On 26 October 2017 at 23:30, Robert Haas <robertmh...@gmail.com> wrote: > 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?
hmm, I think I was wrong about that now. I had been looking over the regression test diffs after having made tenk1 a partitioned table with a single partition containing all the rows, but it looks like I read the diff backwards. The planner actually parallelized the Append version, not the non-Append version, like I had previously thought. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
