Hi, On 03/18/2011 02:40 PM, Kevin Grittner wrote: > Then the only thing you would consider sync replication, as far as I > can see, is two phase commit
I think waiting for the ACK before actually making the changes from the transaction visible (COMMIT) would suffice for disallowing such an inconsistency to manifest. But obviously, MySQL decided it's not worth doing that, as it's such a rare event and a short period of time that may show inconsistencies... > people's needs. The guarantee that some people are looking for is > that a successful commit means that the data has been persisted on > two separate servers. Well, MySQL's semi-sync also seems to guarantee that WRT the client confirmation. And transactions always appear committed *before* the client receives the COMMIT acknowledgement, due to the time it takes for the ACK to arrive at the client. It's just the commit *before* receiving the slave's ACK, which might make a transaction visible that's not durable, yet. But I guess that simplified implementation for them... Regards Markus Wanner -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
