corrupt in the queue manager error logs.
  
  Error message:
  
  11/27/2022 04:30:34 PM - Process(1805476.5) User(mqm)
  Program(amqzmuc0)
                      Host(ibmhost1) Installation(Installation1)
                      VRMF(9.3.0.0) QMgr(TESTQMGR)
                      Time(2022-11-27T15:30:34.437Z)
                      CommentInsert1(S0000181.LOG)
  
  AMQ6762E: IBM MQ log extent S0000181.LOG corrupt.
  
  EXPLANATION:
  Log extent S0000181.LOG has been detected as corrupt and is not
  valid for use.
  ACTION:
  Determine how the log extent has become corrupt and take action
  to ensure that
  this extent is no longer required for either restart or media
  recovery. This
  might require taking media images.
  
  AMQ6762E: IBM MQ log extent S000nnnn.LOG corrupt.
  
  This problem is unlikely to cause any issue in the queue manager
  other than generating the error
  message.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users using queue manager with LINEAR logging and
  LogManagement=Automatic
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  This problem occurred due to timing condition causing an MQ
  thread trying to access a log extent before the completion of
  the initialization of that log extent by another thread.
  

Problem conclusion

• MQ code has been modified to prevent the thread accessing the
  log extent before the completion of initialization to resolve
  the issue.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.3 LTS   9.3.0.5
  v9.x CD    9.3.3
  
  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

  MQ BASE V9.3

• Fixed component ID

  5724H7291

Applicable component levels