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IT39085: HIGH "SQLO_LT_SQLB_BP_AREA_INFO_PAGEAREA__CLOCKLATCH" CONTENTIONS ON DB2 PURESCALE

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APAR status

  • Closed as program error.

Error description

  • On Db2 pureScale environment, when freeing up one of existing
    pages in the bufferpool to accomodate a new page in, Db2 might
    excessively victimizes pages using the clock pointer algorithm
    and incurs "SQLO_LT_SQLB_BP_AREA_INFO_PAGEAREA__CLOCKLATCH"
    contentions against other EDUs.
    
    Following stack trace is an example of
    SQLO_LT_SQLB_BP_AREA_INFO_PAGEAREA__CLOCKLATCH conflict where a
    page is beings victimized via Page Clock algorithm:
    
      0x0900000031A5DC98 sqloXlatchConflict + 0x8F8
      0x0900000033212D90
    sqlbGetVictimFromPageClockPtr__FP12SQLB_GLOBALSP15SQLB_BufferPoo
    lP19SQLB_PAGE_VICTIM_CBP11SQLB_FIX_CB + 0xC10
      0x0900000033213800
    sqlbFreeUpSlot__FP11SQLB_FIX_CBPUiPP8SQLB_BPDCP13SQLB_PAGE_KEYUl
    + 0x920
      0x09000000333BBF9C
    sqlbGetVictimSlot__FP11SQLB_FIX_CBiPUiPP8SQLB_BPDUlCP13SQLB_PAGE
    _KEY + 0xBC
      0x09000000333AD5C0 sqlbGetPageFromDisk__FP11SQLB_FIX_CBi +
    0xE0
      0x0900000032E77438 sqlbfix__FP11SQLB_FIX_CB + 0x19B8
      0x0900000032CE4198 sqldFetchDirect__FP13SQLD_DFM_WORK + 0x4B98
      0x0900000032CADAF4
    sqldDataFetch__FP8SQLD_CCBP8SQLZ_RIDUlP7SQLI_CB + 0x2FB4
      0x09000000347474B4
    IPRA.$sqliScanLeaf2__FP7SQLI_CBP11SQLI_SFGLOB + 0x974
      0x0900000034746614 sqlifnxt__FP7SQLI_CBP11SQLI_SFGLOB + 0xC54
      0x09000000328AEB04
    sqlirdk__FP8sqeAgentP10SQLI_IXPCRP9SQLD_IXCBUlP8SQLD_KEYP12SQLI_
    KEYDATAP9sqli_scanPi + 0x2224
      0x0900000032CB01B8 sqldIndexFetch__FP8SQLD_CCBP8SQLZ_RID +
    0x978
      0x0900000032CB33BC
    sqldRowFetch__FP8sqeAgentP8SQLD_CCBUlT3PP10SQLD_VALUEP8SQLZ_RIDT
    3P12SQLD_ID_LISTP9SQLP_LSN8 + 0x97C
      0x0900000034369EBC sqlriFetch__FP8sqlrr_cbP9sqlri_taol + 0x29C
      0x090000003885FEA8 sqlriNljnNonPiped__FP8sqlrr_cb + 0x6A8
      0x09000000388C9EA8 sqlriZZOpenDims__FP8sqlrr_cbP10sqlri_zzob +
    0x528
      0x09000000388CA264 sqlriZZInit__FP8sqlrr_cbP10sqlri_zzob +
    0x64
      0x09000000388CC5FC sqlriZigZagJoin__FP8sqlrr_cb + 0x89C
      0x0900000038765CA8 sqlriunn__FP8sqlrr_cbP10sqlri_stob + 0x468
      0x0900000038765184 sqlriset__FP8sqlrr_cb + 0x84
      0x090000003479CCA8 sqlriSectInvoke__FP8sqlrr_cbP12sqlri_opparm
    + 0x688
      0x0900000033C02E94
    sqlrr_process_fetch_request__FP14db2UCinterface + 0xD14
      0x0900000033BFE9EC
    sqlrr_fetch__FP14db2UCinterfaceP15db2UCCursorInfo + 0x1FCC
      0x0900000038F92540
    sqljs_ddm_cntqry__FP14db2UCinterfaceP13sqljDDMObject + 0x4C0
      0x0900000038F25700
    sqljsParseRdbAccessed__FP13sqljsDrdaAsCbP13sqljDDMObjectP14db2UC
    interface + 0x220
      0x0900000038F28834
    sqljsParse__FP13sqljsDrdaAsCbP14db2UCinterfaceP8sqeAgentb +
    0x22B4
      0x0900000032694FFC
    IPRA.$sqljsSqlam__FP14db2UCinterfaceP8sqeAgentb + 0xEFC
      0x090000003269D7B4
    sqljsDriveRequests__FP8sqeAgentP14db2UCconHandle + 0xB4
      0x0900000032692F1C
    IPRA.$sqljsDrdaAsInnerDriver__FP18SQLCC_INITSTRUCT_Tb + 0x141C
      0x090000003269033C sqljsDrdaAsDriver__FP18SQLCC_INITSTRUCT_T +
    0x33C
      0x0900000031B20920 RunEDU__8sqeAgentFv + 0xB60
      0x0900000031AFA840 EDUDriver__9sqzEDUObjFv + 0x300
      0x09000000319D9500 sqloEDUEntry + 0x360
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to 11.1.4.7                                          *
    ****************************************************************
    

Problem conclusion

  • Upgrade to 11.1.4.7
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT39085

  • 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

    2021-11-15

  • Closed date

    2022-04-16

  • Last modified date

    2022-04-16

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

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

    IT41023 IT41024

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSEPGG","label":"DB2 for Linux- UNIX and Windows"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.1","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
14 July 2022