On Tue, Nov 3, 2015 at 5:04 AM, Robert Haas <
robertmhaas@gmail.com> wrote:
>
> On Sat, Oct 31, 2015 at 1:32 AM, Amit Kapila <
amit.kapila16@gmail.com> wrote:
> >
> > What is your main worry about changing the name of this map, is it
> > about more code churn or is it about that we might introduce new issues
> > or is it about that people are already accustomed to call this map as
> > visibility map?
>
> My concern is mostly that I think calling it the "visibility and
> freeze map" is excessively long and wordy.
>
> One observation that someone made previously is that there is a
> difference between "all-visible" and "index-only scan OK". An
> all-visible page that has a HOT update is no longer all-visible (it
> needs vacuuming) but an index-only scan would still be OK (because
> only the non-indexed values in the tuple have changed, and every scan
> scan can see either the old or the new tuple but not both. At
> present, the index-only scan will consult the heap page anyway,
> because all we know is that the page is not all-visible. But maybe in
> the future somebody will decide to add a bit for that. Then we'd have
> the "visibility, usable for index-only scans, and freeze map", but I
> think "_vufiosfm" will not be a good choice for a file suffix.
>
I think in that case we can call it as page info map or page state map, but
I find retaining visibility map name in this case or for future (if we want to
add another bit) as confusing. In-fact if you find "visibility and freeze map",
as excessively long, then we can change it to "page info map" or "page state
map" now as well.
