Partition pruning / agg push down for star schema in pg v11

Hello,

Working on Oracle migration POCs, I'm very interested in v11 and declarative
partitioning optimizations.

I have a typical star schema, having dimension tables "product", "calendar"
and "country" and a fact table "sales".
This fact table is partitionned by time (range by month) and country (list).

Will query like:

select product.name, calendar.month, sum(sales.net_price)
from sales
inner join product on (product.id = sales.cust_id)
inner join country on (country.id = sales.country_id)
inner join calendar on (calendar.id = sales.calendar_id)
where
country.name = 'HERE'
and calendar.year = '2017'
group by product.name,calendar.month

be able to identify needed partitions ?

nb: the query has predicates on dimension tables not on columns used for
fact table partitioning:
- country.name vs sales.country_id,
- calendar.year vs sales.calendar_id.

Second question: will some aggregation be pushed to the fact table ?

Something like
select product.name,calendar.month,agg.sum_net
from
(select product_id,calendar_id,sum(net_price) as sum_net
from sales
inner join country on (country.id = sales.country_id)
inner join calendar on (calendar.id = sales.calendar_id)
where
country.name = 'HERE'
and calendar.year = '2017') agg
inner join product on (product.id = agg.cust_id)
inner join calendar on (calendar.id = agg.calendar_id)
group by product.name,calendar.month

Thanks in advance (commitfest or patches references are welcome)

Regards
PAscal

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