Re: Assertion failure with LEFT JOINs among >500 relations

David Rowley <dgrowleyml(at)gmail(dot)com> writes:
> On Mon, 19 Oct 2020 at 12:10, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> TBH, I see no need to do anything in the back branches. This is not
>> an issue for production usage.

> I understand the Assert failure is pretty harmless, so non-assert
> builds shouldn't suffer too greatly. I just assumed that any large
> stakeholders invested in upgrading to a newer version of PostgreSQL
> may like to run various tests with their application against an assert
> enabled version of PostgreSQL perhaps to gain some confidence in the
> upgrade. A failing assert is unlikely to inspire additional
> confidence.

If any existing outside regression tests hit such corner cases, then
(a) we'd have heard about it, and (b) likely they'd fail in the older
branch as well. So I don't buy the argument that this will dissuade
somebody from upgrading.

I do, on the other hand, buy the idea that if anyone is indeed working
in this realm, they might be annoyed by a behavior change in a stable
branch. So it cuts both ways. On balance I don't think we should
touch this in the back branches.

regards, tom lane