Re: Proposal - Allow extensions to set a Plan Identifier

On Sun, Mar 23, 2025 at 9:43 PM Michael Paquier <michael(at)paquier(dot)xyz> wrote:

> So I've applied the patch for now, to start with
> something.
>

Thanks for committing that, I think that's a great starting point for 18!

Ideally we can also land the jumble funcs work in the other thread to allow
extensions to re-use the in-core logic for jumbling expressions found in
plan node trees.

> > FWIW, Lukas did start a Wiki [0] to open the discussion for what parts
> > of the plan should be used to compute a plan_id, and maybe we can
> > in the future compite a plan_id in core by default.
>
> Let's see where this leads.. I suspect that this is going to take
> some time, assuming that we're ever able to settle on a clear
> definition. Perhaps we will, or perhaps we will not.
>

I think there is a good chance we'll land on a reasonable planid
calculation for core (or at least a pg_stat_plans in contrib that does its
own tree walk) within the PG19 development cycle - I think plan IDs are
actually less complicated than query IDs in terms of what should be
considered unique - but maybe that's just my perspective :)

I'll be at PGConf.dev this year, would be great to do an unconference
session to discuss this further.

Thanks,
Lukas

--
Lukas Fittl