duplicate entries in db

[plewis66]

For something we really believe shouldn't happen...

We have an entity, and a process that runs in batches creating instances of this entity.

The process checks to see whether anything in the dB should cause a conflict with the entity about to be created - not on the primary key, but on the value in a (string) field.

However, the process is resulting in rows in the database with duplicate values in this string field.

Now we can probably get round this by changing the schema a bit, but I am interested to know how this could be happening.

Any thoughts would be helpful. We are using TRANSACTION_READ_COMMITTED, and the process has transaction-attribute required, the entity transaction-attribute supports. The process component (session bean) is called repeatedly by a Servlet.

Ta

Phil

[adrian.brock]

Look at the javadoc for javax.sql.Connection

If I understand what you are doing,
you want TRANSACTION_SERIALIZABLE
to stop another transaction inserting a record
after your select statement that would have been
retrieved.

All you are doing, is not seeing uncommitted records.

Regards,
Adrian

[plewis66]

Thanks for that....erm...

Could you tell me where I set it?

I have set it in jboss.jcml in XADataSourceLoader>>TransactionIsolation, but I a still experiencing the same problem.

In Weblogic, this is set in weblogic-ejb-jar.xml on a per bean basis, but there does not seem to be an equivalent setting available in jboss.xml.

Thanks

Phil

[adrian.brock]

Does your database support that isolation level?

Try using getTransactionIsolation() to see what
level of isolation you get.

Regards,
Adrian