I have a "items" table with 1 million rows and a "users" table with 20,000 rows. When I select from the "items" table I do a join on the "users" table (items.user_id = user.id), so that I can grab the "username" from the users table.

I'm considering adding a username column to the items table and removing the join. Can I expect a decent performance increase from this? It's already quite fast, but it would be nice to decrease my load (which is pretty high).

The downside is that if the user changes their username, items will still reflect their old username, but this is okay with me if I can expect a decent performance increase.

I'm asking stackoverflow because benchmarks aren't telling me too much. Both queries finish very quickly. Regardless, I'm wondering if removing the join would lighten load on the database to any significant degree.