Re: WIP: Aggregation push-down - take2

Hi,

On 7/12/22 08:49, Fujii(dot)Yuki(at)df(dot)MitsubishiElectric(dot)co(dot)jp wrote:
> Hi everyone.
>
> I rebased the following patches which were submitted in [1].
> v17-0001-Introduce-RelInfoList-structure.patch
> v17-0002-Aggregate-push-down-basic-functionality.patch
> v17-0003-Use-also-partial-paths-as-the-input-for-grouped-path.patch
>
> I checked I can apply the rebased patch to commit 2cd2569c72b8920048e35c31c9be30a6170e1410.
>
> I'm going to register the rebased patch in next commitfest.
>
I've started looking at this patch series again, but I wonder what's the
plan. The last patch version no longer applies, so I rebased it - see
the attachment. The failures were pretty minor, but there're two warnings:

pathnode.c:3174:11: warning: variable 'agg_exprs' set but not used
[-Wunused-but-set-variable]
Node *agg_exprs;
^
pathnode.c:3252:11: warning: variable 'agg_exprs' set but not used
[-Wunused-but-set-variable]
Node *agg_exprs;
^

so there seem to be some loose ends. Moreover, there are two failures in
make check, due to plan changes like this:

+ Finalize GroupAggregate
Group Key: p.i
- -> Nested Loop
- -> Partial HashAggregate
- Group Key: c1.parent
- -> Seq Scan on agg_pushdown_child1 c1
- -> Index Scan using agg_pushdown_parent_pkey on ...
- Index Cond: (i = c1.parent)
-(8 rows)
+ -> Sort
+ Sort Key: p.i
+ -> Nested Loop
+ -> Partial HashAggregate
+ Group Key: c1.parent
+ -> Seq Scan on agg_pushdown_child1 c1
+ -> Index Scan using agg_pushdown_parent_pkey on ...
+ Index Cond: (i = c1.parent)
+(10 rows)

This seems somewhat strange - maybe the plan is correct, but the extra
sort seems unnecessary.

However, maybe I'm confused/missing something? The above message says
v17 having parts 0001-0003, but there's only one patch in v18. So maybe
I failed to apply some prior patch?

regards

--
Tomas Vondra
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