Re: BUG #10675: alter database set tablespace and unlogged table

On 2014-06-20 23:34:36 +0530, Pavan Deolasee wrote:
> On Wed, Jun 18, 2014 at 7:49 PM, Andres Freund <andres(at)2ndquadrant(dot)com>
> wrote:
>
> > On 2014-06-18 09:45:46 -0400, Tom Lane wrote:
> > > Andres Freund <andres(at)2ndquadrant(dot)com> writes:
> > > > On 2014-06-18 16:15:47 +0530, Pavan Deolasee wrote:
> > > I'm with Pavan on this one: it's *not* a good thing that manually issued
> > > checkpoints skip unlogged tables. That's surprising, possibly dangerous,
> > > and no case whatsoever has been made that anyone sees it as an important
> > > performance benefit.
> >
> > I don't understand what dangers it has? Any unclean shutdown resets all
> > unlogged tables.
> >
> >
> Looks like there is no agreement on this. I agree with Andreas that given
> the current mechanism of truncating unlogged relations at the end of redo
> recovery, there is no danger in not flushing the dirty buffers belonging to
> unlogged relation at a normal checkpoint. Having said that, I find it
> confusing that we don't do that, for one reason that Tom explained and also
> because there is practically just no way to flush those dirty buffers to
> disk if the user wants so.

Which reason, except the faster shutdown, for a user to want that?

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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