IBM Support

PM41088: JIRA OPENJPA-1376 DEFECT BACKPORTED TO V7 OPENJPA 1.2.X

Fixes are available

7.0.0.21: WebSphere Application Server V7.0 Fix Pack 21
8.0.0.2: WebSphere Application Server V8.0 Fix Pack 2
8.0.0.3: WebSphere Application Server V8.0 Fix Pack 3
7.0.0.23: WebSphere Application Server V7.0 Fix Pack 23
8.0.0.4: WebSphere Application Server V8.0 Fix Pack 4
7.0.0.25: WebSphere Application Server V7.0 Fix Pack 25
8.0.0.5: WebSphere Application Server V8.0 Fix Pack 5
7.0.0.27: WebSphere Application Server V7.0 Fix Pack 27
8.0.0.6: WebSphere Application Server V8.0 Fix Pack 6
7.0.0.29: WebSphere Application Server V7.0 Fix Pack 29
8.0.0.7: WebSphere Application Server V8.0 Fix Pack 7
8.0.0.8: WebSphere Application Server V8.0 Fix Pack 8
7.0.0.31: WebSphere Application Server V7.0 Fix Pack 31
7.0.0.27: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.33: WebSphere Application Server V7.0 Fix Pack 33
8.0.0.9: WebSphere Application Server V8.0 Fix Pack 9
7.0.0.35: WebSphere Application Server V7.0 Fix Pack 35
8.0.0.10: WebSphere Application Server V8.0 Fix Pack 10
7.0.0.37: WebSphere Application Server V7.0 Fix Pack 37
8.0.0.11: WebSphere Application Server V8.0 Fix Pack 11
7.0.0.39: WebSphere Application Server V7.0 Fix Pack 39
8.0.0.12: WebSphere Application Server V8.0 Fix Pack 12
7.0.0.41: WebSphere Application Server V7.0 Fix Pack 41
8.0.0.13: WebSphere Application Server V8.0 Fix Pack 13
7.0.0.43: WebSphere Application Server V7.0 Fix Pack 43
8.0.0.14: WebSphere Application Server V8.0 Fix Pack 14
7.0.0.45: WebSphere Application Server V7.0 Fix Pack 45
8.0.0.15: WebSphere Application Server V8.0 Fix Pack 15
7.0.0.21: Java SDK 1.6 SR9 FP2 Cumulative Fix for WebSphere
7.0.0.23: Java SDK 1.6 SR10 FP1 Cumulative Fix for WebSphere
7.0.0.25: Java SDK 1.6 SR11 Cumulative Fix for WebSphere Application Server
7.0.0.27: Java SDK 1.6 SR12 Cumulative Fix for WebSphere Application Server
7.0.0.29: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.45: Java SDK 1.6 SR16 FP60 Cumulative Fix for WebSphere Application Server
7.0.0.31: Java SDK 1.6 SR15 Cumulative Fix for WebSphere Application Server
7.0.0.35: Java SDK 1.6 SR16 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.37: Java SDK 1.6 SR16 FP3 Cumulative Fix for WebSphere Application Server
7.0.0.39: Java SDK 1.6 SR16 FP7 Cumulative Fix for WebSphere Application Server
7.0.0.41: Java SDK 1.6 SR16 FP20 Cumulative Fix for WebSphere Application Server
7.0.0.43: Java SDK 1.6 SR16 FP41 Cumulative Fix for WebSphere Application Server

Subscribe

You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

Local fix

  • N/A.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server versions V7.0.0 and V8.0.0 who make  *
    *                  use of the 'allocationSize' when using the  *
    *                  @SequenceGenerator annotation.              *
    ****************************************************************
    * PROBLEM DESCRIPTION: OpenJPA's implementation of the         *
    *                      allocationSize in a @SequenceGenerator  *
    *                      is incorrectly implemented.             *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    The Javadoc for the 'allocationSize' property of the
    @SequenceGenerator annotation defines the 'allocationSize' as
    follows: "The amount to increment by when allocating sequence
    numbers from the sequence."  OpenJPA is using this value as a
    caching value.  That is, when generating a native sequence, an
    SQL like the following my be generated:
    CREATE SEQUENCE entityE2_seq_gen START WITH 1 INCREMENT BY 50
    CACHE 50
    In this SQL statement, OpenJPA is using a 'CACHE 50'
    statement, where the value 50 is the allocationSize.  By using
    caching, OpenJPA is requesting a sequence value from the
    database each time it needs a new sequence.  The database is
    in turning caching sequence values.  This results in extra
    calls to the database.  A more efficient approach would be for
    OpenJPA to cache the sequence value in memory, rather than
    relying on the database, and thus honoring the true meaning of
    'allocationSize'.  Allocating values in memory allows the
    OpenJPA runtime to avoid accessing the database for every
    sequence request.  That is, when 'allocationSize' is set to
    50, OpenJPA will set aside the next 50 numbers each time it
    accesses the sequence, which in turn means it only has to make
    a database trip to get new sequence numbers once every 50
    sequence number requests.  In this case, a sequence similar to
    the following should be generated:
    CREATE SEQUENCE entityE2_seq_gen START WITH 1 INCREMENT BY 50
    

Problem conclusion

  • To enable the code of this fix, please use the
    following JVM system property:
    
    -Dopenjpa.jdbc.DBDictionary=useNativeSequenceCache=false
    
    Or add the following to your persistence.xml file:
    
    <property name="openjpa.jdbc.DBDictionary"
    value="useNativeSequenceCache=false"/>
    
    With this fix, and the above system property, OpenJPA will use
    the 'allocationSize' as intended (i.e. as the increment when
    allocation sequence numbers).
    
    The fix for this APAR is currently targeted for inclusion in
    Service Levels (Fix Packs) 7.0.0.21 and 8.0.0.2 of WebSphere
    Application Server versions 7.0.0 and 8.0.0.
    
    Please refer to the recommended updates page for delivery
    information:
    http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM41088

  • Reported component name

    WEBS APP SERV N

  • Reported component ID

    5724H8800

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-06-08

  • Closed date

    2011-08-30

  • Last modified date

    2011-08-30

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

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

    PM45107

Fix information

  • Fixed component name

    WEBS APP SERV N

  • Fixed component ID

    5724H8800

Applicable component levels

  • R700 PSY

       UP

  • R800 PSY

       UP



Document information

More support for: WebSphere Application Server
General

Software version: 7.0

Reference #: PM41088

Modified date: 30 August 2011