Re: hyrax vs. RelationBuildPartitionDesc

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Thu, Jun 6, 2019 at 2:48 AM Amit Langote <amitlangote09(at)gmail(dot)com> wrote:
>> Attached is a patch that applies on top of Robert's pdoldcxt-v1.patch,
>> which seems to fix this issue for me.

> Yeah, that looks right. I think my patch was full of fuzzy thinking
> and inadequate testing; thanks for checking it over and coming up with
> the right solution.

> Anyone else want to look/comment?

I think the existing code is horribly ugly and this is even worse.
It adds cycles to RelationDecrementReferenceCount which is a hotspot
that has no business dealing with this; the invariants are unclear;
and there's no strong reason to think there aren't still cases where
we accumulate lots of copies of old partition descriptors during a
sequence of operations. Basically you're just doubling down on a
wrong design.

As I said upthread, my current inclination is to do nothing in this
area for v12 and then try to replace the whole thing with proper
reference counting in v13. I think the cases where we have a major
leak are corner-case-ish enough that we can leave it as-is for one
release.

regards, tom lane