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IT35983: MON_GET_APPL_LOCKWAIT TABLE FUNCTION MIGHT RETURN INCORRECT 'HLD_MEMBER' IN PURESCALE

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APAR status

  • Closed as fixed if next.

Error description

  • In pureScale environment, the MON_GET_APPL_LOCKWAIT table
    function might return incorrect HLD_MEMBER.
    
    This can be shown by the following example.
    
    
    On member 0: insert some rows to table T1, commit
    
    db2 "create table t1(c1 int)"
    db2 "insert into t1 values(1)"
    db2 "insert into t1 values(2)"
    db2 "commit"
    
    
    On member 1: delete some row from T1, without commit
    
    db2 -m +c "delete from t1 where c1=2"
    
    
    On member 2: query on T1 using RR isolation, which is blocked by
    the uncommitted delete on member 1
    
    
    db2 "select * from t1 with rr"
    
    
    The following query using MON_GET_APPL_LOCKWAIT table function
    reports HLD_MEMBER is '0' for the lock wait above. instead of
    '1'.
    
    db2 "SELECT TIMESTAMP(LOCK_WAIT_START_TIME, 0)
    LOCK_WAIT_START_TM , CHAR(LOCK_NAME, 28) NAME ,
    SUBSTR(LOCK_OBJECT_TYPE, 1, 10) OBJECT_TYPE , LOCK_MODE MODE ,
    LOCK_CURRENT_MODE CUR_MODE , LOCK_MODE_REQUESTED MODE_REQ ,
    LOCK_STATUS STATUS , LOCK_ESCALATION ESCAL , INT(LOCK_COUNT)
    COUNT , REQ_MEMBER REQ_MBR , INT(REQ_APPLICATION_HANDLE)
    R_AGENT_ID , HLD_MEMBER HLD_MBR , INT(HLD_APPLICATION_HANDLE)
    H_AGENT_ID , SMALLINT(TBSP_ID) TBSP_ID , SMALLINT(TAB_FILE_ID)
    TAB_ID FROM TABLE(MON_GET_APPL_LOCKWAIT(NULL, -2))"
    
    LOCK_WAIT_START_TM  NAME                         OBJECT_TYPE
    MODE CUR_MODE MODE_REQ STATUS ESCAL COUNT       REQ_MBR
    R_AGENT_ID  HLD_MBR H_AGENT_ID  TBSP_ID TAB_ID
    ------------------- ---------------------------- -----------
    ---- -------- -------- ------ ----- ----------- -------
    ----------- ------- ----------- ------- ------
    2020-03-10-15.35.09 FAFF0080000000000000FFFF54   TABLE       -
    -        S        W      N               0       1      118514
    0           -      -6 -32768
    
      1 record(s) selected.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * AIX/LINUX                                                    *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to db2 v11.1.4.6                                     *
    ****************************************************************
    

Problem conclusion

Temporary fix

Comments

APAR Information

  • APAR number

    IT35983

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B10

  • Status

    CLOSED FIN

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2021-02-21

  • Closed date

    2021-03-13

  • Last modified date

    2021-03-13

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

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

Fix information

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:
14 March 2021