There are some really glaring issues in this article. For example, the author suggests that each -> update is worse than update_all, and while the performance m

There are some really glaring issues in this article. For example, the author suggests that each -> update is worse than update_all, and while the performance may be better it's comparing apples to oranges! update_all, in ActiveRecord, bypasses business logic, bypasses updating the updated_at, bypasses validation and more. It's not the same thing at all. There is no difference between where.first and find_by, that is just a bikeshed. Not every map(column) can be turned into pluck(column) if there are business logic wrappers around that column.