On 04/16/2014 06:13 PM, Linos wrote:
I thought that Postgresql would optimize out joins on columns I don't ask for when I use the view but it doesn't, this query:
It doesn't, because it would be wrong. It still has to check that the tables have a matching row (or multiple matching rows).
If you use LEFT JOINs instead, and have a unique index on all the ID columns, then the planner can do what you expected and leave out the joins.
- Heikki -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
