On Wed, Nov 8, 2017 at 4:34 PM, Robert Haas <robertmh...@gmail.com> wrote: > On Tue, Nov 7, 2017 at 9:41 PM, Amit Kapila <amit.kapil...@gmail.com> wrote: >> This is required to prohibit generating gather path for top rel in >> case of inheritence (Append node) at this place (we want to generate >> it later when scan/join target is available). > > OK, but why don't we want to generate it later when there isn't > inheritance involved? >
We do want to generate it later when there isn't inheritance involved, but only if there is a single rel involved (simple_rel_array_size <=2). The rule is something like this, we will generate the gather paths at this stage only if there are more than two rels involved and there isn't inheritance involved. -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
