Re: Add visibility map information to pg_freespace.

Hello,

> >  - How about pageinspect?
> >
> >   I proposed a simple representation format as a basis for
> >   discussion. Nevertheless, the VM pages has no more structure
> >   than a simple bit string. Given the VM info in pg_freespacemap,
> >   I've come in doubt of the necessity of vm_page_contnets() for
> >   the reason besides the orthogonality in the this extension's
> >   interface (which paid no attention before:-).
> 
> I don't think that will be needed, now I understand.

Ok, I'll drop it from the list.

> >  - How about pgstattuple?
> >
> >   It could even be said to be meaningful to add the number of
> >   not-all-visible pages or the ratio of it in the total pages..
..
> >    | free_percent                 | 37.88
> >    + not_all_visible_page_percent | 23.54
> >
> > # This column name looks too long, though.
> >
> 
> Yes, please.
> 
> But name should be all_visible_percent.
> Anybody that wants not_all_visible_percent can do the math.

You're quite right, plus, negative terms are a bit confusing.

I'll come again with the first implementation of it. And as for
pg_freespacemap, I'll keep the current direction - adding column
to present output records format of pg_freespace(). And
documentation, if possible.

regards,

-- 
Kyotaro Horiguchi
NTT Open Source Software Center