On Wed, May 25, 2011 at 10:35 AM, Hitoshi Harada <umi.tan...@gmail.com> wrote: > 2011/5/25 Hitoshi Harada <umi.tan...@gmail.com>: >> So I'm still >> thinking which of pulling up and parameterized scan is better. > > After more investigation I came up with third idea, pushing down > RangeTblEntry to aggregate subquery. This sounds like a crazy idea, > but it seems to me like it is slightly easier than pulling up > agg-subquery. The main point is that when you want to pull up, you > must care if the final output would be correct with other join > relations than the aggregate-related one. In contrast, when pushing > down the target relation to agg-subquery it is simple to ensure the > result. > > I'm looking around pull_up_subqueries() in subquery_planner() to add > the pushing down logic. It could be possible to do it around > make_one_rel() but I bet query structure changes are doable against > Query, not PlannerInfo.
How do you decide whether or not to push down? -- 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
