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IT19023: AFTER CRASH RECOVERY, AN DEFERRED ONLINE REORG CLEANUP MIGHT CAUSE AN X ROW LOCK MISSING FOR AN INDOUBT TRANSACTION.

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APAR status

  • Closed as program error.

Error description

  • If there was a database outage due to hardware or software
    failure, and at the time of the outage there was an online reorg
    (OLR) running and there was an indoubt transaction modifying the
    same table that is being reorganized, there is a chance that the
    inodubt transaction modified a row that is also being considered
    by OLR.  After crash recovery, the database is open for new
    connections.  Locks should be reacquired data changed by the
    indoubt transaction.  There is a chance that one of the row
    modified by the indoubt transaction is not reacquired.  Instead,
    the unfinished OLR acquired an NS lock on that row.  Queries
    from new connections might be able to see this row, before the
    indoubt transaction is resolved.
    
    One can find the existence of deferred OLR after crash recovery
    by the following message in db2diag.log:
    
    2017-01-29-20.50.46.579355-300 I16657073E525         LEVEL: Info
    PID     : 4278                 TID : 140077770467072 KTID : 4879
    PROC    : db2sysc
    INSTANCE: rzheng               NODE : 000            DB   :
    REORGDB
    APPHDL  : 0-21                 APPID: *LOCAL.DB2.170130015058
    HOSTNAME: hotellnx118
    EDUID   : 83                   EDUNAME: db2reorg (REORGDB)
    FUNCTION: DB2 UDB, data management,
    sqldOLRCleanupAfterCrashRecovery, probe:5701
    DATA #1 : <preformatted>
    Starting ONLINE REORG cleanup (2;3), TID=0000000000000E84.
    
    One can find the existence of indoubt transaction via the
    following :
    
    2017-01-29-20.50.45.359106-300 I16653970E594         LEVEL: Info
    PID     : 4278                 TID : 140081482426112 KTID : 4302
    PROC    : db2sysc
    INSTANCE: rzheng               NODE : 000            DB   :
    REORGDB
    APPHDL  : 0-7                  APPID: *LOCAL.rzheng.170130014954
    AUTHID  : RZHENG               HOSTNAME: hotellnx118
    EDUID   : 18                   EDUNAME: db2agent (REORGDB)
    FUNCTION: DB2 UDB, recovery manager, sqlpresr, probe:3280
    DATA #1 : <preformatted>
    Incomplete trasnsactions (either in-doubt or deferred rolllback)
    exist at the end of crash recovery on log stream 0.
    
    But there is no good way to know if the indoubt transaction
    affected the same table as OLR, and more specifically affected
    the same row that OLR might be processing.
    

Local 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

    IT19023

  • 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

    2017-01-30

  • 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"}]

Document Information

Modified date:
29 June 2020