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Subject: RE: Torque Connection pool .. ORA- 01453 - Set Transaction must be
 the
 first statement
To: "Apache Torque Users List" <torque-user@db.apache.org>
Message-ID: 
 <OFBF43700A.402B1286-ONC125714C.004FFA40-C125714C.0050D5C0@seitenbau.net>
From: Thomas Fischer <fischer@seitenbau.net>
Date: Mon, 10 Apr 2006 16:42:55 +0200
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Hi,

I am using the following code:

Connection dbConn = null;
try
{
    dbConn = Transaction.begin(db2.torque.environment));

    ////Do Stuff

    //Commit the transaction (Transaction.commit releases connection back
to the pool)
    Transaction.commit(dbConn);
    dbConn = null;
}
finally
{
    if (connection != null)
    {
        // some error occurred, try to rollback and return connection to
pool
        Transaction.safeRollback(dbConn);
        dbConn = null;
    }
}

It is safer to use a finally block than a catch block. In some ugly cases,
you get errors and not exceptions, and they are not caught by
catch(exception). Also, the finally block works even if you return inside
the block.

I have also written some docs about this, but I have forgotten to commit it
:-(.

    Thomas


Jim Caserta <smoothie_jc@yahoo.com> schrieb am 10.04.2006 15:27:37:

> Thomas,
>
> I was reading through this thread and I wantwed to be
> sure what you are saying. Is the example below the way
> we should be handling transactions? Thanks!
>
>
> Connection dbConn = null;
> try {
>       dbConn = Transaction.begin(db2.torque.environment));
>
>       ////Do Stuff
>       //Commit the transaction (Transaction.commit, should
> release connection back to the pool
>       Transaction.commit(dbConn);
>       Transaction.safeRollback(dbConn);
>    }catch(TorqueException e){
>       try {
>          Transaction.rollback(dbConn);
>       } catch (TorqueException e1) {
>          Transaction.safeRollback(dbConn);
>       }
>       }finally {
>          if(!dbConn.isClosed()){
>             Torque.closeConnection(dbConn);
>          }
>       }
>
>
> --- Thomas Fischer <tfischer@apache.org> wrote:
>
> > Using commits/rollbacks without explicitly startung
> > a connection may look
> > unclean but does not cause any problems in practice
> > (at least none known
> > to me). The problem described seems to be the other
> > way round: there is no
> > rollback/commit where should be one.
> >
> >    Thomas
> >
> > On Mon, 27 Mar 2006, Greg Monroe wrote:
> >
> > > I did a quick wander thru the Torque code and saw
> > one thing
> > > that did not look right to me.  Here's some
> > background first:
> > >
> > > All of the Torque Transaction handling is built on
> > the
> > > Transaction class. This is used primarily by the
> > BasePeer
> > > methods like doUpdate(Criteria) and the like.
> > >
> > > These methods are the ones that automatically wrap
> > the
> > > DB actions as a transaction with rollback.
> > >
> > > The first thing that didn't look right to me was
> > that the
> > > Transaction.beginOptional(dbName, useTransaction)
> > method
> > > is called with the useTransaction arg set to the
> > value of
> > > criteria.isUseTransation().  This value is set to
> > false by
> > > default.
> > >
> > > So, it seems that if you don't set this explicitly
> > on your
> > > Criteria, you are not using really using
> > transactions but
> > > you still have the Transaction try/catch code with
> > commits and
> > > rollbacks.
> > >
> > > Shouldn't the default for isUseTransactions() be
> > true and/or
> > > the code handle the false condition without
> > calling the
> > > extra transaction methods?
> > >
> > >
> > >> -----Original Message-----
> > >> From: vivek sar [mailto:vivextra@gmail.com]
> > >> Sent: Saturday, March 25, 2006 4:44 AM
> > >>
> > >> Thanks Thomas for detailed explanation. I haven't
> > dig into
> > >> the Torque or dbcp code to tell exactly where the
> > fault lies.
> > >> The way I understand is that the db starts the
> > transaction on
> > >> your behalf if you don't start one. In case that
> > transaction
> > >> fails it will try to rollback. The problem I've
> > stated is
> > >> while the transaction is rolling back the same
> > connection is
> > >> somehow being used by other query and that's
> > causing the
> > >> "ORA-01453" and hanging of the connection.
> > >>
> > >>  I would think it's a problem with dbcp if not
> > torque as dbcp
> > >> is the one that handles the connection pool. I
> > couldn't find
> > >> much on the dbcp commons mailing-archiving list,
> > but found
> > >> tons of similar problems reported by torque
> > users, so I think
> > >> most of the people do assume it's a Torque
> > problem or
> > >> somewhere related to it.
> > >>
> > >>  Yes, if I do handle the transaction myself I
> > don't get into
> > >> this issue, but still the connection pool should
> > handle the
> > >> transactions/connections gracefully if it's
> > starting one on
> > >> your behalf.
> > >>
> > >>  I've the autocommit turned on (by default), so
> > it shouldn't
> > >> be problem with that either.
> > >>
> > >> I am still waiting for the right answer where
> > exactly the
> > >> problem lies -
> > >> 1) How do I get ORA-01453 if I am not starting
> > the transaction myself
> > >> 2) Why the connection hangs after the ORA-01453
> > >>
> > >> Thanks,
> > >> -vivek
> > >>
> > >
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