Clearing ActiveRecord cache

To a first approximation:

ActiveRecord::Base.connection.query_cache.clear

We use:

ActiveRecord::Base.connection.query_cache.clear
(ActiveRecord::Base.connection.tables - %w[schema_migrations versions]).each do |table|
  table.classify.constantize.reset_column_information rescue nil
end

But I am not certain even this is enough.

Have a look at the method clear_query_cache in http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/QueryCache.html