Re: extended stats on partitioned tables

On Thu, Nov 04, 2021 at 12:44:45AM +0100, Tomas Vondra wrote:
> >> And I'm not sure we do the right thing after removing children, for example
> >> (that should drop the inheritance stats, I guess).

> > Do you mean for inheritance only ? Or partitions too ?
> > I think for partitions, the stats should stay.
> > And for inheritence, they can stay, for consistency with partitions, and since
> > it does no harm.
>
> I think the behavior should be the same as for data in pg_statistic,
> i.e. if we keep/remove those, we should do the same thing for extended
> statistics.

That works for column stats the way I proposed for extended stats: child stats
are never removed, neither when the only child is dropped, nor when re-running
analyze (that part is actually a bit odd).

Rebased, fixing an intermediate compile error, and typos in the commit message.

--
Justin