On Sat, Mar 19, 2011 at 12:07 AM, Robert Haas <robertmh...@gmail.com> wrote: > On Fri, Mar 18, 2011 at 10:55 AM, Greg Stark <gsst...@mit.edu> wrote: >> On Thu, Mar 17, 2011 at 5:46 PM, Robert Haas <robertmh...@gmail.com> wrote: >>> What makes more sense to me after having thought about this more >>> carefully is to simply make a blanket rule that when >>> synchronous_replication=on, synchronous_commit has no effect. That is >>> easy to understand and document. >> >> For what it's worth "has no effect" doesn't make much sense to me. >> It's a boolean, either commits are going to block or they're not. >> >> What happened to the idea of a three-way switch? >> >> synchronous_commit = off >> synchronous_commit = disk >> synchronous_commit = replica >> >> With "on" being a synonym for "disk" for backwards compatibility. >> >> Then we could add more options later for more complex conditions like >> waiting for one server in each data centre or waiting for one of a >> certain set of servers ignoring the less reliable mirrors, etc. > > This is similar to what I suggested upthread, except that I suggested > on/local/off, with the default being on. That way if you set > synchronous_standby_names, you get synchronous replication without > changing another setting, but you can say local instead if for some > reason you want the middle behavior. If we're going to do it all with > one GUC, I think that way makes more sense. If you're running sync > rep, you might still have some transactions that you don't care about, > but that's what async commit is for. It's a funny kind of transaction > that we're OK with losing if we have a failover but we're not OK with > losing if we have a local crash from which we recover without failing > over.
I'm OK with this. 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