Re: optimize lookups in snapshot [sub]xip arrays

Nathan Bossart <nathandbossart(at)gmail(dot)com> writes:
> On Tue, Aug 09, 2022 at 09:40:15AM +0530, Bharath Rupireddy wrote:
>> Isn't it a good idea to capture the above two points as comments in
>> port/pg_lfind.h just to not lose track of it? I know these are present
>> in the hackers thread, but having them in the form of comments helps
>> developers who attempt to change or use the new function.

> Hm. My first impression is that this is exactly the sort of information
> that is better captured on the lists. I'm not sure that the lack of such
> commentary really poses any threat for future changes, which would need to
> be judged on their own merit, anyway.

It's clearly unproductive (not to say impossible) to enumerate every
possible alternative design and say why you didn't choose it. If
there's some particular "obvious" choice that you feel a need to
refute, then sure write a comment about that. Notably, if we used
to do X and now do Y because X was found to be broken, then it's good
to have a comment trail discouraging future hackers from reinventing
X. But that doesn't lead to needing comments about an unrelated
option Z.

regards, tom lane