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ActiveRecord provides powerful query interface, but naive usage causes N+1 queries. includes eager loads associations in 2-3 queries. joins performs SQL JOINs for filtering. preload always uses separate queries; eager_load forces LEFT OUTER JOIN. I us

N+1 queries are the most common Rails performance problem—loading associations in loops causes exponential database queries. The Bullet gem detects N+1s in development and suggests fixes. It monitors queries and alerts when you should use includes, pr