On 2014-11-05 08:57:07 +0900, Michael Paquier wrote: > On Tue, Nov 4, 2014 at 10:01 PM, Alvaro Herrera <alvhe...@2ndquadrant.com> > wrote: > > > Michael Paquier wrote: > > > > > I'm still on a -1 for that. You mentioned that there is perhaps no reason > > > to delay a decision on this matter, but IMO there is no reason to rush > > > either in doing something we may regret. And I am not the only one on > > this > > > thread expressing concern about this extra data thingy. > > > > > > If this extra data field is going to be used to identify from which node > > a > > > commit comes from, then it is another feature than what is written on the > > > subject of this thread. In this case let's discuss it in the thread > > > dedicated to replication identifiers, or come up with an extra patch once > > > the feature for commit timestamps is done. > > > > Introducing the extra data field in a later patch would mean an on-disk > > representation change, i.e. pg_upgrade trouble. > > Then why especially 4 bytes for the extra field? Why not 8 or 16?
It's sufficiently long that you can build infrastructure to storing more transaction metadata data ontop. I could live making it 8 bytes, but I don't see a clear advantage. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
