PM74874: UNEXPECTED SPACE GROWTH OF PBG UTS TABLE SPACE, WHEREBY ONLY 1 PAGE PER SEGMENT WAS ACTUALLY USED.

A fix is available

Subscribe

You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Unexpected space growth of PBG UTS tablespace with SEGSIZE=64,
    whereby only 1 page per segment was actually used. This apar
    applies to any defined SEGSIZE for PBG, but the growth is very
    noticeable with SEGSIZE=64. Rapid growth was also seen with PBG
    Member Cluster and will be addressed in this apar.
    

Local fix

  • Reduce the SEGSIZE and increase REORG frequency.
    
    
    
    
    
    
    
    
    
    
    
    
    *
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All DB2 10 z/OS users of Partition By        *
    *                 Growth table spaces with and without         *
    *                 MEMBER CLUSTER.                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: When using PBG table spaces it is       *
    *                      possible to see only the first page     *
    *                      in a segment being used before going    *
    *                      to another new segment.  This caused    *
    *                      rapid growth of the table space.        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    In the non MEMBER CLUSTER case a small timing window could cause
    getting a new segment to occur multiple times consecutively,
    which would result in just the first page of the new segment to
    be used.  This would then leave the rest of the segment empty.
    
    In the MEMBER CLUSTER case, during an UPDATE operation if there
    was no room for the newly updated record in its current
    partition, it would then search the first Space Map page of the
    next partition before it asked for a new segment.  When multiple
    updates occur at the same time, each update would ask for a new
    segment resulting in only the 1st page of each segment being
    used.
    

Problem conclusion

  • In the non MEMBER CLUSTER case the timing window has been
    shortened so that this scenario is less likely to occur.
    
    In the MEMBER CLUSTER case after searching the 1st Space Map
    page we will search the last segment before asking for a new
    segment.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM74874

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    A10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-10-11

  • Closed date

    2013-06-17

  • Last modified date

    2013-08-02

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

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

    UK95206

Modules/Macros

  • DSNISGNS DSNISGSC DSNISUPI
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • RA10 PSY UK95206

       UP13/07/03 P F307

Fix is available

  • Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.



Rate this page:

(0 users)Average rating

Document information


More support for:

DB2 for z/OS

Software version:

A10

Reference #:

PM74874

Modified date:

2013-08-02

Translate my page

Machine Translation

Content navigation