Re: Custom/Foreign-Join-APIs (Re: [v9.5] Custom Plan API)

On Sun, May 10, 2015 at 10:37 PM, Andres Freund <andres@anarazel.de> wrote:
> On 2015-05-10 21:53:45 -0400, Robert Haas wrote:
>> Please name EVEN ONE instance in which core development has been
>> prevented for fear of changing a function API.
>
> Even *moving* function declarations to a different file has been laudly
> and repeatedly complained about...

Moving declarations is a lot more likely to break compiles than adding
declarations.  But even the 9.3 header file reorganizations, which
broke enough compiles to be annoying, were only annoying, not a
serious problem for anyone.  I doubted whether that stuff was worth
changing, but that's just because I don't really get excited about
partial recompiles.

> And there's definitely some things
> around that pretty much only still exist because changing them would
> break too much stuff.

Such as what?

> But.
>
> I don't think that's a reason to not expose more functions
> externally. Because the usual consequence of not exposing them is that
> either ugly workarounds will be found, or code will just copy pasted
> around. That's not in any way better, and much likely to be worse.

Yes.

> I'm not saying that we shouldn't use judgement, but I do think that the
> current approach ridicules our vaunted extensibility in many cases.

Double yes.

-- 
Robert Haas
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