IC94707: ONLINE BACKUP MIGHT BLOCK TRANSACTIONS THAT ARE DOING COMMIT.

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • BACKUP DATABASE command prunes the "table space change history
    file (DB2TSCHG.HIS)", right before the end of the BACKUP
    DATABASE command. When an ONLINE BACKUP is pruning the
    DB2TSCHG.HIS file, it might block applications that are doing
    COMMIT at the same time.
    The problem happens to "full" BACKUP only, as opposed to
    "tablespace-level" BACKUP.
    
    To identify the problem, please issue "db2pd -stack all" command
    to generate stack files.
    
    Stack file of the BACKUP coordinator agent will have content
    similar to the following:
    ===========================================
    <StackTrace>
    sqlpPruneTsChgHistoryFile
    sqluhPruneDatabaseHistoryOnePass
    sqluhPruneDatabaseHistory
    sqlubupHistoryFile
    sqlubcka
    </StackTrace>
    
    <LatchInformation>
    Holding Latch type:
    (SQLO_LT_SQLP_LOGTS_LOG_FILES_INFO__latchLogTsInfo)
    </LatchInformation>
    ===========================================
    It's holding the
    'SQLO_LT_SQLP_LOGTS_LOG_FILES_INFO__latchLogTsInfo' latch which
    is being waited by EDU named 'db2logts':
    ===========================================
    <StackTrace>
    sqloXlatchConflict
    sqlpDirtyPoolHandler
    sqloEDUEntry
    </StackTrace>
    
    <LatchInformation>
    Waiting on latch type:
    (SQLO_LT_SQLP_LOGTS_LOG_FILES_INFO__latchLogTsInfo)
    </LatchInformation>
    ===========================================
    
    Meanwhile, all agents that are doing COMMIT are stuck in one of
    the following stack traces:
    ===========================================
    sqloXlatchConflict
    sqlpUploadDirtyPoolEntry
    sqlpUploadDirtyPoolEntry
    sqlpEndUowRuntime
    sqlpxcm1 (or 'sqlpxcm2')
    
    or
    
    sqloSpinLockReleaseConflict
    sqlpUploadDirtyPoolEntry
    sqlpUploadDirtyPoolEntry
    sqlpEndUowRuntime
    sqlpxcm1 (or 'sqlpxcm2')
    
    or
    
    ossSleep
    sqlorest
    sqlpUploadDirtyPoolEntry
    sqlpUploadDirtyPoolEntry
    sqlpEndUowRuntime
    sqlpxcm1 (or 'sqlpxcm2')
    ===========================================
    
    If the DB2TSCHG.HIS file is big in size and too many entries
    need to be retained in the file (which is controlled by database
    configuration parameter named REC_HIS_RETENTN), the BACKUP
    DATABASE command might take a long time in pruning the
    DB2TSCHG.HIS file. As a result, there is a good chance to hit
    the problem.
    
    The fix of the APAR will improve the performance of pruning
    DB2TSCHG.HIS file, hence minimize the chance of hitting the
    problem.
    

Local fix

  • 1) Set DB2 registry variable DB2_COLLECT_TS_REC_INFO=OFF to stop
    updating DB2TSCHG.HIS file, which can definitely avoid the
    problem.
    2) Set a small value to parameter REC_HIS_RETENTN.
    3) Prune the DB2TSCHG.HIS file manually by "PRUNE HISTORY"
    command to reduce the size of the file.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All users of version 9.7 on Linux, Unix and Windows          *
    * platforms.                                                   *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Update to DB2 LUW Version 9.7 Fix Pack 9 or higher levels.   *
    ****************************************************************
    

Problem conclusion

  • First fixed in DB2 LUW Version 9.7 Fix Pack 9.
    

Temporary fix

  • 1) Set DB2 registry variable DB2_COLLECT_TS_REC_INFO=OFF to stop
    updating DB2TSCHG.HIS file, which can definitely avoid the
    problem.
    2) Set a small value to parameter REC_HIS_RETENTN.
    3) Prune the DB2TSCHG.HIS file manually by "PRUNE HISTORY"
    command to reduce the size of the file.
    

Comments

APAR Information

  • APAR number

    IC94707

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-08-07

  • Closed date

    2014-05-09

  • Last modified date

    2014-05-09

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

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

    IC96356 IC96682

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSN

       UP



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Document information


More support for:

DB2 for Linux, UNIX and Windows

Software version:

9.7

Reference #:

IC94707

Modified date:

2014-05-09

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