On Mon, Aug 27, 2018 at 6:05 PM, Jonathan S. Katz <jk...@postgresql.org> wrote: > On behalf of the RMT, I just want to make sure this keeps moving along. > It sounds like the next step is for Robert to verify that [3] is the > expected > behavior and then David can decide what to do from there.
Yes, that's the expected behavior. If we didn't regenerate the paths there, we'd end up with Result -> Append -> [various paths that produce a tlist which needs to be adjusted later by the result node] Instead of: Append -> [various paths that produce an adjusted tlist] Paths of the former kind have already been generated; we regenerate paths here to get the latter kind as well, which end up displacing the old ones on cost. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
