2016-08-31 8:17 GMT+02:00 Jeevan Chalke <jeevan.cha...@enterprisedb.com>:
> > > 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. > It is pity - lot of performance issues are related to this missing feature. Regards Pavel > > >> >> Regards >> >> Pavel >> >> >>> >>> >> > > Thanks > -- > Jeevan B Chalke > Principal Software Engineer, Product Development > EnterpriseDB Corporation > The Enterprise PostgreSQL Company > >
