On Wed, Mar 31, 2021 at 1:24 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > I agree that we have some existing behavior that's related to this, but > it's still messy, and I couldn't find any evidence that suggested that the > runtime lookup costs anything. Typical subplans are going to deliver > long runs of tuples from the same target relation, so as long as we > maintain a one-element cache of the last lookup result, it's only about > one comparison per tuple most of the time.
OK, that's pretty fair. -- Robert Haas EDB: http://www.enterprisedb.com
