Re: BUG #14404: High row estimates when query uses master inherited tables

I wrote:
> Ah.  So this must be something to do with the foreign-key-driven rowcoun=
t
> estimates we added in 9.6.  Will look into it, thanks for the report!

I think the answer is that we failed to consider inheritance cases at all
while developing the aforementioned logic.  For the moment, I've
band-aided this by disabling the FK estimation logic when either relation
is an inheritance parent.  If you need a patch immediately, see

https://git.postgresql.org/gitweb/?p=3Dpostgresql.git;a=3Dcommitdiff;h=3D2=
3c6c437f98c996092c0adfad6152d9cc699c8b0

            regards, tom lane