Set PostgreSQL "random_page_cost" to 2 instead of 4
When digging into queries for https://gitlab.com/gitlab-org/gitlab-ce/issues/30472 our DB consultant and I ran into the issue where an index was not being used, despite that it should be used. The DB consultant found out our random_page_cost
is set to 4, and that changing it to 2 resulted in:
- PostgreSQL using the index
- The query becoming about 4x faster (though we went from 16ms to 4ms, so not all that much)
We should investigate changing this value and monitor the impact.