Re: Asymmetric partition-wise JOIN

On Sun, Oct 15, 2023 at 8:40 AM Andrei Lepikhov
<a(dot)lepikhov(at)postgrespro(dot)ru> wrote:
> Thanks for such detailed feedback!
> The rationale for this patch was to give the optimizer additional ways
> to push down more joins into foreign servers. And, because of
> asynchronous append, the benefit of that optimization was obvious.
> Unfortunately, we hadn't found other applications for this feature,
> which was why this patch was postponed in the core.
> You have brought new ideas about applying this idea locally. Moreover,
> the main issue of the patch was massive memory consumption in the case
> of many joins and partitions - because of reparameterization. But now,
> postponing the reparameterization proposed in the thread [1] resolves
> that problem and gives some insights into the reparameterization
> technique of some fields, like lateral references.
> Hence, I think we can restart this work.
> The first thing here (after rebase, of course) is to figure out and
> implement in the cost model cases of effectiveness when asymmetric join
> would give significant performance.

Great! I'm looking forward to the revised patch.

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Regards,
Alexander Korotkov