Re: Background writer process

Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)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.

Sorry, I meant sync() is needed for recycling WAL (checkpoint), not for
WAL writes. I assume that's what Shridhar meant, but now I am not sure.

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