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Re: [eclipselink-users] OracleDataSource and threading (?) problems
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This seems to be a bug in the query retry logic not checking if the exception
accessor is null,
>> databaseException.getAccessor().reestablishConnection(this);
This is masking the real exception that you are getting. Please log a bug
for this. Also include in the bug that the original exception should be
logged before the retry.
If you can put a breakpoint or debug in the DatabaseException class, you
should be able to see the real database exception that you are getting.
David Parker-8 wrote:
>
> Thank you very much for the informative response.
>
> We have no kind of container at all - not even tomcat, so the
> DataSource being used is just created by the application, then the
> various jdbc parameters are set on it. Perhaps my problem is with the
> DataSource config rather than with eclipselink? I suspect I am doing
> something ignorant there.....
>
> I am running with eclipselink 1.0.2, btw.
>
> Originally I made the EntityManagerFactory a static, which was working
> OK. I tried making it a local thinking that that was causing the
> problems, but it didn't make any difference.
>
> The code that creates the EntityManagerFactory looks like this:
>
> protected EntityManagerFactory getEntityManagerFactory() {
> if (emf == null || !emf.isOpen()) {
> synchronized (emf_lock) {
> if (emf == null) {
> DataSource ds = getDataSource(emfProps);
> HashMap newprop = new HashMap();
>
> newprop.put(PersistenceUnitProperties.NON_JTA_DATASOURCE, ds);
> emf =
> Persistence.createEntityManagerFactory(puName, newprop);
> }
> }
> }
> return emf;
> }
>
> The getDataSource is simple:
>
> private DataSource getDataSource(Map<String, String> props) {
> try {
> OracleDataSource ds = new OracleDataSource();
>
> //String driver = props.get(DBConstants.JPA_DRIVER_PROP);
> String url = props.get(DBConstants.JPA_URL_PROP);
> String user = props.get(DBConstants.JPA_USER_PROP);
> String password = props.get(DBConstants.JPA_PASSWORD_PROP);
>
> //ds.setDriverType(driver);
> ds.setURL(url);
> ds.setUser(user);
> ds.setPassword(password);
>
> return ds;
>
> } catch (SQLException ex) {
> System.err.println("getDataSoure failed");
> return null;
> }
> }
>
> Here is one of the stacks.
>
> [EL Info]: 2009.02.26 16:23:40.526--UnitOfWork(803339)--Communication
> failure detected when attempting to perform read query outside of a
> transaction. Attempting to retry query.
> java.lang.NullPointerException[EL Warning]: 2009.02.26 16:23:40.526--
> UnitOfWork(1643286)--java.lang.NullPointerException
>
> at
> org
> .eclipse
> .persistence
> .internal.sessions.AbstractSession.executeQuery(AbstractSession.java:
> 1219)
> at
> org
> .eclipse
> .persistence
> .internal.sessions.AbstractSession.executeQuery(AbstractSession.java:
> 1162)
> at
> org
> .eclipse
> .persistence
> .internal
> .indirection
> .QueryBasedValueHolder.instantiate(QueryBasedValueHolder.java:77)
> at
> org
> .eclipse
> .persistence
> .internal
> .indirection
> .QueryBasedValueHolder.instantiate(QueryBasedValueHolder.java:67)
> [EL Info]: 2009.02.26 16:23:40.528--UnitOfWork(803339)--Communication
> failure detected when attempting to perform read query outside of a
> transaction. Attempting to retry query.
> at
> org
> .eclipse
> .persistence
> .internal
> .indirection.DatabaseValueHolder.getValue(DatabaseValueHolder.java:83)
> at
> org
> .eclipse
> .persistence
> .internal
> .indirection
> .UnitOfWorkValueHolder.instantiateImpl(UnitOfWorkValueHolder.java:161)
> at
> org
> .eclipse
> .persistence
> .internal
> .indirection
> .UnitOfWorkValueHolder.instantiate(UnitOfWorkValueHolder.java:230)
> at
> org
> .eclipse
> .persistence
> .internal
> .indirection.DatabaseValueHolder.getValue(DatabaseValueHolder.java:83)
> at
> org
> .eclipse
> .persistence.indirection.IndirectMap.buildDelegate(IndirectMap.java:110)
> at
> org
> .eclipse
> .persistence.indirection.IndirectMap.getDelegate(IndirectMap.java:314)
> at
> org.eclipse.persistence.indirection.IndirectMap.get(IndirectMap.java:
> 301)
>
>
>
> On Mar 2, 2009, at 6:34 PM, Michael O'Brien wrote:
>
>> David,
>> Hi,
>> 1) Yes, EclipseLink is able to run in both container-managed (JTA)
>> and application managed (RESOURCE_LOCAL) modes on any specific full
>> JEE container.
