On Tue, Aug 30, 2016 at 6:51 PM, Pavel Stehule <pavel.steh...@gmail.com> wrote:
> Hi > > 2016-08-30 15:02 GMT+02:00 Jeevan Chalke <jeevan.cha...@enterprisedb.com>: > >> Hi all, >> >> Attached is the patch which adds support to push down aggregation and >> grouping >> to the foreign server for postgres_fdw. Performing aggregation on foreign >> server results into fetching fewer rows from foreign side as compared to >> fetching all the rows and aggregating/grouping locally. Performing >> grouping on >> foreign server may use indexes if available. So pushing down aggregates/ >> grouping on foreign server performs better than doing that locally. >> (Attached >> EXPLAIN output for few simple grouping queries, with and without push >> down). >> > > is it work without FDW too?. It can be pretty interesting too. > No. Aggrgate push down is supported through the GetForeignUpperPaths() hook added for postgres_fdw. Thus it works only with postgres_fdw. Do you mean whether this works with any extensions via implementing create_upper_paths_hook() function? The answer is No. This patch does not touch this hook. > > Regards > > Pavel > > >> >> > Thanks -- Jeevan B Chalke Principal Software Engineer, Product Development EnterpriseDB Corporation The Enterprise PostgreSQL Company
