On Tue, Jun 16, 2020 at 11:49:15AM +0200, Koen De Groote wrote: > Alright, I've done that, and that seems to be a very good result: https:// > explain.depesz.com/s/xIph > > The method I ended up using: > > create or replace function still_needs_backup(shouldbebackedup bool, > backupperformed bool) > returns BOOLEAN as $$ > select $1 AND NOT $2; > $$ > language sql immutable; > > And the index is as suggested. > > It seems the amount of rows we end up with has improved. > > Thank you for your help. I wasn't aware functions could interact with indexes > in such a manner. This blog entry explains how statistics on expression/function indexes can help: https://momjian.us/main/blogs/pgblog/2017.html#February_20_2017 -- Bruce Momjian <bruce@xxxxxxxxxx> https://momjian.us EnterpriseDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee
