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IT28165: DB2 PURESCALE INSTANCE MAY PANIC DURING BUFFERPOOL DECREASE

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APAR status

  • Closed as program error.

Error description

  • A pureScale instance may panic while a bufferpool decrease
    operation is running. Bufferpool decrease can be initiated from
    STMM or by explicitly resizing a bufferpool to a smaller size.
    This is a very rare timing issue and the likelihood to hit the
    issue is very low. The panic will be reported by an agent
    indicating that a page latch is not held, similar to the
    following db2diag.log message:
    
    FUNCTION: DB2 UDB, SQO Latch Tracing,
    SQLO_SLATCH_CAS64::releaseConflict, probe:330
    MESSAGE :
    ZRC=0x870F011E=-2029059810=SQLO_LATCH_ERROR_EXPECTED_HELD
              "expected latch to be held."
    CALLED  : OS, -, unspecified_system_function
    DATA #1 : String, 39 bytes
    Attempting to unlock an invalid latch:
    DATA #2 : File name, 16 bytes
    sqloLatchCAS64.C
    DATA #3 : Source file line number, 8 bytes
    1054
    DATA #4 : Codepath, 8 bytes
    2
    DATA #5 : String, 125 bytes
    0x0000000000000000: {
       held X: 0
       reserved for X: 0
       shared holders: 0
       firstSharIndex: 0x0
       firstExclIndex: 0x0
    }
    DATA #6 : LatchMode, PD_TYPE_LATCH_MODE, 8 bytes
    0x0 (invalid mode)
    DATA #7 : String, 399 bytes
    {
       state         = 0x0000000000000000
                     = {
                           held X: 0
                           reserved for X: 0
                           shared holders: 0
                           firstSharIndex: 0x0
                           firstExclIndex: 0x0
                       }
       starve X mode = false
       xWaitCount    = 0
       requestCount  = 0
       identity      = SQLB_BPD::bpdLatch_SX (264)
    }
    DATA #8 : Pointer, 8 bytes
    0x0a000302d59785d8
    
    The latch information in the trap file in the FODC directory
    will indicate the agent is holding a page latch in mode: S.
    
    <LatchInformation>
    Holding Latch type: (SQLO_LT_SQLP_SAVEPOINTS__spLatch) -
    Address: (0xa000301836b8680)
    Holding Latch type: (SQLO_LT_SQLP_TENTRY__applLatch) - Address:
    (0xa000301836b8cf0), Line: 873, File: sqlpxreg.C HoldCount: 1
    Holding latch type: (SQLO_LT_SQLB_BPD__bpdLatch_SX) - Address:
    (0xa0003031e7e9968), mode: S, Line: 1650, File: sqlbfix.C
    </LatchInformation>
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to Db2 11.1 Mod 4 Fixpack 5 or higher                *
    ****************************************************************
    

Problem conclusion

  • First fixed in Db2 11.1 Mod 4 Fixpack 5
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT28165

  • 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

    2019-02-19

  • Closed date

    2020-01-16

  • Last modified date

    2020-01-16

  • 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

  • RB10 PSN

       UP

[{"Business Unit":{"code":"BU048","label":"IBM Software"},"Product":{"code":"SSEPGG","label":"DB2 for Linux, UNIX and Windows"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.1","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
16 January 2020