Re: TOAST performance (was Re: [GENERAL] Delete Performance)

> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > Is it because we take a snapshot of the page before we write it in case
> > we only write part of the page?
>
> AFAIR, the partial-page-write problem is the entire reason for doing it.
> If we could be certain that writes to datafile pages were atomic, we'd
> not need this.
>
> Of course we can't be certain of that. But I'm wondering if there isn't
> a cheaper solution.

I have added these TODO items to summarize this discussion:

* Reduce number of pre-page WAL writes; they exist only to gaurd against
partial page writes
* Turn off pre-page writes if fsync is disabled (?)

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