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LI72985: SIGSEGV IN SQLNO_SMP_CREATE_PART_FROM_KEY_ORDER

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • A query when compiled in SMP mode (INTRA_PARALLEL enabled,
    DEGREE >1) crashes in the Optimizer with the following stack:
    sqlno_smp_create_part_from_key_order
    sqlnoSmpPlanMateOp
    sqlnoSmpPlanPipeOp
    sqlno_smp_process_subsection
    sqlnoSmpPlanPass
    sqlnoSmpPostPassMain
    sqlno_final_phase
    .
    The types of queries that are vulnerable are queries that use
    scalar aggregation (i.e. COUNT, DISTINCT, MIN, MAX) and use the
    PARTITION BY clauses. However, not all queries using these
    combinations are vulnerable to the problem.
    

Local fix

  • The problem occurs in SMP mode. So disabling SMP parallelism
    (via DFT_DEGREE 1 in the db cfg, SET CURRENT DEGREE 1 prior
    to running the SQL or setting INTRA_PARALLEL NO) are valid
    workarounds.
    

Problem summary

  • USERS AFFECTED: ALL
    PROBLEM DESCRIPTION:
    A query when compiled in SMP mode (INTRA_PARALLEL enabled,
    DEGREE >1) crashes in the Optimizer.
    
    PROBLEM SUMMARY:
    The stack trace is as follows:
    
    sqlno_smp_create_part_from_key_order
    sqlnoSmpPlanMateOp
    sqlnoSmpPlanPipeOp
    sqlno_smp_process_subsection
    sqlnoSmpPlanPass
    sqlnoSmpPostPassMain
    sqlno_final_phase
    .
    The types of queries that are vulnerable are queries that use
    scalar aggregation (i.e. COUNT, DISTINCT, MIN, MAX) and use the
    PARTITION BY clauses. However, not all queries using these
    combinations are vulnerable to the problem.
    

Problem conclusion

  • First fixed in Version 9.5, FixPak 1
    

Temporary fix

  • The problem occurs in SMP mode. So disabling SMP parallelism
    (via DFT_DEGREE 1 in the db cfg, SET CURRENT DEGREE 1 prior
    to running the SQL or setting INTRA_PARALLEL NO) are valid
    workarounds.
    

Comments

APAR Information

  • APAR number

    LI72985

  • Reported component name

    DB2 UDE ESE LIN

  • Reported component ID

    5765F4104

  • Reported release

    950

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2008-01-03

  • Closed date

    2009-10-01

  • Last modified date

    2009-10-01

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

    LI72139

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

Modules/Macros

  • ENG_SQNO
    

Fix information

  • Fixed component name

    DB2 UDE ESE LIN

  • Fixed component ID

    5765F4104

Applicable component levels

  • R810 PSN

       UP

  • R820 PSN

       UP

  • R910 PSN

       UP

  • R950 PSN

       UP

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Document Information

Modified date:
01 October 2009