In addition, for things that can't be done easily with ActiveRecord, you can write your own SQL, but then you really need to know SQL to get the performance right.
Where I work, our main product is a Rails monolith, over 10 years old at this point. The few serious performance issues we currently have are due to complicated SQL queries written back when the DB was much smaller.
Where I work, our main product is a Rails monolith, over 10 years old at this point. The few serious performance issues we currently have are due to complicated SQL queries written back when the DB was much smaller.