Re: [PATCH] Check that index can return in get_actual_variable_range()

Hi Maxime,

> Some recent changes were made to remove the explicit dependency on btree indexes in some parts of the code. One of
thesechanges was made in commit 9ef1851685b, which allows non-btree indexes to be used in get_actual_variable_range().
Afollow-up commit ee1ae8b99f9 fixes the cases where an index doesn’t have a sortopfamily as this is a prerequisite to
beused in get_actual_variable_range(). However, I found out recently that indices that have ‘amcanorder = true’ but do
notallow index-only-scans (amcanreturn returns false or is NULL) will pass all of the conditions, while they should be
rejectedsince get_actual_variable_range() uses the index-only-scan machinery in get_actual_variable_endpoint(). 
>
> Attached is a small patch that adds a check in get_actual_variable_range() to reject indices that do not allow
index-onlyscans. 

Thanks for the patch.

Can you think of any test cases we can add to the code base?

--
Best regards,
Aleksander Alekseev