IBM Support

IT35231: ONE COMPLEX QUERY TAKES VERY LONG TIME TO FINISH AFTER MIGRATINGFROM V10.5

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APAR status

  • Closed as program error.

Error description

  • Customer reported a severe performance issue for one query in
    their workload after migrating from v10.5 to v11.1.
    
    Investigation found that query with very wide grouping key (in
    this case it's 29-words long)
    may expose one hash function implementation limitation which
    causes bad collision and lead
    to poor query performance.
    

Local fix

  • N/A
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * all users                                                    *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * upgrade to Db2 111m4fp6 or higher                            *
    ****************************************************************
    

Problem conclusion

  • upgrade to 111m4fp6 or higher
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT35231

  • 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

    2020-12-10

  • Closed date

    2021-03-12

  • Last modified date

    2021-03-12

  • 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:
13 March 2021