IC61638: An FDC is generated which fills up the entire disk.

WebSphere MQ V7.0 Fix Pack 7.0.1.1
WebSphere MQ V7.0 Fix Pack 7.0.1.2

APAR status

• Closed as program error.

Error description

• An FDC is generated as a result of an MQ error. The FDC file
  continually grows and eventually fills up the disk
  space. The connection history section repeatedly loops dumping
  the same connection history data.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Potentially any users of WebSphere MQ experiencing a problem
  that results in an FDC and where the conditions documented in
  the Problem Summary are met.
  
  Platforms affected:
  All Distributed (iSeries, all Unix and Windows)
  ****************************************************************
  PROBLEM SUMMARY:
  A logic error within the connection history dumping code
  caused an infinite loop. The resultant
  FDC would grow to consume all space available until the
  process writing it is killed. The following conditions need to
  be met in order to cause the failure:
  
  1.) An FDC is generated which results in the dumping of the
  connection history information.
  
  2.) There have been sufficient connections such that the
  history array has wrapped.
  
  3.) Wrapping the array alone is not sufficient to induce the
  failure conditions. The additional condition is that, when the
  wrapping occurs, a record boundary for an individual API call
  falls on the array boundary (effectively, the cumulative
  record length of all the whole records in the array needs to
  divide cleanly by the array length such that a new record
  entry begins at the start of the wrapped array).
  
  4.) When the FDC is produced, the current index into the
  history log also needs to be at the start (in other words, the
  array has only just wrapped).
  

Problem conclusion

• WebSphere MQ was modified to ensure that the FDC generation
  code does not continually loop round dumping the connection
  history table. Note that this fix does not address the root
  cause of why the FDC was generated in the first place.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
                     v7.0
  Platform           Fix Pack 7.0.1.0
  --------           --------------------
  Windows            U200306
  AIX                U823774
  HP-UX (PA-RISC)    U823665
  HP-UX (Itanium)    U823667
  Solaris (SPARC)    U823772
  Solaris (x86-64)   U824344
  iSeries            tbc_p700_0_1_0
  Linux (x86)        U823664
  Linux (x86-64)     U823773
  Linux (zSeries)    U823668
  Linux (Power)      U823666
  
  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 WINDOWS V7

• Fixed component ID

  5724H7220

Applicable component levels

• R700 PSY

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