On Sun, 28 Jul 2019 at 11:15, Tomas Vondra <tomas.vondra@2ndquadrant.com> wrote:
>
> Attached is a patch fixing the error by not building extended stats for
> the inh=true case (as already proposed in this thread). That's about the
> simplest way to resolve this issue for v12. It should add a simple
> regression test too, I guess.
>
Seems like a reasonable thing to do for 10, 11 and possibly also 12
(actually, as you noted, I think it's the only thing that can be done
for 10 and 11).
> To fix this properly we need to add a flag similar to stainherit
> somewhere. And I've started working on that, thinking that maybe we
> could do that even for v12 - it'd be yet another catversion bump, but
> there's already been one since beta2 so maybe it would be OK.
>
Yeah, I think that makes sense, if it's not too hard. Since v12 is
where the stats definition is split out from the stats data, this
might work out quite neatly, since the inh flag would apply only to
the stats data.
> But it's actually a bit more complicated than just adding a column to
> the catalog, for two reasons:
>
> 1) The optimizer part has to be tweaked to pick the right object, with
> the flag set to either true/false. Not trivial, but doable.
>
Isn't it just a matter of passing the inh flag to
get_relation_statistics() from get_relation_info(), so then the
optimiser would get the right kind of stats data, depending on whether
or not inheritance was requested in the query.
Regards,
Dean