Re: Early WIP/PoC for inlining CTEs

I wrote:
> Andrew Gierth <andrew@tao11.riddles.org.uk> writes:
>> So what I think we need to do here is to forbid inlining if (a) the
>> refcount is greater than 1 and (b) the CTE in question contains,
>> recursively anywhere inside its rtable or the rtables of any of its
>> nested CTEs, a "self_reference" RTE.

> That's kind of "ugh" too: it sounds expensive, and doing it in a way
> that doesn't produce false positives would be even more complicated.

After further investigation, I concluded that that wasn't that awful,
so done that way.

I'm still not entirely convinced about the behavior for nested WITHs
with different materialization specifications, but that seems like
a separate topic.

            regards, tom lane