Re: PostgreSQL JDBC and WebLogic

The jdbc driver does the "right" thing according to the jdbc spec.
Calling setAutoCommit(false) on the connection will cause the driver to
issue an implicit 'begin' after every call to rollback() or commit().
Therefore all statements executed will end up running inside a single
transaction which is ended by a commit() or rollback() call (which then
starts the next transaction).

thanks,
--Barry

Paulo Merson wrote:

> I am migrating a database and applications from Oracle to PostgreSQL
> 7.1.
> We have a J2EE applications consisting of JSP, servlets and EJB that is
> executed in BEA WebLogic. We have successfully configured a WebLogic
> connection pool to access Postgres using the JDBC driver
> (jdbc7.1-1.3.jar) and the application runs perfectly.
>
> However, I have a concern based on Postgres behavior regarding
> transactions. I would be deeply grateful if you could tell me if the
> following is correct:
>
> - Postgres always issue a commit after each user statement, unless you
> submit a "begin" statement to demarcate the beginning of a transaction.
> There is no way to disable the "auto-commit" behavior; we need to submit
> "begin" in every transaction that embodies more than one statement.
>
> Further, considering that Postgres doesn't have a configuration
> parameter to disable "auto-commit", what would be the effect of the
> following piece of Java code?
>     ...
>     Connection con;
>     con.setAutoCommit(false);
>     ...
>
> After the "commit" that follows this piece of code, does the
> "auto-commit" remain disabled for other transactions using the same
> connection? What about transactions created by other connections?
>
> My concern is that WebLogic, like any J2EE app server, has a transaction
> service that interfaces with resource managers (i.e. PostgreSQL). Thus,
> if one uses Oracle or Cloudscape or DB2 (not to mention others that I'm
> not familiar), your code typically does not have
> "con.setAutoCommit(false)"; it's up to the app server transaction
> service to control transactions according to some hints you give it - if
> you're familiar with J2EE, these hints would be the transaction
> attributes in the DDs for BMT components.
> It seems that I'll need to insert this "con.setAutoCommit(false)" in the
> beginning of every transaction; and it seems that this JDBC statement
> translates to a Postgres "begin" statement. Could you please clarify
> this point?
>
> Paulo Merson
> Summa Technologies - www.summa-tech.com
>
>
>
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