Make ActiveRecord Faster

ActiveRecord is a wrapper around your data. By definition that should take memory, and oh indeed it does. It turns out the overhead is quite significant, in both the number of objects and in raw memory.

To see the overhead, let’s create a database table with 10 string columns and fill it with 10,000 rows, each row containing 10 strings of 100 chars.

class​ LargeTables < ActiveRecord::Migration
def​ up
create_table :things ​do​ |t|
10.times ​do​ |i|
t.string ​"col​#{i}​"
execute ​<<-END
insert into things(col0, col1, col2, col3, col4,
col5, col6, col7, col8, col9) (
rpad('x', 100, 'x'), rpad('x', 100, 'x'), rpad('x', ...

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