On Mon, Sep 09, 2019 at 02:00:01PM +0530, yash mehta wrote: > We have a query that takes 1min to execute in postgres 10.6 and the same > executes in 4 sec in Oracle database. The query is doing 'select distinct'. > If I add a 'group by' clause, performance in postgres improves > significantly and fetches results in 2 sec (better than oracle). But > unfortunately, we cannot modify the query. Could you please suggest a way > to improve performance in Postgres without modifying the query. Not sure it helps, but I remember this: https://www.postgresql.org/message-id/CAKJS1f9q0j3BgMUsDbtf9%3DecfVLnqvkYB44MXj0gpVuamcN8Xw%40mail.gmail.com