Re: Super PathKeys (Allowing sort order through precision loss functions)

On 1 November 2018 at 05:40, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> This kinda reminds me of commit
> 8f9fe6edce358f7904e0db119416b4d1080a83aa. We needed a way to provide
> the planner with knowledge about the behavior of specific functions.
> In that case, the specific need was to be able to tell the planner
> that a certain function call could be omitted or strength-reduced, and
> we did that by having the planner call a function that encoded the
> necessary knowledge. Here, we want to evaluate a function call and
> see whether it is order preserving, which could depend on a whole
> bunch of stuff that isn't easily parameterized by catalog entries, but
> could be figured out by a C function written for that purpose. I'm
> not really sure how that would work in this case, or whether it's a
> good idea, but I thought I'd mention it just in case it's helpful.

Agreed. That's a good idea. Thanks.

--
David Rowley http://www.2ndQuadrant.com/
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