A function would be perfect!  A String would work for SymmetricDS.
The value needs to be unique across database restarts.  The faster the
better.  We use it to track changes that need to be 'synchronized'
atomically.  I am really looking for the equivalent of
DBMS_TRANSACTION.local_transaction_id(false) on Oracle.  I would think
the name could be as simple as TRANSACTION_ID() ??

Thank you.

On Feb 6, 2:10 pm, Thomas Mueller <[email protected]>
wrote:
> Hi,
>
> > I am currently implementing an H2 'database dialect' for SymmetricDS
> > (www.symmetricds.org).    I am trying to figure out the best way to
> > access a 'transaction id' from an H2 trigger.  The following is the
> > Java code I have come up with.  Does anybody have suggestions for
> > improvements (or more likely can they poke holes in my approach)?
>
> >    protected String getTransactionId(Connection c) {
> >            JdbcConnection con = (JdbcConnection) c;
> >            Session session = (Session) con.getSession();
> >            return StringUtils.leftPad(Integer.toString(session.getId
> > ()), 3, "0") + "-"
> >                    + session.getFirstUncommittedLog() + "-" +
> > session.getFirstUncommittedPos();
> >    }
>
> There is currently no good way to do that. How unique does the
> transaction id need to be? I mean, is it a problem if the id starts
> from 0 when you restart the application? Is there a sort requirements
> (larger transaction ids means later)?
>
> Your solution doesn't work for remote connections. I suggest I add a
> SQL system function that returns the current transaction id. What is
> your preferred function name?
>
> Is a String good enough, or is a byte array better? How fast does it
> need to be?
>
> Regards,
> Thomas
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