Ruby On Rails is slow…?

Question

I\'m writing a web application to monitor a furniture factory production flow. It has thousand of data to handle. So far, I run RoR on Mongrel + MySQL and it\'s really really sl

Answer 1

You might profile the code first before doing anything, though, queries inside for loops are a very common cause for performance problems and at first sight this seems your problem. You might anyway find a practical profiler here:

As already said on the other answers, if both models are related you should eager load the associations, which implies instructing Active Record to perform join queries:

#left outer join
ofkbs=Ofkb.includes(:operation).where(name: "banana")

If you do not need the ofkbs but only the operations, you could perform an inner join

#inner join (discards the Ofkbs that do not have any operation)
operations=Operation.joins(:ofkb).where(ofkb:{name:"banana"})

This solution only preforms one query, and allows you to afterwards iterate through the data that will have already been collected from the DB:

operations=ofkbs.map{|of| of.operations}.flatten

operations.each do |o|
  do_whatever_you_want_with_operation(o)
end

If the queries are very complicated you should use arel instead.