Re: COPY FREEZE and setting PD_ALL_VISIBLE/visibility map bits

Hi,

On 2019-04-05 00:06:04 -0300, Alvaro Herrera wrote:
> On 2019-Apr-04, Andres Freund wrote:
> 
> > On 2019-04-04 12:23:08 -0700, Andres Freund wrote:
> > > Also, how is this code even close to correct?
> > > CheckAndSetPageAllVisible() modifies the buffer in a crucial way, and
> > > there's no WAL logging? Without even a comment arguing why that's OK (I
> > > don't think it is)?
> > 
> > Peter Geoghegan just reminded me over IM that there's actually logging
> > inside log_heap_visible(), called from visibilitymap_set(). Still lacks
> > a critical section though.
> 
> Hmm, isn't there already a critical section in visibilitymap_set itself?

There is, but the proposed code sets all visible on the page, and marks
the buffer dirty, before calling visibilitymap_set.

Greetings,

Andres Freund