On Sun, Jul 21, 2019 at 5:55 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > The FROM case could be improved perhaps, if somebody wanted to put > time into it. You'd still need to be prepared to build a tuplestore, > in case of rescan or backwards fetch; but in principle you could return > rows immediately while stashing them aside in a tuplestore.
But you could skip it if you could prove that no rescans or backward fetches are possible for a particular node, something that we also want for Gather, as discussed not long ago. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
