Re: relaxing sync commit if no WAL written (was Re: unlogged tables)

On Sun, 2010-12-19 at 07:33 -0500, Robert Haas wrote:
> On Sun, Dec 19, 2010 at 7:01 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
> > On Fri, 2010-12-17 at 13:35 -0500, Robert Haas wrote:
> >
> >> I'm
> >> thinking it makes sense to commit this part first.
> >
> > This will break Hot Standby, as previously explained. Don't.
> 
> Uh, why?  Skipping the commit record altogether would do that, but
> this patch doesn't do that.

I was looking for XLogStandbyInfoActive()

It isn't there, so you're either breaking HS or missing a possible
optimisation. Having said that, it would be useful to be able to assume
that all xids appear in the log, for diagnostic purposes. 

So I now agree with the way you've coded it.

-- Simon Riggs           http://www.2ndQuadrant.com/books/PostgreSQL Development, 24x7 Support, Training and Services