PK75612: UNNEEDED SQL PUSHDOWNS IN BIDIRECTIONAL ONE-TO-MANY EAGER FETCH.

Fixes are available

APAR status

Closed as program error.

Error description

Entities having bidirectional OneToMany EAGER fetch type would
hit this performance problem.  Especially for find-all kind of
JPQL queries.The number of extra SQLs we pushdown is almost
equals to  n*m (where n is number of the entities that require
the OneToMany relation eagerly loaded with m members in each
collection).

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  All users of WebSphere Application Server   *
*                  V7.0                                        *
****************************************************************
* PROBLEM DESCRIPTION: When the many side of a one-to-many     *
*                      eager bidirectional relationship is     *
*                      being populated, unnecessary SQL is     *
*                      generated.                              *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
A publisher entity has a one-to-many bidirectional
relationship to a magazine entity. In the process of
populating the publisher, the collection of magazines is also
populated (because of the EAGER specification for the
FetchType property). The SQL that retrieves magazine records
from the database contains additional backward join clauses,
to join the magazine to the publisher. Some of these joins are
not needed, since the information for publisher has already
been retrieved. The additional joins cause performance
degradation.

Problem conclusion

When the many side is being populated, if the one
side has already been initialized, then it's object id is
stored in the mappedByValue() for the many side's inverse
mapping. This ensures that no additional join clauses to fetch
the one side data are introduced.

The fix for this APAR is currently targeted for inclusion in
fixpack 7.0.0.3. 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
PK75612
Reported component name
WEBSPHERE APP S
Reported component ID
5724J0800
Reported release
700
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2008-11-13
Closed date
2009-02-26
Last modified date
2009-02-26

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
WEBSPHERE APP S
Fixed component ID
5724J0800

Applicable component levels

R700 PSY
UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
23 October 2021

Tips

PK75612: UNNEEDED SQL PUSHDOWNS IN BIDIRECTIONAL ONE-TO-MANY EAGER FETCH.

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

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

Fixed component ID

Applicable component levels

R700 PSY

Document Information

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