This is because join negatively impact the scalability of a DB: - When huge amount of traffic hits your DB, out of the most commonly run-out resources - CPU, M

This is because join negatively impact the scalability of a DB: - When huge amount of traffic hits your DB, out of the most commonly run-out resources - CPU, Memory, and IO - CPU is usually the one that runs out first. And Join uses quite a bit of CPU. - When you have a lot of data and have to partition it, you will feel so lucky if you don't have to deal with distributed joins.