On Wed, 20 Jun 2018 at 19:08, David Rowley <david.rowley@2ndquadrant.com> wrote: > I'll submit it again when there more consensus that we want this. Waking up this old thread again. If you don't have a copy, the entire thread is in [1]. The remaining item that seemed to cause this patch to be rejected was raised in [2]. The summary of that was that it might not be a good idea to allow parallel aggregation of string_agg() and array_agg() as there might be some people who rely on the current ordering they get without having an ORDER BY clause in the aggregate function call. Tom mentioned in [3] that users might not want to add an ORDER BY to their aggregate function because the performance of it is terrible. That was true up until 1349d2790 [4], where I changed how ORDER BY / DISTINCT aggregation worked to allow the planner to provide pre-sorted input rather than always having nodeAgg.c do the sorting. I think this removes quite a lot of the argument against the patch, but not all of it. So here goes testing the water on seeing if any opinions have changed over the past few years? A rebased patch is attached. David [1] https://www.postgresql.org/message-id/flat/CAKJS1f98yPkRMsE0JnDh72%3DAQEUuE3atiCJtPVCtjhFwzCRJHQ%40mail.gmail.com#8bbce15b9279d2da2da99071f732a99d [2] https://www.postgresql.org/message-id/6538.1522096067@sss.pgh.pa.us [3] https://www.postgresql.org/message-id/18594.1522099194@sss.pgh.pa.us [4] https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=1349d2790bf48a4de072931c722f39337e72055e
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