On 2014-12-03 10:51:19 -0500, Robert Haas wrote: > On Wed, Dec 3, 2014 at 4:29 AM, David Rowley <dgrowle...@gmail.com> wrote: > > *** Method 1: Removing Inner Joins at planning time: > > > > *** Method 2: Marking scans as possibly skippable during planning, and > > skipping joins at execution (Andres' method) > > > > *** Method 3: Marking scans as possibly skippable during planning and > > removing redundant join nodes at executor startup (Simon's method) > [....] > > a. can we invoke the planner during executor init? > > I'm pretty sure that we can't safely invoke the planner during > executor startup, and that doing surgery on the plan tree (option #3) > is unsafe also. I'm pretty clear why the latter is unsafe: it might > be a copy of a data structure that's going to be reused.
We already have a transformation between the plan and execution tree. I'm right now not seing why transforming the trees in ExecInitNode() et. al. would be unsafe - it looks fairly simple to switch between different execution plans there. Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
