Re: Memory consumed by child SpecialJoinInfo in partitionwise join planning

On Wed, Sep 27, 2023 at 8:07 PM Ashutosh Bapat
<ashutosh.bapat.oss@gmail.com> wrote:
> On Wed, Sep 27, 2023 at 2:30 PM Amit Langote <amitlangote09@gmail.com> wrote:
> > Just out of curiosity, is their not being present in join_info_list
> > problematic in some manner, such as missed optimization opportunities
> > for child joins?  I noticed there is a loop over join_info_list in
> > add_paths_to_join_rel(), which does get called for child joinrels.  I
> > know this a bit off-topic for the thread, but thought to ask in case
> > you've already thought about it.
>
> The function has a comment and code to take care of this at the very beginning
> /*
> * PlannerInfo doesn't contain the SpecialJoinInfos created for joins
> * between child relations, even if there is a SpecialJoinInfo node for
> * the join between the topmost parents. So, while calculating Relids set
> * representing the restriction, consider relids of topmost parent of
> * partitions.
> */
> if (joinrel->reloptkind == RELOPT_OTHER_JOINREL)
> joinrelids = joinrel->top_parent_relids;
> else
> joinrelids = joinrel->relids;

Ah, that's accounted for.  Thanks.


--
Thanks, Amit Langote
EDB: http://www.enterprisedb.com