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IC87146: HANG DURING BUFFERPOOL FLUSH WHEN STMM IS ALTERING A BUFFERPOOL

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • This is a timing issue that can happen when the following
    conditions are true:
    
    1) STMM:
    - altering a buffer pool
    - holding SQLO_LT_SQLB_BufferPool__prevBPDCachingLatch
    - waiting on page cleaner waitpost
    
    Stack trace:
    sqloWaitEDUWaitPost
    sqlbPauseCleanerGroup
    sqlbFinalizeRTBPState
    sqlbAlterBufferPoolAct
    
    2) Page cleaner:
    - waiting on an exclusive latch for page P1
    
    Stack trace:
    sqloltch_notrack
    sqlbClnrAsyncWriteSetup
    sqloDispatchNBlocks
    sqloLioReadWriteNBlocks
    sqlbClnrDispatchSomeAIO
    sqlbClnrWriteSerializeIOList
    sqlbClnrWritePages
    sqlbClnrFindWork
    
    3) Any EDU driving a flush of the dirty list by writing a log
    record, e.g.
    
    a) Index manager adding an index key:
    - holding an exclusive latch on page P2
    - holding SQLO_LT_SQLP_DBCB__add_logspace_sem
    - waiting on SQLO_LT_SQLB_BufferPool__prevBPDCachingLatch
    
    Stack trace:
    sqlbFlushForDLSubset
    sqlbFlush
    sqlbflshConditional
    sqlpgResSpace
    sqlpWriteLR
    sqliakn
    sqlischa
    sqlischa
    
    b) At the same time, another Index manager EDU holding page P1,
    e.g. during runstats processing:
    - holding a shared latch on page P1
    - waiting on a shared latch on page P2
    
    Stack trace:
    sqlbfix
    sqlifix
    sqliFixPageWithChildPtr
    sqlischs
    sqlistat
    sqldIndexStats
    sqlrLocalRunstats
    sqlrrsta
    sqlrr_runstats_DA
    

Local fix

  • The workaround is to disable STMM.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 Version 9.7 Fix pack 8.                       *
    ****************************************************************
    

Problem conclusion

  • First fixed in DB2 Version 9.7 Fix pack 8.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC87146

  • 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

    2012-10-10

  • Closed date

    2013-04-01

  • Last modified date

    2013-04-01

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

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

    IC87456

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSN

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.7

Reference #: IC87146

Modified date: 01 April 2013