PostgreSQL version 8.3 got "lazy xid allocation", I think it is no
longer desirable
for slony to issue ROLLBACK for its read-only queries.

I think it might be very helpful to have a switch which could turn off
this feature. [1]

Just an idea.

   Regards,
     Dawid Kuroczko

[1]: Well, even without lazy xids, I think such a parameter would be
useful.  If you
are monitoring the rollback counter of your databse, you can spot the
application
problem which is not solved elsewhere.  Now if your database is rollbacking most
every second, you are more likely to not notice it.  I know it has a
price with it,
but sometimes it is worth it.  By the way, how much do we really gain by
rollbacking?  I am curious if they really save our day. :-)