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IT05114: SLOW PERFORMANCE WHEN TARGET POOL IS COLLOCATED BY GROUP

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APAR status

  • Closed as program error.

Error description

  • When the target storage pool is collocated by group, any
    allocations into that storage pool may have slow performance.
    The majority of time
    is spent on DB2 Reg Exec operations. The number of this DB2
    operations for each aggregate is equal to the number of nodes
    in the same collocation group. If the number of nodes in the
    collocation group is large, the number of DB2 Reg Exec is large
    which causes performance degradation.
    
    This will affect any process that allocates data into a storage
    pool which includes: backup, archive, move data, migration,
    reclamation, backup stgpool.
    
    The following call stack is a sample call stack for this issue:
    
    Thread 123831, Parent 302: psSessionThread, Storage 8286618,
    AllocCnt
    38408 HighWaterAmt 15027091
    
     tid=3d7b7, ptid=322e, det=1, zomb=0, join=0, result=0,
    sess=80719
      Stack trace:
    
        0x090000000010b0c4 recv
    
        0x0900000019a55574
    
    tcprecv__FP17SQLCC_COMHANDLE_TiPcT2UsT5P21SQLCC_TCPCONNHANDLE_TP
    12SQLCC
    COND_TUiPi
    
        0x0900000018c362cc
    
    sqlcctcprecv__FP17SQLCC_COMHANDLE_TP12SQLCC_COND_T
    
        0x090000001994b3d4 sqlccrecv
    
        0x090000001966be74 sqljcReceive__FP10sqljCmnMgr
    
        0x0900000019636afc
    
    sqljrDrdaArOpen__FP14db2UCinterfaceP15db2UCCursorInfo
    
        0x0900000019592080
    csmOpen__FP14db2UCinterfaceP15db2UCCursorInfo
        0x09000000195925c8
    
    CLI_sqlOpen__FP17CLI_STATEMENTINFOP19CLI_ERRORHEADERINFO
    
        0x090000001964a114
    
    SQLExecute2__FP17CLI_STATEMENTINFOP19CLI_ERRORHEADERINFO
    
        0x0900000019646cd8 SQLExecute
    
        0x0000000100136d40 tbRegExecEx
    
        0x00000001009c2148 ExtractVolidFromRegisteredSQL
    
        0x00000001009c156c GetIncludeVolListEx
    
        0x00000001009bdbdc GetIncludeVolList
    
        0x00000001009bb390 AfAllocSpace
    
        0x00000001009baecc AfCreate
    
        0x0000000100603e98 CreateBitfile
    
        0x000000010060127c bfCreate
    
        0x0000000100787c44 CreateBitfile
    
        0x0000000100764088 SmDoBackInsNormEnhanced
    
        0x000000010075a0b4 SmNodeSession
    
        0x000000010074bf24 HandleNodeSession
    
        0x000000010073d934 smExecuteSession
    
        0x0000000100167c98 psSessionThread
    
        0x000000010000cae0 StartThread
    
    Note that the thread name and the bottom part of the call stack
    can be completely different, the important part of the call
    stack is:
    
        0x00000001009c2148 ExtractVolidFromRegisteredSQL
    
        0x00000001009c156c GetIncludeVolListEx
    
        0x00000001009bdbdc GetIncludeVolList
    
        0x00000001009bb390 AfAllocSpace
    
    This is showing that we are getting a list of candidate volumes
    for an allocation request into the storage pool.
    
    In addition, the following can be seen in the performance data
    for this thread:
    
    DB2 Reg Exec     1033 1533.638    1.485    0.000  508.607
    
    The number of DB2 Reg Exec should be a small multiple of the
    number of volume allocation requests that this thread made in
    this snapshot interval.  In this case we can see the value is
    significantly larger.
    
    Tivoli Storage Manager Versions Affected:
    Tivoli Storage Manager Server v7.1
    
    Initial Impact:
    Medium
    
    Additional Keywords:
    TSM; migrate
    

Local fix

  • Local Fix:
    Turn off collocation of target pool
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All Tivoli Storage Manager server users.                     *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See ERROR DESCRIPTION.                                       *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Apply fixing level when available. This                      *
    * problem is currently projected to be fixed                   *
    * in level 7.1.3. Note that this is subject                    *
    * to change at the discretion of IBM.                          *
    ****************************************************************
    

Problem conclusion

  • This problem was fixed.
    Affected platforms: AIX, HP-UX, Solaris, Linux and Windows.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT05114

  • Reported component name

    TSM SERVER

  • Reported component ID

    5698ISMSV

  • Reported release

    71W

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2014-10-23

  • Closed date

    2015-02-17

  • Last modified date

    2015-09-03

  • 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

    TSM SERVER

  • Fixed component ID

    5698ISMSV

Applicable component levels

  • R71A PSY

       UP

  • R71H PSY

       UP

  • R71L PSY

       UP

  • R71S PSY

       UP

  • R71W PSY

       UP



Document information

More support for: Tivoli Storage Manager

Software version: 7.1.3

Reference #: IT05114

Modified date: 03 September 2015