IBM Support

IT31442: HASH JOIN QUERY CAN HANG IN REBAL

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APAR status

  • Closed as program error.

Error description

  • A query with hash join might hang if REBAL operator is used.
    
    Query plans usually have 2 REBALS top of waiting for bottom one,
    and agents stuck in the bottom one.
    
    The stack trace in hang will have:
    
      0x0900000146DAC860 sqloWaitEDUWaitPost + 0xA00
      0x090000014D4D3804 IPRA.$sqlriREBALWaitForRow
      0x090000014D4CFE18 IPRA.$sqlriREBALcommon
      0x090000014D4D1554 sqlriREBAL1
      0x0900000149EF6298 sqlriSectInvoke
      0x090000014C095A88 sqlrr_smp_router
      0x090000014C091F48 sqlrr_subagent_router
      0x090000014C0740A0 IPRA.$sqleSubRequestRouter
      0x090000014C06E148 sqleProcessSubRequest
      0x0900000146DC5A4C RunEDU
      0x0900000146DA8640 EDUDriver
      0x0900000146C97594 sqloEDUEntry
    
    sqlriREBALWaitForRow is the key function in stack.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to Db2 Version 11.1 Mod 4 Fix Pack 6.                *
    ****************************************************************
    

Problem conclusion

  • First fixed in Db2 Version 11.1 Mod 4 Fix Pack 6.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT31442

  • 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

    2020-01-08

  • Closed date

    2021-03-16

  • Last modified date

    2021-03-16

  • 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:
18 March 2021