Really disappointing! using JNDI Datasource within Jboss :(

RAPHEAD · **Joined:** Thu Nov 13, 2003 4:12 am **Posts:** 27

Hi,

I'm bloody new to Hibernate but I chose to use Hibernate over ORB...
well even before persisting my first Object I ran into a problem where I don't know how to solve it:

I defined a MySQL datasource in JBoss which I pass to Hibernate via JNDI.
The connection works fine when doing manual SQL statements!
When using Hibernate I run into the following error:

Code:

java.sql.SQLException: Can't call commit when autocommit=true

Fine, there is no possibility in Jboss or in Hibernates config to explicitely make the connection not auto committing

Seqentially I do the following:

Code:

Session s = applicationGlobalData.sessionFactory.openSession();
Transaction t = s.beginTransaction();
         
EntityAddress entityAddress = new EntityAddress();

[...]

s.save(entityAddress)
t.commit(); // flush the Session and commit the transaction
s.close();   

I even ask myself how Hibernate can offer a rollback functionality if it
doesn't care about autocommit?!

What can I do?

T.

gavin · **Posted:** Thu Nov 13, 2003 8:54 am

I'm sorry, I can't quite determine the reason for your post. Were you insulting us, or looking for help? It surely must be one or the other. You couldn't possibly be trying to do both together.....

RAPHEAD · **Joined:** Thu Nov 13, 2003 4:12 am **Posts:** 27

Hi,

Well I'm looking essentially for help because I really don't know what to do now. Ok I could retrieve the con from JNDI by myself, setting it to autocommit=off and passing it to Hibernate via a user defined connection - but that's not really elegant I think.

But what makes me even more afraid is that nobody in this forum seemed to have my problem before which means that the way I use Hibernate - in JSPs - is not really ubiquitous?!

T.

Brannor McThife · **Posted:** Thu Nov 13, 2003 10:06 am

Just an architectural viewpoint on Hibernate, or any other DB connectivity, in JSPs...

I believe it wrong to have any form of database connectivity from your front end. The reasons are varied, but one would be, that if the data on the page is generated from a query in the JSP, then everytime the page is refreshed, the query runs and the database takes a hit. Enough refreshes, and you're going to have some issues.

I would rather recommend, that you introduce a good multi-tiered design, and have your Hibernate saving/loading, etc. in a datalayer, while having a nice, simple servlet interface between your JSPs and the datalayer. This would mean, that your datalayer is totally seperate, and can be reused by whichever front-end you want to use.

You datalayer can be an stateless session bean, or whatever you wish it to be, just I think it is best to keep database calls far away from the front end. :)

-G

RAPHEAD · **Joined:** Thu Nov 13, 2003 4:12 am **Posts:** 27

Hi,

Well in the first step I want to keep things simple and for the few Forms I have: each hit of the submit button will trigger the creation of a new object and the persistence of it (well which doensn't work)
So I don't think there must be another layer inbetween.

Regarding your other thougths:
Does it really make sense to use Hibernate in Conjunction with EJBs?!?
Ok, I did never something with it but I think of it as something like a network transparent Hibernate and when using CMP why would you need Hibernate?!

STILL MY PROBLEM: How do I make my con auto committ = false ?

+

HOW can Hibernate offer roll back if it uses a autocommitted connection - that look braindead to me!!!

T.

Brannor McThife · **Posted:** Thu Nov 13, 2003 10:46 am

RAPHEAD wrote:

Hi,
Does it really make sense to use Hibernate in Conjunction with EJBs?!?
Ok, I did never something with it but I think of it as something like a network transparent Hibernate and when using CMP why would you need Hibernate?!

I didn't say EJBs. I said a Stateless Session bean, that simply performs work, not an EJB that requires CMP or BMP. Besides, I only mentioned that as a possibility.

And for auto commit off...well, do this:

Code:

Session session = sessionFactory.openSession();
session.connection().setAutoCommit(false);
Transasction tx = session.beginTransaction();

Or you can go read section 7.9.4 Exception handling in the Hibernate reference document (Ver 2.0.2)

-G

RAPHEAD · **Joined:** Thu Nov 13, 2003 4:12 am **Posts:** 27

Ok, regarding the xJB stuff

But sorry, I'm really stuck!

