Re: Need help with clarification on stored procedure support in PostGreSQL database

On Tue, Mar 9, 2021 at 3:21 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> "David G. Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> writes:
> > The omission of the "OUT" parameter mode seems intentional since at
> present
> > our procedures do not support OUT mode parameters.
>
> Um, I just created one. I think this *used* to be true, and this bit of
> the docs didn't get fixed. If I back-patch this, I'll have to research
> when it changed.
>

Five months ago it seems.

https://github.com/postgres/postgres/commit/2453ea142233ae57af452019c3b9a443dad1cdd0

The patch and email thread for that commit make me pause, though I cannot
put into words why.

>
> > Instead of "The difference" or "One difference" I would suggest:
> "However,
> > a procedure does not return a value, so there is no return type
> > declaration; though a procedure can declare INOUT (but not plain OUT)
> > parameters."
>
> Not sure if that's an improvement.
>

The "however" part is probably a wash; I just dislike seeing a count
started and not having an ending and thus being left in a state of "what
didn't they include that's important".

The part about commenting about OUT/INOUT parameters still working even
though there is no return provide complete coverage of the
differences/similarities between functions and procedures with respect to
passing back data to the caller.

>
> > Relocating the links to the description instead of usage is good. The
> > additional procedure link after the examples seems redundant,
> particularly
> > as the linked to location doesn't actually have more examples.
>
> I was modeling that on the existing pattern in create_function.sgml,
> which has similar verbiage in the EXAMPLES section. But I suppose
> we could drop that if we have a link in the description section.
>
>
Yeah, it was an existing deficiency, but being a bit more invasive seems
warranted, and as you say it is be located partly because it is much higher
level content being pointed to (hence description, not usage/examples).

David J.