>> Also, using a datasource from Tomcat within an SE JPA application
>> has been tested.
>> Check that you are specifying the jta-data-source/non-jta-data-
>> source property and that you are ok with the fact that the
>> transaction-type defaults to JTA if not specified -when deployed to
>> the server and RESOURCE_LOCAL when on an SE client - this will
>> affect whether the datasource or db properties are used - if they
>> are still specified.
>>
>> For example, for details on setting up an Oracle datasource on
>> WebLogic see...
>>
>> http://wiki.eclipse.org/EclipseLink/Examples/JPA/WebLogic_Web_Tutorial#JNDI_Datasource_Setup
>>
>> Depending on the container that your datasource is running on -
>> you will need extra configuration steps. I assume that your
>> datasource is NOT application managed and that you are using a
>> globally defined datasource (no need for a deploy).
>> For example when targeting Tomcat, you will need to reference the
>> catalina and ds support jars, set your InitialContext factory and
>> prefixes, modify persistence.xml to use a non-jta-data-source and
>> setup the datasource on the server.
>>
>> 2) For the NPE's, post the stacktrace and we will advise.
>> Note: that the default behavior for picking up entities also
>> changes on/off the server and you may need to specify a combination
>> of <class> entries and/or <exclude-unlisted-classes> to pickup or
>> fine tune which entities are picked up.
>>
>> If you would like examples of how to configure your application
>> for a specific server, you may refer to the following examples by
>> server. Most of the examples are using an Oracle JTA datasource.
>> http://wiki.eclipse.org/EclipseLink/Examples/JPA#JPA_Web_Application_Tutorials
>>
>> There are specific instructions for running an application managed
>> datasource for WebLogic
>> http://wiki.eclipse.org/EclipseLink/Examples/JPA/WLS_AppScoped_DataSource
>>
>> and in your particular situation, an example SE JPA app that uses
>> the JTA datasource on Tomcat 6.
>> http://wiki.eclipse.org/EclipseLink/Examples/JPA/Tomcat_Web_Tutorial#Using_JNDI_outside_the_Tomcat_container_for_J2SE_Applications
>>
>> For reference here is a RESOURCE_LOCAL SE JPA app that does not
>> use a datasource.
>> http://dev.eclipse.org/svnroot/rt/org.eclipse.persistence/trunk/examples/org.eclipse.persistence.example.jpa.server.common.ddlgen/
>>
>> Also, be aware that Catalina based server will require a
>> SessionCustomizer that modifies the lookupType on the connector to a
>> String type, see..
>> http://wiki.eclipse.org/EclipseLink/Examples/JPA/Tomcat_Web_Tutorial#Session_Customizer
>>
>> If you post a copy of your persistence.xml as well as your
>> overriding properties and the stack trace/log we will triage this
>> issue.
>> - config details (Application server, Database, EclipseLink
>> version) part of persistence.xml and the logs
>> - persistence.xml
>> - property overrides
>> - application managed *-oracle-ds.xml datasource definition
>> - globally defined datasource definition
>> - stacktrace
>> - some specific example client code if you can (especially if
>> your client is multi-threaded)
>> - EclipseLink [EL] logs on FINEST if possible (both Client and
>> Server if possible)
>>
>> thank you
>> /michael
>>
>> David Parker wrote:
>>> We are using eclipselink in a server application, but there is no
>>> container (j2ee, spring, etc) involved: our persistence environment
>>> is completely application-managed.
>>>
>>> The server has a single static EntityManagerFactory, and each serve
>>> thread gets its own EntityManager.
>>>
>>> This was all working fine when we were passing the low-level jdbc
>>> properties (driver, url, user, password) in the map to create the
>>> EntityManager, but we started having problems
>>> when we tried to switch to using an OracleDataSource (we want to be
>>> able to take advantage of Oracle RAC eventually).
>>>
>>> The code now creates an EntityManager with a single item in the
>>> property map, a pre-constructed DataSource object.
>>>
>>> Unfortunately, we are now seeing random NPE's from deep in the
>>> eclipselink stack. It has all the earmarks of a threading problem,
>>> but all that has changed is the use of the DataSource.
>>>
>>> Is DataSource usage fully supported in a non-containter
>>> environment? Are there additional configuration steps that need to
>>> be taken. Is anybody using OracleDataSource with eclipselink?
>>>
>>> Thanks in advance for any clues.
>>>
>>> ===========================================
>>> David Parker
>>> david@xxxxxxxxxxxxxx
>>> (401) 263-1782
>>>
>>>
>
>
-----
---
http://wiki.eclipse.org/User:James.sutherland.oracle.com James Sutherland
http://www.eclipse.org/eclipselink/
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