On Wed, Oct 25, 2017 at 11:59 PM, David Rowley <david.row...@2ndquadrant.com> wrote: > As of today, because we include this needless [Merge]Append node, we > cannot parallelise scans below the Append.
Without disputing your general notion that singe-child Append or MergeAppend nodes are a pointless waste, how does a such a needless node prevent parallelizing scans beneath it? > Invent a ProxyPath concept that allows us to add Paths belonging to > one relation to another relation. The ProxyPaths can have > translation_vars to translate targetlists to reference the correct > Vars. These ProxyPaths could exist up as far as createplan, where we > could perform the translation and build the ProxyPath's subnode > instead. This idea sounds like it might have some legs, although I'm not sure "proxy" is really the right terminology. Like both you and Ashutosh, I suspect that there might be some other applications for this. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers