Re: checkpoint reliability

> Tom Lane wrote:
> > 
> > Bruce Momjian <pgman@candle.pha.pa.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.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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