On 2016/08/31 16:42, Pavel Stehule wrote: > 2016-08-31 9:00 GMT+02:00 Robert Haas <robertmhaas@gmail.com>: > >> On Wed, Aug 31, 2016 at 11:56 AM, Pavel Stehule <pavel.stehule@gmail.com> >> wrote: >>> It is pity - lot of performance issues are related to this missing >> feature. >> >> I don't think you are being very clear about what feature you are >> talking about. The feature that Jeevan has implemented is pushing >> aggregates to the remote side when postgres_fdw is in use. The >> feature you are talking about is evidently something else, but you >> haven't really said what it is. Or not in a way that I can >> understand. >> > > yes, It is not clear if FDW aggregate push down can be implemented together > with internal aggregate push down. Aggregate push down ~ try to aggregate > first when it is possible
What do you mean by "internal aggregate push down"? Partition-wise aggregation? Aggregate/group by before join (something like [1])? IIUC, what Jeevan proposes in this thread is to implement the aggregate push down API that is specific to FDWs in postgres_fdw. Any other push down work would need to use different APIs and would need to separately proposed/discussed.
