Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Shridhar Daithankar wrote:
>> Having fsync for regular data files and sync for WAL segment a comfortable
>> compramise? Or this is going to use fsync for all of them.
> I think we still need sync() for WAL because sometimes backends are
> going to have to write their own buffers, and we don't want them using
> fsync or it will be very slow.
sync() for WAL is a complete nonstarter, because it gives you no
guarantees at all about whether the write has occurred. I don't really
care what you say about speed; this is a correctness point.
regards, tom lane