[JDBC driver] DBConstraint violation within transaction block leaves connection in indeterminate state

Hi,

I'm running Postgresql 7.1.2 server on RedHat Linux 7.1 (intel) and connect=
ing using JDBC on Windows NT using jdbc7.1-1.2.jar.

The sequence to reproduce the error is as follows:

1. Create database with various constraints (such as UNIQUE, CHECK, etc).
2. Queue 3 or more INSERT / UPDATE statements on a connection with AutoComm=
it turned off.
3. Let the second statement violate a structural constraint (as specified i=
n 1. above)
4. Commit the transaction
5. Now issue any database query statement against the same connection.
=3D=3DBUG: the query that is executed is the third queued statemenet, which=
 does not return any results

To work-around this, trap the SQLException that is thrown within the transa=
ction block and call connection.rollback().

My understanding in relation to transaction blocks is that if the transacti=
on fails, then the database is not updated. Furthermore, I would also expec=
t that the connection is left in an equally clean state, but this clearly i=
s not the case. If the transaction fails, then surely all statements queued=
 should be considered expired, and let the caller re-queue them as part of =
error recovery.

Please clarify whether my expected behaviour is correct, and if this is a b=
ug, then it needs to be addressed.

Many thanks
Adrian Geissel