ActiveRecord seems great until it isn't--though I still think in SQL first and foremost. Common problems are (1) instantiation of many preloaded associated AR m

ActiveRecord seems great until it isn't--though I still think in SQL first and foremost. Common problems are (1) instantiation of many preloaded associated AR models that lead to memory pressure and GC time, (2) N+1 queries--yes you can preload, but there aren't easy ways of avoiding them on mutating a batch of AR models (validations and other callbacks on them don't batch).