HOW can I turn auto committ to off?! HOW?

Hibernate gets my connection like this:

Code:

<hibernate-configuration>
  <session-factory>
    <property name="connection.datasource">java:/mysqlds</property>
    <property name="show_sql">true</property>
    <property name="dialect">net.sf.hibernate.dialect.MySQLDialect</property>
    <property name="use_outer_join">false</property>
   
    <!-- Mapping files -->
    <mapping resource="com/dcx/Customer.hbm.xml"/>
    <mapping resource="com/dcx/EntityAddress.hbm.xml"/>
  </session-factory>
</hibernate-configuration>

And as mentioned: ORB hase a similar mapping/configuration where they allow you to explicitely turn ac=off

Or is my code wrong?!

T.

christian · **Posted:** Thu Nov 13, 2003 11:16 am

Add "relaxAutocommit=true" to your JDBC URL. Read the documentation for the MySQL JDBC driver or try Google. This is not a Hibernate issue.

RAPHEAD · **Joined:** Thu Nov 13, 2003 4:12 am **Posts:** 27

Hi Christian, Thanks yor your reply!

I read through the MySQL Connector j manuals and I thought about AND tried it - no success.

And this maked sense as this setting is only usefule if the driver does not support transactions (mine does)

Quote:

If the version of MySQL the driver connects to does not support transactions, allow calls to commit, rollback and setAutoCommit? (true/false)

And my second question is still not answered:
Suppose Hibernate lives with a autocommitted con and everything works fine.
One day there is an exception and my app issues an tx.rollback().
HOW can Hibernate possibly maintain the transaction when there is no underlying JDBC transaction?
It would have to undo all autocommitted changes which it is not likely to be able of!
Thus it is the job of Hibernate to make sure that the con is not auto committing - or is such a scenario really properly handled by Hibernate?

T.

gavin · **Posted:** Thu Nov 13, 2003 11:46 am

Clearly it is your job to make sure that the appserver datasource that Hibernate uses has autocommit=false. And then rollbacks work correctly.

I am really mystified as to how could be problematic.

RAPHEAD · **Joined:** Thu Nov 13, 2003 4:12 am **Posts:** 27

Hi gavin,

First of all I'm happy, that my thoughts are right!

So the next step is to get this connection not autocommitting
My hope was that in this forum I'll find people who have similar problems but all my searches failed. Then I checked the settings for the Jboss datasources and the Hibernate config - none of them offers the facility to make this setting.
So what can I do?

Why isn't this problem ubiquitous? Is it the case that other JDBC drivers deliver none auto committ conns by default?

T.

gavin · **Posted:** Thu Nov 13, 2003 12:33 pm

Quote:

So the next step is to get this connection not autocommitting

And Christian just told you how to do this, did he not??

gavin · **Posted:** Thu Nov 13, 2003 12:45 pm

P.S. Bill Burke tells me that JBoss disables autocommit by default when a connection is used in the context of a JTA transaction.

christian · **Posted:** Thu Nov 13, 2003 12:56 pm

Actually, the "relaxAutocommit" thing only allows you to commit()/whatever even if autocommit is on.

RAPHEAD · **Joined:** Thu Nov 13, 2003 4:12 am **Posts:** 27

Sorry Gavin,

As I said: Christians approach did NOT work I've tried it even before.

I'm not Using JTA!

Now I tried to include

Quote:

<property name="transaction.factory_class">net.sf.hibernate.transaction.JDBCTransactionFactory
</property>

In my Hibernate config but now it become even worse:

Quote:

ERROR [SessionFactoryImpl] TransactionFactory class not found
java.lang.ClassNotFoundException: net/sf/hibernate/transaction/JDBCTransactionFactory

at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at net.sf.hibernate.util.ReflectHelper.classForName(ReflectHelper.java:268)
at net.sf.hibernate.impl.SessionFactoryImpl.buildTransactionFactory(SessionFactoryImpl.java:463)
at net.sf.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:191)
at net.sf.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:627)
at com.dcx.ApplicationGlobalData.init(ApplicationGlobalData.java:55)
...

Please check:

http://db.apache.org/ojb/deployment.html

under '7.'

You'll see how that they have the facility to nail it to autocommit=false

Seems like a blind alley here...