IT21912: A REPEATED POSITIONED UPDATE ON A ROW CAN LEAD TO AN ABEND/CRASHon sqlristm

Db2 Version 11.1 Mod 3 Fix Pack 3 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod3 Fix Pack3 iFix001 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod3 Fix Pack3 iFix002 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 5 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 7 for Linux, UNIX, and Windows

APAR status

• Closed as program error.

Error description

• A positioned update is an update on a row using the WHERE
  CURRRENT OF clause.
  This will reference an open cursor that was positioned on a row
  earlier on.
  If the same, or a different update is executed on the same row
  without moving the cursor position,
  then this second update statement can lead to a DB2 abend
  because of a stale pointer.
  This would be caused by agent workspace cache management
  removing the executable section of the cursor
  from the local edu workspace cache in between executions.
  
  Example of DB2 stack :
  
  CALLSTCK:
    [0] 0x000003FFF9BEB496 sqloPGRPRegisterOneCrash + 0x192
    [1] 0x000003FFF9CBE23A sqloEDUCodeTrapHandler + 0x472
    [2] 0x000003FF01009DF0 0x000003FF01009DF0 + 0x0
    [3] 0x000003FFF9C7A09C sqlofmblkEx + 0x5C
    [4] 0x000003FFFA827A06 _Z8sqlristmP8sqlrr_cbP9sqlri_shdi +
  0x72
    [5] 0x000003FFFA430334
  _Z32sqlra_sqlW_mem_free_sibling_listP8sqlrr_cbP23sqlra_workspace
  _siblingPm + 0x4B0
    [6] 0x000003FFFA4381D0
  _Z24sqlra_sqlW_mem_freespaceP8sqlrr_cbmPmi + 0x9A8
    [7] 0x000003FFFA424D9A
  _Z28sqlra_sqlW_check_for_cleanupP8sqlrr_cbmP7OSSTick + 0x5BA
    [8] 0x000003FFFA42E606
  _Z34sqlra_sqlW_get_dynamic_section_newP8sqlrr_cbP16sqlra_cached_
  var + 0x17AA
    [9] 0x000003FFFA3B106C
  _Z14sqlra_load_varP8sqlrr_cbP16sqlra_cached_var + 0x94
    [10] 0x000003FFFA44AFB2 _Z13sqlra_get_varP8sqlrr_cbiibPbS1_ +
  0x3B4A
    [11] 0x000003FFFA185CEA
  _Z13sqlrr_prepareP14db2UCinterfaceP16db2UCprepareInfo + 0x416
    [12] 0x000003FFF853A1A8
  _Z19sqljs_ddm_prpsqlsttP14db2UCinterfaceP13sqljDDMObject + 0x378
    [13] 0x000003FFF852A536
  _Z21sqljsParseRdbAccessedP13sqljsDrdaAsCbP13sqljDDMObjectP14db2U
  Cinterface + 0x3C6
    [14] 0x000003FFF852A9F2
  _Z10sqljsParseP13sqljsDrdaAsCbP14db2UCinterfaceP8sqeAgentb +
  0x322
    [15] 0x000003FFF851E2EA
  /home/db2inst1/sqllib/lib64/libdb2e.so.1 + 0x1EA72EA
    [16] 0x000003FFF8522A7E
  /home/db2inst1/sqllib/lib64/libdb2e.so.1 + 0x1EABA7E
    [17] 0x000003FFF85231EE
  _Z17sqljsDrdaAsDriverP18SQLCC_INITSTRUCT_T + 0x14E
    [18] 0x000003FFF8177EDC _ZN8sqeAgent6RunEDUEv + 0x548
    [19] 0x000003FFFB3D35F6 _ZN9sqzEDUObj9EDUDriverEv + 0x222
    [20] 0x000003FFF9CBFDBE sqloEDUEntry + 0x2BE
    [21] 0x0000004C374B92C6 /lib64/libpthread.so.0 + 0x92C6
    [22] 0x0000004C37353432 /lib64/libc.so.6 + 0x10D432
  

Local fix

• Increase the workspace cache , e.g. db2set
  DB2_SQLWORKSPACE_CACHE=200
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * ALL                                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to DB2 Version 11.1 Mod 3 and Fix Pack 3             *
  ****************************************************************
  

Problem conclusion

• Problem was first fixed in DB2 Version 11.1 Mod 3 and Fix Pack 3
  

Temporary fix

Comments

APAR Information

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

  IT20547

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

Fix information

• Fixed component name

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• RB10 PSN

     UP