2011/10/10 Shigeru Hanada <shigeru.han...@gmail.com>: > (2011/10/08 1:06), Kohei KaiGai wrote: >> What is the reason why the foreign join is not pushed down? >> Maybe, injected Sort plan prevent the planner to consider both side of >> relations being foreign scan owned by same server? I'm still >> investigating the reason. > > Thanks for your testing. > > I'm not sure, but I think that Sort plan node would not be the reason > because it's an element of merge join. Maybe some wrong points would be > in my join method consideration. > > In my assumption, ft1 and ft2 should be joined first (because such join > has very low costs) and then that result and lt3 should be joined with > one of local join methods, such as merge join and hash join.
This might be out of left field, but wouldn't it make more sense to get postgresql_fdw committed first, and then add the join push-down functionality afterwards? I mean, otherwise, we're going to be left with a situation where we have join pushdown in core, but the only FDW that can actually make use of it elsewhere. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
