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https://issues.apache.org/jira/browse/OPENJPA-265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12507808
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Patrick Linskey commented on OPENJPA-265:
-----------------------------------------
> If datacache is not committed, another transaction does not see
> the loaded data in the data cache and will redundantly query the database
> again.
To follow up: since DataCache.commit() is poorly named, and the data cache is
non-transactional, the data loaded during one transaction will be available to
other transactions immediately. So, the data cache is somewhere between a
READ_COMMITTED and REPEATABLE_READ, semantically. The only exception is if
direct JDBC work is performed on the data source before OpenJPA reads data from
the database; in these situations, cache population may be turned off by
calling OpenJPAEntityManager.setPopulateDataCache(false).
> datacache does not get committed when application commit after a query
> ----------------------------------------------------------------------
>
> Key: OPENJPA-265
> URL: https://issues.apache.org/jira/browse/OPENJPA-265
> Project: OpenJPA
> Issue Type: Bug
> Components: datacache
> Affects Versions: 1.0.0
> Reporter: Daniel Lee
>
> I'm that sure whether this is a bug or not but what is observed is that the
> application commit in the following code does not trigger commit on the
> datacache.
> =============================================================
> EntityManagerFactory emf = Persistence.createEntityManagerFactory("demo");
> EntityManager em = emf.createEntityManager();
> em.getTransaction().begin();
> Customer c = (Customer) em.createQuery("select c from Customer c where
> c.name='Harry Auto'").getSingleResult();
> em.getTransaction().commit();
> =============================================================
> Is this normal because there is no update? It make sense that there is no
> need to flush on the database, but the datacache has been newly loaded with
> the customer "Harry Auto" and the objects that are eagerly related to "Harry
> Auto". If datacache is not committed, another transaction does not see the
> loaded data in the data cache and will redundantly query the database again.
> Is this a bug or working as design? Many thanks.
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