Re: Incremental View Maintenance, take 2

On Tue, 20 Aug 2024 at 02:14, Kirill Reshke <reshkekirill(at)gmail(dot)com> wrote:
>
>
> == Major suggestions.
>
> 1) At first glance, working with this IVM/IMMV infrastructure feels
> really unintuitive about what servers actually do for query execution.
> I do think It will be much better for user experience to add more
> EXPLAIN about IVM work done inside IVM triggers. This way it is much
> clearer which part is working slow, so which index should be created,
> etc.
>
> 2) The kernel code for IVM lacks possibility to be extended for
> further IVM optimizations. The one example is foreign key optimization
> described here[1]. I'm not saying we should implement this within this
> patchset, but we surely should pave the way for this. I don't have any
> good suggestions for how to do this though.
>
> 3) I don't really think SQL design is good. CREATE [INCREMENTAL] M.V.
> is too ad-hoc. I would prefer CREATE M.V. with (maintain_incr=true).
> (reloption name is just an example).
> This way we can change regular M.V. to IVM and vice versa via ALTER
> M.V. SET *reloptions* - a type of syntax that is already present in
> PostgreSQL core.
>

One little follow-up here. Why do we do prepstate visibility the way
it is done? Can we instead export the snapshot in BEFORE trigger, save
it somewhere and use it after?

--
Best regards,
Kirill Reshke