Re: Should pg_stat_bgwriter.buffers_backend_fsync be removed?

Peter Geoghegan <pg@heroku.com> writes:
> Backend fsyncs are theoretically still possible after the fsync
> request queue compaction patch (which was subsequently back-patched to
> all supported release branches). However, I'm reasonably confident
> that that patch was so effective as to make a backend fsync all but
> impossible.

What's your evidence for that claim?
        regards, tom lane