Re: Improve docs for n_distinct_inherited

On Wed, May 7, 2025 at 11:41 PM David Rowley <dgrowleyml@gmail.com> wrote:

> On Thu, 8 May 2025 at 15:23, David G. Johnston
> <david.g.johnston@gmail.com> wrote:
> > Not liking the proposal, not sure it is even correct.  Somehow "children
> of inheritance parent tables" are omitted.
>
> I don't see the quoted text anywhere in this area, so I'm not sure I
> follow what you mean with the omission.
>

Omitted from your v1 patch.

The two options for sample
> sets are 1) stainherits==true and 2) stainherits==false. With
> inheritance parent tables, ANALYZE gathers both sets and records both
> sets in pg_statistic.


I was missing this key piece of knowledge which invalidated my entire
attempt.

Here's an attempt at shortening this now that I understand the mechanics
better.

      Separate options exist because an inheritance parent table has two
      different sets of statistics: one considering only itself and one
which
      also includes its children (<literal>n_distinct_inherited</literal>).
      Partitioned tables, which only have rows in the children, likewise
uses
      the inherited option while everyone else uses
<literal>n_distinct</literal>.

David J.