From: pgsql-hackers-ow...@postgresql.org > [mailto:pgsql-hackers-ow...@postgresql.org] On Behalf Of Robert Haas > On Thu, Nov 17, 2016 at 10:08 PM, Craig Ringer <cr...@2ndquadrant.com> > wrote: > > We can and probably should have both. > > > > If the server tells us on connect whether it's a standby or not, use that. > > > > Otherwise, ask it. > > > > That way we don't pay the round-trip cost and get the log spam when > > talking to newer servers that send us something useful in the startup > > packet, but we can still query it on older servers. Graceful fallback. > > > > Every round trip is potentially very expensive. Having libpq do them > > unnecessarily is bad. > > True, but raising the bar for this feature so that it doesn't get done is > also bad. It can be improved in a later patch.
I thought you are very strict about performance, so I hesitate to believe you forgive the additional round trip. libpq failover is a new feature in v10, so I think it should provide the best user experience for v10 client+server users from the start. If the concern is the time for development, then support for older releases can be added in a later patch. There are still several months left for v10. Why don't we try the best? Could you share the difficulty? Regards Takayuki Tsunakawa -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers