LI72660: DB2AGENT SIGSEGV FOLLOWING ERROR WHILE OBTAINING A TABLE QUEUE LATCH

DB2 Version 9.5 Fix Pack 3b for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 1  for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 2a for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 2  for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 4  for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 4a for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 5 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 6a for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 10 for Linux, UNIX, and Windows

APAR status

• Closed as program error.

Error description

• Following a failure to obtain a table queue latch during SMP
  or MPP runtime query processing, the db2 instance can shutdown
  following a sigsegv received a db2agent.
  
  The fix will handle the error more gracefully and avoid to abend
  the instance following a failure to obtain the latch.
  .
  When the db2agent fails to obtain a table queue latch during
  query processing the following messages will be dumped in the
  db2diag.log:
  .
  2007-06-03-04.07.52.012541-300 I84614033E527      LEVEL: Error
  PID     : 2720                 TID  : 183041065728PROC :
  db2agntp (SAMPLE) 42
  INSTANCE: db2inst1             NODE : 042         DB   : SAMPLE
  APPHDL  : 0-65                 APPID: APPID123
  AUTHID  : DB2INST1
  FUNCTION: DB2 UDB, table Q services, sqlktopn, probe:20
  MESSAGE : DIA0001E An internal error occurred. Report the
  following error code:
  "Line=00531, rc1=0x82170001, rc2=0x00000004,
  rc3=0x2e1b20080, msg=TQ already open".
  .
  OR:
  .
  2007-06-03-04.07.52.014940-300 I84618003E504      LEVEL: Error
  PID     : 3695                 TID  : 183041065728PROC :
  db2agntp (SAMPLE) 41
  INSTANCE: db2inst1             NODE : 041       DB:SAMPLE
  APPHDL  : 0-65                 APPID: APPID123
  AUTHID  : DB2INST1
  FUNCTION: DB2 UDB, table Q services, sqlktclo, probe:30
  MESSAGE : DIA0001E An internal error occurred. Report the
  following error code:
  "Line=00389, rc1=0x82170001, rc2=0x00000000,
  rc3=(nil),msg=sqloxltc(tq_latch)".
  .
  Following this initial error while obtaining a table queue
  latch, the db2 processes could abend due to sigsegv due to an
  improper handling of the above error. The following stacks have
  been encountered for the db2 agents that sigsegv:
  .
  - Stack 1 :
   ======================
  
   ossDumpStackTrace + 0x0080
   OSSTrapFile + 0x00aa
   sqlo_trce + 0x033b
   sqloEDUCodeTrapHandler + 0x0074
   determine_cpumask_size + 0x0070
   sqlri_hsjnClose + 0x0c3c
   sqlricjp + 0x0e97
   sqlricls_complex + 0x0ff7
   sqlricls + 0x0068
   sqlra_close_section + 0x0147
   sqlracal_finalcmt_rb + 0x022b
   sqlracal + 0x0311
   sqlrr_cleanup_tran_before_DPS + 0x0469
   sqlrr_tran_router + 0x0734
   sqlrr_subagent_router + 0x0866
   sqleSubRequestRouter + 0x073c
   sqleProcessSubRequest + 0x01aa
   sqleRunAgent + 0x0400
   sqloCreateEDU + 0x0279
   sqloTermEDUServices + 0x057b
   sqloInitEDUServices + 0x0360
   sqloRunInstance + 0x0081
   DBGTerm() + 0x2018
   DB2main + 0x07df
   main + 0x002f
  
  - Stack 2 :
  ======================
  
   ossDumpStackTrace + 0x0080
   OSSTrapFile + 0x00aa
   sqlo_trce + 0x033b
   sqloEDUCodeTrapHandler + 0x0074
   determine_cpumask_size + 0x0070
   sqlri_hsjnItrInit + 0x0000
   sqlrihsjn + 0x055e
   sqlriExecThread + 0x004a
   sqlriSectInvoke + 0x0083
   sqlrr_dss_router + 0x0550
   sqlrr_subagent_router + 0x07eb
   sqleSubRequestRouter + 0x073c
   sqleProcessSubRequest + 0x01aa
   sqleRunAgent + 0x0400
   sqloCreateEDU + 0x0279
   sqloTermEDUServices + 0x057b
   sqloInitEDUServices + 0x0360
   DBGTerm() + 0x2018
   sqloRunInstance + 0x0081
   DB2main + 0x07df
   main + 0x002f
  .
  This APAR addresses the error handling
  following the failure to obtain a table queue latch, so that the
  db2 agent does not sigsegv after the initial error, but return a
  -902 and mark the database as damaged, which would allow to dump
  more diagnostic data collection.
  
  As well, this APAR introduces a new capability to enable
  optionally more diagnostic data collection in case of
  reoccurrence.
  

Local fix

Problem summary

• see problem description
  

Problem conclusion

• First fixed in DB2 UDB Version 9.5, FixPak 1
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  LI72500

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  DB2 UDE ESE LIN

• Fixed component ID

  5765F4104

Applicable component levels

• R910 PSY

     UP

• R950 PSY

     UP