On 2021-02-22 5:43 p.m., Tom Lane wrote: > Michael Brown <michael.br...@discourse.org> writes: >> * is there a knob missing we can configure? > > No. The trouble with sync() is that per POSIX, it only schedules the > writes; there's no way to tell when the work has been done. I see > that Linux offers stronger promises in this department, but I don't > think that's very portableTrue, but as mentioned below we're looking for a > "this makes sense for our environment" switch.
> Moreover, even on Linux there's no way to detect whether any of the writes > failed. Ugh. Presumably those would be noticed when the WAL replays? (I'll admit I'd have to look at the sequence of events and think about it, I don't know offhand.) Oh, syncfs() exists but is Linux-specific, again, darn. > Barring some solution to those problems, we would be unlikely to take > a patch that uses sync() instead of fsync(). I wouldn't dare to propose outright switching to sync() for everyone, but a knob we can turn on to say "use sync (or syncfd()) instead" is what we need, discounting a better solution. -- Michael Brown Civilized Discourse Construction Kit, Inc. https://www.discourse.org/
