As it was said in the previous post we are continuing to post some tips that would help to optimize rails application.
In some cases it could greatly increase performance, but anyway it would be helpful for every RoR application.

find_by_sql method

find_by_sql method works faster then calling model accessors. So:

Person.find_by_name("Name")

Person.find_by_sql("SELECT persons.* WHERE persons.name = 'Name'")

IDs and numbers in quotes

You should never put number in quotes in your queries. It's slow.
It would be faster in this way:

WHERE id = 123 (not WHERE id= "123")

It's better to request only specific column

Let me show what I mean. This request will read all columns from database table and then choose the only needed:

Person.find_by_name("Name").phone_number

Person.find_by_sql("SELECT persons.phone_number WHERE persons.name = 'Name'")

So, here are three really simple optimizing tips that definitely would increase RoR performance.

Post was prepared using this blog.