Re: Extensibility of the PostgreSQL wire protocol

On Thu, 11 Feb 2021 at 09:28, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:

> On Wed, Feb 10, 2021 at 2:04 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > That is a spot-on definition of where I do NOT want to end up. Hooks
> > everywhere and enormous extensions that break anytime we change anything
> > in the core. It's not really clear that anybody is going to find that
> > more maintainable than a straight fork, except to the extent that it
> > enables the erstwhile forkers to shove some of their work onto the PG
> > community.
>
> +1.
>
> Making the lexer and parser extensible seems desirable to me. It would
> be beneficial not only for companies like EDB and Amazon that might
> want to extend the grammar in various ways, but also for extension
> authors. However, it's vastly harder than Jan's proposal to make the
> wire protocol pluggable. The wire protocol is pretty well-isolated
> from the rest of the system. As long as you can get queries out of the
> packets the client sends and package up the results to send back, it's
> all good.

I would have to disagree that the wire protocol is well-isolated. Sending
and receiving are not in a single file
The codes are not even named constants so trying to find a specific one is
difficult.

Anything that would clean this up would be a benefit

That being said, I'm not in favor of transferring maintenance work to
> the community for this set of hooks any more than I am for something
> on the parsing side. In general, I'm in favor of as much extensibility
> as we can reasonably create, but with a complicated proposal like this
> one, the community should expect to be able to get something out of
> it. And so far what I hear Jan saying is that these hooks could in
> theory be used for things other than Amazon's proprietary efforts and
> those things could in theory bring benefits to the community, but
> there are no actual plans to do anything with this that would benefit
> anyone other than Amazon. Which seems to bring us right back to
> expecting the community to maintain things for the benefit of
> third-party forks.
>

if this proposal brought us the ability stream results that would be a huge
plus!

Dave Cramer
www.postgres.rocks

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