CODEWITHSUNDEEP
ruby-on-railsrubyclasscaching
RubyRedGrapefruit
RubyRedGrapefruit

Reputation: 12224

Class instantiation taking forever because of poor design

I have a class which reads the contents of three different files into class variables upon instantiation, like so:

class Catalog

  class << self

    def change_file_name
      standard = Standard.where(klass_name: self.to_s).first
      month = Date::ABBR_MONTHNAMES[standard.version_date.month]
      year = standard.version_date.year
      "#{Rails.root.to_s}/#{month}_#{year}_changed_products.csv"
    end

    def get_changes
      changes = {}
      begin
        IO.foreach(change_file_name) do |line|
          row = CSV.parse_line(line.encode!('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: '').strip, { quote_char: '"' })
          version = row.pop
          changes[version] ||= {}
          changes[version][row[1]] =  row[3]
        end
      rescue => bang
        raise "Error opening #{change_file_name}: #{bang.message}"
      end
      changes
    end


  end

  class << self; attr_accessor :changes end
  @changes ||= self.get_changes

end

Now I have finally reached critical mass in terms of the size of the file that is read in when this class is instantiated. I don't think I have set up the class variables correctly either.

When this class is called (not even instantiated, just constantized it's taking upwards of 8 seconds. And after it's been constantized, it's fine for a while. But I guess it gets cleared out of memory, and it has to be loaded again. Which takes another 8 seconds to a minute.

Ideally, it would load once when my application starts, and that would be that. Is there a way to do that? I appreciate your help as this is a particular weakness of mine. I need this data readily available. But if this doesn't work, would it be better to put this code in an initializer and load the file into constants? Thank you kindly for your help.

Upvotes: 0

Views: 60

Answers (1)

jiop
jiop

Reputation: 426

You can use a class variable (tagged with @@) to store data at a class level.

Moreover, you can apply the singleton pattern to your Catalog (https://en.wikipedia.org/wiki/Singleton_pattern).

As you said you have a lot of data, the second option is a better one.

Upvotes: 1

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