Re: WIP: Upper planner pathification

On Tue, Mar 1, 2016 at 3:11 PM, Teodor Sigaev <teodor(at)sigaev(dot)ru> wrote:

> The basic point of this patch is to apply the generate-and-compare-Paths
>> paradigm to the planning steps after query_planner(), which only covers
>>
> ...
> > The present patch addresses this problem by inventing Path nodes to
> > represent every post-scan/join step
>
> I'm really glad to see that. Separating path nodes for later steps opens a
> new ways to optimize queries. For first glance, consider
> select * from a left outer join b on a.i = b.i limit 1;
> Limit node could be pushed down to scan over 'a' table if b.i is unique.
>

This patch opens a lot of possibilities to our ongoing project on indexing
subselects, which we plan to use for jsonb. Having it in 9.6 will
certainly facilitate this. So, I'm +1 for this patch, even if we have to
postpone 9.6 a bit. Hope, Robert, Teodor and other reviewers could help Tom
with this patch.

>
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> Teodor Sigaev E-mail: teodor(at)sigaev(dot)ru
> WWW:
> http://www.sigaev.ru/
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