advanced_eager_loading

📥 Advanced Eager Loading Strategies

Use preload, eager_load, and includes in combination with where on associations to craft the optimal query plan. Inspect EXPLAIN ANALYZE for each variation.

# Eager load users with only published posts and their recent comments
users = User
  .includes(posts: :comments)
  .where(posts: { status: 'published' })
  .references(:posts)
  .where(comments: { created_at: 1.week.ago.. })

puts User.connection.execute("EXPLAIN ANALYZE #{users.to_sql}")