IT34933: REPLICATION OF COMPRESSED PARTITION BLOBS MAY CAUSE ASSERT FAILURE

APAR status

• Closed as program error.

Error description

• When replicating rows containing compressed partition blobs in
  an Enterprise Replication environment an Assert Failure may
  occur indicating memory corruption. An example AF is:
  
  Pool 'CDRGeval1' (0x4665e040)
  Bad free block 0x466aa458
  Assert Failed: Memory free block header corruption detected in
  mt_shm_malloc_segid 3
  IBM Informix Dynamic Server Version 12.10.FC14
  Who: Session(48, informix@server1, 0, 0x44f3ebe8)
  Thread(75, CDRGeval1, 44efd6e8, 1)
  File: mtshpool.c Line: 1834
  Results: Unable to repair pool free list
  Action: Please notify IBM Informix Technical Support.
  stack trace for pid 29128 written to /dumpdir/server1/af.433b9ad
  See Also: /dumpdir/server1/af.433b9ad
  
  The contents of the AF file include:
  Found during mt_shm_malloc_segid 3
  Pool 'CDRGeval1' (0x4665e040)
  Bad free block 0x466aa458
  blk-64
  00000000466aa418: 764f3854 47366179 6a463834 51423673   vO8TG6ay
  jF84QB6s
  00000000466aa428: 78545638 61446d35 4c717848 4a474842   xTV8aDm5
  LqxHJGHB
  00000000466aa438: 61745142 63663142 43202058 73203167   atQBcf1B
  C  Xs 1g
  00000000466aa448: 69467533 75397a6e 54635657 744c4239   iFu3u9zn
  TcVWtLB9
  blk+64
  00000000466aa458: 6d6a4f69 5320697a 6f344452 65723878   mjOiS iz
  o4DRer8x
  00000000466aa468: 6777755a 7377704a 4e484e20 78566972   gwuZswpJ
  NHN xVir
  00000000466aa478: 707a7362 38425174 7162674c 34714644   pzsb8BQt
  qbgL4qFD
  00000000466aa488: 38574945 705a3745 4d764d45 71716472   8WIEpZ7E
  MvMEqqdr
  
  Stack for thread: 75 CDRGeval1
  afstack
  afhandler
  affail_interface
  mt_shm_malloc_segid
  mt_malloc
  old_do_rhpstart
  grouperEvalThread
  cdrTrampolineThread
  th_init_initgls
  startup
  
  
  The corrupted memory block headers may include evidence of the
  uncompressed partition blob data.
  
  Other types of Assert Failure are possible including those that
  cause a fatal exception and crash the server. Example thread
  stacks shown in such AFs include:
  
  Stack for thread: 75 CDRGeval1
  afstack
  mt_ex_throw_sig
  afsig_handler
  <signal frame>
  fmclose
  cdr_db_closetab
  rqmCloseHandleInt
  grouperEvalThread
  cdrTrampolineThread
  th_init_initgls
  startup
  
  Stack for thread: 269 sqlexec
  afstack
  afhandler
  afcrash_interface
  mt_free_mutex
  destroy_session
  sqsetconerr
  _iread
  _igetint
  sqmain
  
  
  On restart of the server it is also possible that further Assert
  Failures may be raised by a CDRGeval thread, for example:
  
  Assert Failed: No Exception Handler
  IBM Informix Dynamic Server Version 12.10.FC14
  Who: Session(34, informix@server1, 0, 0x44f3d748)
  Thread(61, CDRGeval0, 44efe8a8, 1)
  File: mtex.c Line: 508
  Results: Exception Caught. Type: MT_EX_OS, Context: mem
  Action: Please notify IBM Informix Technical Support.
  See Also: /dumpdir/server1/af.425ba6f
  Thread ID 61 will NOT be suspended because
            it is deemed too critical to the server.
  See Also: /dumpdir/server1/af.425ba6f
  
  Stack for thread: 61 CDRGeval0
  afstack
  mt_ex_throw_sig
  afsig_handler
  <signal frame>
  ucvdrop
  ucvreset
  flfree
  opfree
  rsclose
  cdrExpandRow
  grouperCopy
  grouperEvalThread
  cdrTrampolineThread
  th_init_initgls
  startup
  
  Recovery from this situation requires the server to be restarted
  without Enterprise Replication and then the associated replicate
  is made inactive. It may then be dropped and recreated followed
  by a data resync activity to ensure all necessary data has been
  replicated to the target table.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 12.10.xC15 and 14.10.xC6.  *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Informix Server 12.10.xC15 (when available) or    *
  * 14.10.xC6 (when available).                                  *
  ****************************************************************
  

Problem conclusion

• Fixed in Informix Server 12.10.xC15 and 14.10.xC6.
  

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

  INFORMIX SERVER

• Fixed component ID

  5725A3900

Applicable component levels