Re: checkpoint reliability

> Tom Lane wrote:
> >
> > Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > > I was wondering, when we start to reuse a WAL file, do we know that all
> > > dirty buffers modified in that WAL file have been flushed to disk?
> >
> > Yes. At least two checkpoints ago, in fact.
>
> Isn't the following what Bruce asked ?
>
> /*
> * mdsync() -- Sync storage.
> *
> */
> int
> mdsync()
> {
> sync();
> if (IsUnderPostmaster)
> sleep(2);
> sync();
> return SM_SUCCESS;
> }

Oh, yes. That is it. I couldn't find out how we were sure our pages
that we had written to the kernel were actually on disk before we
started reusing the WAL files.

Thanks.

--
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