On Tue, Mar 22, 2016 at 2:27 PM, Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: > For example these two queries got almost 2x as slow for some data sets: > > SELECT a FROM numeric_test UNION SELECT a FROM numeric_test_padding > SELECT a FROM text_test UNION SELECT a FROM text_test_padding > > I assume the slowdown is related to the batching (as it's only happening for > low work_mem values), so perhaps there's an internal heuristics that we > could tune?
Can you show trace_sort output for these cases? Both master, and patched? Thanks -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
