Making N+1 query detection actually useful at scale

Thu, 01 Jan 2026 12:00:00 +0000

Why N+1 queries matter

An N+1 query is one of the most common performance anti-patterns in applications powered by relational databases. It happens when code loads a collection of records, then lazily fetches an association for each one individually effectively turning what should be 1 query into N+1.

# 1 query to load users
users = User.where(team_id: team.id)

# + N queries, one per user, to load their profile
users.each { |u| puts u.profile.bio }

At large scale where N might be 100, 200, or 1,000, it’s not a great thing:

N+1-Queries on Hi, I'm Braddy

Making N+1 query detection actually useful at scale

Why N+1 queries matter