On Sat, Mar 19, 2011 at 4:29 AM, Simon Riggs <si...@2ndquadrant.com> wrote: > On Fri, 2011-03-18 at 20:19 +0100, Markus Wanner wrote: >> Simon, >> >> On 03/18/2011 05:19 PM, Simon Riggs wrote: >> >>> Simon Riggs<si...@2ndquadrant.com> wrote: >> >>>> In PostgreSQL other users cannot observe the commit until an >> >>>> acknowledgement has been received. >> >> On other nodes as well? To me that means the standby needs to hold back >> COMMIT of an ACKed transaction, until receives a re-ACK from the master, >> that it committed the transaction there. How else could the slave know >> when to commit its ACKed transactions? > > We could do that easily enough, actually, if we wished. > > Do we wish?
No. I'm not sure what's the problem with seeing from the standby the data which is not visible on the master yet? And, I'm really not sure whether that problem can be solved by making the data visible on the master before the standby. If we really want to see the consistent data from each node, we should implement and use a cluster-wide snapshot as well as Postgres-XC does. Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
