2026년 9월 29일 · 16 min read · ruby / rails
What Does Active Record Build on Every Request? Measured the Same Way as Sequelize and GORM
The last post concluded that Ruby is not slow and that most of a Rails request is Active Record. This one compares what Active Record does per request with Sequelize and GORM, by reading the source and measuring. Most of the cost comes from a has_and_belongs_to_many preload that turns every join row into a full record, and there is a way to cut it sharply while keeping the same SQL.