On Mon, Oct 24, 2016 at 2:07 PM, Lars Aksel Opsahl <lars.ops...@nibio.no> wrote: > Hi > > Yes this makes both the update and both selects much faster. We are now down > to 3000 ms. for select, but then I get a problem with another SQL where I > only use epoch in the query. > > SELECT count(o.*) FROM met_vaer_wisline.nora_bc25_observation o WHERE > o.epoch = 1288440000; > count > ------- > 97831 > (1 row) > Time: 92763.389 ms > > To get the SQL above work fast it seems like we also need a single index on > the epoch column, this means two indexes on the same column and that eats > memory when we have more than 4 billion rows. > > Is it any way to avoid to two indexes on the epoch column ?
You could try reversing the order. Basically whatever comes first in a two column index is easier / possible for postgres to use like a single column index. If not. then you're probably stuck with two indexes. -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
