Josh Berkus <j...@agliodbs.com> writes: >> You're assuming that we should set up the default behavior to support >> replication and penalize those who aren't using it.
> What's the penalty? Simon just said that there isn't one. I don't know what Simon is thinking, but I think he's nuts. There is is obvious extra overhead in COMMIT: /* * Wake up all walsenders to send WAL up to the COMMIT record * immediately if replication is enabled */ if (max_wal_senders > 0) WalSndWakeup(); which AFAICT is injecting multiple kernel calls into what's not only a hot-spot but a critical section (ie, any error -> PANIC). That's not even considering the extra WAL that is generated when you move up from wal_level = "minimal". That's probably the bigger performance issue in practice. > And there's a difference between saying that I "failed to make a case" > vs. "the cost is too great". I said, and meant, that you didn't make the case at all; you just presumed it was obvious that we should change the defaults to be replication-friendly. I don't think it is. As I said, I think that only a minority of our users are going to want replication. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers