Re: Make \d tablename fast again, regression introduced by 85b7efa1cdd

"Jelte Fennema-Nio" <postgres(at)jeltef(dot)nl> writes:
> (forked from: Test timings are increasing too fast for cfbot)
> On Wed, 25 Mar 2026 at 04:15, Andres Freund <andres(at)anarazel(dot)de> wrote:
>> It seems decidedly not optimal that "\d tablename", without any patterns, ends
>> up doing a seqscan.
>> ...
>> I don't think this was always the case?

> Due to a very similar problem I faced in the past[1], I thought I had a
> good sense of where roughly the problem was. And I indeed quickly found
> it.
> Attached is a patch that addresses this issue and starts using index
> scans again for \d tablename.

I looked this over, and I think it's basically right, but don't
we need to check that *both* of the collations are deterministic?

Also the commit message had a lot of details wrong. AFAICS this
only affects the exact-match case not prefix-match, and it applies
to regexes as well as LIKE.

See attached v2.

regards, tom lane