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

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You can track all active APARs for this component.

 

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 number

    IT21912

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2017-08-09

  • Closed date

    2018-03-16

  • Last modified date

    2018-03-16

  • 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

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.1","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
16 March 2018