Vermeulen created OPENJPA-2246:
----------------------------------
Summary: when using fetchplans a different entitymanager may
incorrectly eagerly fetch a lazy association
Key: OPENJPA-2246
URL: https://issues.apache.org/jira/browse/OPENJPA-2246
Project: OpenJPA
Issue Type: Bug
Components: jpa, performance
Affects Versions: 2.2.0, 2.1.1
Reporter: Vermeulen
Attachments: openjpalazyeagerfetchplan.zip
Setting a FetchPlan on an entitymanager which loads a certain @OneToMany field
that is marked as lazy and cascade all, can result in a different entityManager
(created by the same factory) to eagerly fetch this field, even if the field is
not in the fetchplan of this different entityManager.
I found two situations where this occurs (each step uses a different
entityManager with a transaction):
1.
* em.merge a new entity (and cascaded related entity) with fetchgroup added
* find entity with no fetchgroup added
-> the lazy-fetched field is incorrectly loaded
2.
* em.persist a new entity (and cascaded related entity) with NO fetchgroup
added
* find entity with fetchgroup added
* find entity with NO fetchgroup added
-> the lazy-fetched field is incorrectly loaded
The weird thing is that persist and merge behave inconsistently - isn't that
great, an inconsistency within an inconsistency? - because switching
persist/merge results in the following situations that work as expected:
1.
* em.persist a new entity (and cascaded related entity) with fetchgroup added
* find entity with no fetchgroup added
-> the lazy-fetched field is a null reference (expected)
2.
* em.merge a new entity (and cascaded related entity) with NO fetchgroup added
* find entity with fetchgroup added
* find entity with NO fetchgroup added
-> the lazy-fetched field is a null reference (expected)
Checking the trace and generated SQL confirms that the field that should not be
fetched is in fact fetched.
I think this is a bug because this is both inefficient and is inconsistent
because I wish my data access to behave predictably.
Note that turning on <property name="openjpa.DetachState" value="fetch-groups"
/> in persistence.xml solves the issues but internally OpenJPA still performs
the eager fetch.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
