Re: remove_useless_joins vs. bug #19560

Richard Guo <guofenglinux(at)gmail(dot)com> writes:
> On Fri, Aug 28, 2026 at 12:53 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> I take your point that the early-exit-for-trivial-jointree path now
>> fails to set these fields at all, but I'd rather handle that by
>> adding a couple more lines in that path to fill them in. Yup, it'd
>> be duplicate logic, but it seems cleaner that way.

> Fair enough. I agree that keeping all of this together at the end of
> query_planner makes it clear that these fields are not valid before
> then, and that a half-filled set during the restart loop is a hazard.
> Adding the few lines to the early-exit path sounds good to me.

Cool.

>> Well, yeah, but on that argument we could drop the entire stanza,
>> because it's just checking that join_is_removable didn't mess up.
>> Maybe we should? I've not heard that anybody ever hit those Asserts.

> I think so.

Sold. I'll make it so and push. Thanks for reviewing!

regards, tom lane