IBM Support

IT31335: IF COLUMNAR FUNCTIONALITY IS USED ON A SYSTEM WITH INTEL CPU THAT SUPPORTS AVX-512 MIGHT TRAP IN VECTORSIMD::COMPACTVECTORCPU

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APAR status

  • Closed as program error.

Error description

  • Queries using column based engine (BLU) may cause DB2 instance
    to crash with signal #11 (Unix/Linux) or Exception C0000005
    (Windows). The trap file might look like this:
    
    <??$compactVectorCPU@$05_J@VectorSIMD@types@ibm_cde@@SA_KPEIA_J_
    KPEIB_JPEIB_K1@Z> <NotFound:-1>
    
    <??$compactAndAppendInlined@V?$Integer@_J@types@ibm_cde@@@?$Vect
    or@VDecimal@types@ibm_cde@@$0A@$0A@@types@ibm_cde@@QEBAXPEBVBitS
    tring@12@QEAUSQLO_MEM_POOL@@PEAV?$VectorBase@$0A@$0A@@12@@Z>
    
    <?compactAndAppendGeneral@?$VectorBase@$0A@$0A@@types@ibm_cde@@Q
    EBAXPEBVBitString@23@PEAV123@QEAUSQLO_MEM_POOL@@@Z>
    <NotFound:-1>
    
    <??$processInputsSynchronously_helper@V?$Integer@_J@types@ibm_cd
    e@@$00@LookupGroupingHashTableEvaluator@query@ibm_cde@@AEAAXXZ>
    <NotFound:-1>
    
    <??$processInputsSynchronously_helper1@V?$Integer@_J@types@ibm_c
    de@@@LookupGroupingHashTableEvaluator@query@ibm_cde@@AEAAXXZ>
    <NotFound:-1>
    
    <?processInputsSynchronously@LookupGroupingHashTableEvaluator@qu
    ery@ibm_cde@@MEAAXXZ> <NotFound:-1>
    
    <?evaluate@Evaluator@query@ibm_cde@@UEAAX_N0AEAW4EvaluatorRestar
    tState@123@PEAVOptPredicateTracker@23@@Z> <NotFound:-1>
    
    <?evaluate@EvaluationRoutine@query@ibm_cde@@QEAAPEAVQueue@23@IPE
    AUsql_static_data@@@Z> <NotFound:-1>
    
    <?evaluateChain@Scheduler@query@ibm_cde@@AEAAXPEAVEvaluationRout
    ine@23@AEA_K@Z> <NotFound:-1>
    
    <?runWorkerThread@Scheduler@query@ibm_cde@@CAPEAXPEAXPEAH@Z><Not
    Found:-1>
    
    <?cdeEntryPointImpl@query@ibm_cde@@YAHPEAVsqeAgent@@PEAX1@Z><Not
    Found:-1>
    
    <?startCdeSubagent@cdeInterface@@SAHPEAVsqeAgent@@@Z><NotFound:-
    1>
    (snip)
    
    Another variation of the stack
    
    <ibm_cde::types::VectorSIMD::compactVectorCPU>
    <compactAndAppendInlined>
    <ibm_cde::types::VectorBase<ibm_cde::types::NullIndIncluded,
    ibm_cde::types::PolicySIMPLE>::compactAndAppendGeneral>
    <ibm_cde::query::LookupGroupingHashTableEvaluator::processInputs
    Synchronously_helper>
    <processInputsSynchronously_helper1>
    <ibm_cde::query::LookupGroupingHashTableEvaluator::processInputs
    Synchronously>
    <ibm_cde::query::Evaluator::evaluate>
    <ibm_cde::query::EvaluationRoutine::evaluate>
    

Local fix

  • db2set DB2_CPU_FEATURE_DISABLE=AVX512
    Instance restart is needed.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * BLU (column based query) users on AVX-512 capable Intel CPU. *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Apply v11.1 Fixpack 6 to DB2 server                          *
    ****************************************************************
    

Problem conclusion

  • First fixed in v11.1 Mod 4 Fixpack 6.
    

Temporary fix

  • See LOCAL FIX
    

Comments

APAR Information

  • APAR number

    IT31335

  • 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

    2019-12-18

  • Closed date

    2021-03-29

  • Last modified date

    2021-03-29

  • 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

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

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

Document Information

Modified date:
31 March 2021