Re: Possible Commit Syntax Change for Improved TPS

Christopher Browne <cbbrowne(at)acm(dot)org> writes:
> In the last exciting episode, seunosewa(at)inaira(dot)com (Seun Osewa) wrote:
>> So I want to ask, "what is databases have a 'COMMIT NOSYNC;' option?"

> Another possibility in this would be to have not one, but TWO
> backends.
> One database, on one port, is running in FSYNC mode, so that the
> "really vital" stuff is sure to get committed quickly. The other, on
> another port, has FSYNC turned off in its postgresql.conf file, and
> the set of "untrusted" files go there.

They would have in fact to be two separate installations (not two
databases under one postmaster). There is no way to make some
transactions less safe than others in a single installation, because
they're all hitting the same WAL log, and potentially modifying the
same disk buffers to boot. Anyone's WAL sync therefore syncs everyone's
changes-so-far.

regards, tom lane