Re: making EXPLAIN extensible

On 4/3/2025 16:14, Robert Haas wrote:
> On Tue, Mar 4, 2025 at 10:12 AM Andrei Lepikhov <lepihov(at)gmail(dot)com> wrote:
>> Also, I think this feature is quite close to the discussion on the
>> possibility of adding an extensible list field into Query, PlanState,
>> Plan, etc. nodes to let extensions gather and transfer some additional
>> data starting with the first 'analyze' hook up to the end of execution.
>> For example, in solving user issues, I frequently need to know
>> predictions on the number of groups in Memoize, IncrementalSort and some
>> other nodes. Such extensibility could allow an extension to gather such
>> internal data during the planning stage and show it in the explain
>> without any changes in the core!
>
> If you're saying there's a -hackers discussion on this, could you
> provide a link? I haven't seen it.
>
I wouldn't say there is a thread in the mailing list. I mentioned this
direction of extensibility multiple times (for example, [1,2]) with no
reaction. However, letting extensions show data in explan gives this
idea additional impulse.

[1]
https://www.postgresql.org/message-id/30113d59-8678-49ca-a8fb-bbceacf7efb0%40gmail.com
[2]
https://www.postgresql.org/message-id/CA%2BTgmoYXgBVCnFhrW3X1NxpdjWtJCYRKP38PQ-AdR-RJziTBUQ%40mail.gmail.com

--
regards, Andrei Lepikhov