Using .association(name).loaded?

Using .association(name).loaded?This method checks if a specific association has been loaded for a single record.
erb
<% if @post.association(:topic).loaded? %>
  <p>The topic association was eager loaded.</p>
<% else %>
  <p>The topic association was not eager loaded.</p>
<% end %>
Use code with caution.
  • @post.association(:topic): Gets the association object for the topic association.
  • .loaded?: Checks if the association's records have been loaded into memory.
Using item.association_cache.keysThis method gives you a list of the eager loaded associations for a given record.
erb
<% if @post.association_cache.keys.include?(:topic) %>
  <p>The topic association was eager loaded.</p>
<% else %>
  <p>The topic association was not eager loaded.</p>
<% end %>
Use code with caution.
  • @post.association_cache.keys: Returns an array of symbols representing the eager loaded associations.
Using Bullet Gem (for Development)The Bullet gem is specifically designed to detect N+1 query problems and unused eager loading. It will visually alert you (often with a popup or in the console) when it detects potential issues.
  • Installation:
    Add gem 'bullet', group: 'development' to your Gemfile.
    Run bundle install.
    Generate the configuration file: bundle exec rails g bullet:install.
  • Configuration:
    Configure Bullet in config/environments/development.rb:
    ruby
  • config.after_initialize do
  Bullet.enable = true
  Bullet.alert = true # Or configure other alert options
  # More options available
end
  • Use code with caution.
  • How it helps: Bullet will monitor your application's database queries and notify you in the browser or console when it detects potential N+1 query issues or unused eager loading.
Checking Server Logs (Development)The Rails server logs will show you the SQL queries being executed. If you see repeated queries for the same association (like retrieving a topic for each post individually), it indicates that eager loading is not working as expected. 
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