IBM Support

IT19780: IN RARE TIMING CONDITION, THE DATABASE CAN HANG DUE TO DEADLATCHBETWEEN HADR PROCESSES.

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • In a DB2 v11.1.0.0 or v11.1.1.1 database instance with HADR
    enabled and multiple Standbys, in a rare timing condition a
    deadlatch can occur between db2hadrp EDUs utliizing the
    hdrDbLatch and hdrSharedLatch latches.
    
    Stack dumps will show function sequence similar to this:
    
    __db2hadrp.0.1__
    0x000000000043C94D
    _ZN10sqlo_latch3getEmPKcmP16SQLO_LATCH_TABLEb14SQLO_LT_VALUES +
    0x0205<
    0x0000000000436258
    _Z16sqloltch_notrackP10sqlo_latchmPKcmP16SQLO_LATCH_TABLEb14SQLO
    _LT_VALUES + 0x0074<
    0x00007F3CB32F5EFE address: 0x00007F3CB32F5EFE ; dladdress:
    0x00007F3CB0821000 ; offset in lib: 0x0000000002AD4EFE ;<
    0x00007F3CB330A653
    _Z34hdrUpdateSslLabelSemiDynamicConfigP8HDR_DBCBP5sqlcaPc +
    0x02ac<
    0x00007F3CB32EE54C
    _ZN11HADR_SHARED36hshRefreshConfigAndDetermineProtocolEP8HDR_DBC
    BP13HDR_SOCKET_CB18HDR_SOCKET_SESSION + 0x0252<
    0x00007F3CB32ECB83
    _ZN11HADR_SHARED12hshAddSocketEP8HDR_DBCBi18HDR_SOCKET_SESSION +
    0x0497<
    0x00007F3CB3306316
    _Z19hdrHandleRemoteConnP8HDR_DBCBP14sqlpMasterDbcb + 0x0873<
    
    Waiting on latch type: (SQLO_LT_sqeLocalDatabase__hdrDbLatch) -
    Address: (0x20d9d0310), Line: 4612, File: hdrCom.C
    Holding Latch type: (SQLO_LT_HADR_SHARED__hshSharedLatch) -
    Address: (0x7f3bfe93e318), Line: 1013, File:
    /view/db2_v111m1fp1_linuxamd64_g000030/vbs/engn/include/hdrShare
    d.h HoldCount: 1
    
    
    __db2hadrp.2.1__
    0x00007F3CB325F547 _ZN11HADR_SHARED14hshLatchSharedEv + 0x0077<
    0x00007F3CB32ECE7B _ZN11HADR_SHARED14hshGetSocketCbEiPK8HDR_DBCB
    + 0x0103<
    0x00007F3CB32F9B21 _Z13hdrSendBufferiPcmPmP8HDR_DBCB + 0x04db<
    0x00007F3CB32FD20B
    _Z10hdrSendMsgP8HDR_DBCBiP13HDR_RQST_COMMbP14SqlzDB2Version +
    0x15e9<
    0x00007F3CB32FB81E
    _Z17hdrWrapAndSendMsgP8HDR_DBCB9HDR_RTYPEjPcljPP13HDR_RQST_COMM
    + 0x0688<
    0x00007F3CB331573F _Z16hdrSendHeartBeatP8HDR_DBCBm + 0x1178<
    0x00007F3CB328E808
    _Z37hdrPrepareToEnterOfflinePeerOnPrimaryP8HDR_DBCBP14SQLP_LOCK_
    INFO + 0x0ef5<
    0x00007F3CB32B7BDF _ZN6hdrEdu7hdrEduPEbPm + 0xa80f<
    
    Waiting on latch type: (SQLO_LT_HADR_SHARED__hshSharedLatch) -
    Address: (0x7f3bfe93e318), Line: 1013, File:
    /view/db2_v111m1fp1_linuxamd64_g000030/vbs/engn/include/hdrShare
    d.h
    Holding Latch type: (SQLO_LT_sqeLocalDatabase__hdrDbLatch) -
    Address: (0x20d9d0310), Line: 9950, File: hdrEdu.C HoldCount: 1
    Holding Latch type: (SQLO_LT_HDR_DBCB__hdrOfflinePeerLatch) -
    Address: (0x7f3c02d1f428), Line: 9963, File: hdrEdu.C HoldCount:
    1
    Holding Latch type: (SQLO_LT_SQLP_DBCB__sqlpLogStreamLockLatch)
    - Address: (0x7f3c0d800b18), Line: 9966, File: hdrEdu.C
    HoldCount: 1
    

Local fix

  • Fixed in fixpack inclusive of this APAR fix.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 11.1 Mod1 Fix Pack 1 iFix001                  *
    ****************************************************************
    

Problem conclusion

  • First fixed in DB2 11.1 Mod1 Fix Pack 1 iFix001
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT19780

  • 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

    2017-03-20

  • Closed date

    2017-05-01

  • Last modified date

    2017-05-01

  • 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

[{"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","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
29 June 2020