Re: Bgwriter behavior

Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > I remember the other difference between 8.0 and pre-8.0. When a backend
> > has to write a block in 8.0, it does a write _plus_ fsync(), while in
> > pre-8.0 it did only a write. There was a proposal to pass backend write
> > information to the background writer so it would know to fsync at
> > checkpoint, but it was decided that backend writing would be rare. I
> > think we have to rethink that assumption.
>
> No, just read the code. The above assertions are all wet.

Oh, I forgot you added that array to pass fsync info.

Shouldn't we send a log message when the array gets full in md.c:

{
if (ForwardFsyncRequest(reln->smgr_rnode, seg->mdfd_segno))
return true;
}

if (FileSync(seg->mdfd_vfd) < 0)
return false;

Seems that could fill up quickly. I see no checking for existing
matching records in the array.

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