On Wed, Jul 04, 2007 at 10:10:08AM -0400, Jan Wieck wrote:
> seems pretty deterministic, doesn't it? But the result of it depends on 
> the exact commit order and the transaction isolation level. We don't 
> capture the commit order of single transactions, nor do we care for it 
> anywhere in the Slony-I logic.

I think this is key.  The current arrangement solves the problem
where the visibility rules as they were in force on the origin are
followed while applying on the replica.  You're going to need to do
quite a bit of theoretical work here to show that the agreeable order
rules are followed in any grouping approach you take.  Please see the
original concept paper on this exact point.  MVCC is hard.

A

-- 
Andrew Sullivan  | ajs at crankycanuck.ca
However important originality may be in some fields, restraint and 
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great many others.   --Alain de Botton