dirty_tracking.rb

# frozen_string_literal: true

require"active_record"

ActiveRecord::Base.establish_connection(adapter: "sqlite3",database: ":memory:")

ActiveRecord::Schema.definedo
create_table:users,force: truedo |t|
t.string:name
t.timestampsnull: false
end

create_table:topics,force: truedo |t|
t.string:title
t.integer:user_id
t.timestampsnull: false
end
end

classTopic < ActiveRecord::Base
belongs_to:user
end

classUser < ActiveRecord::Base
has_many:topics
end

user=User.create!(name: "user name")
topic=user.topics.build(title: "topic title")

# Benchmark.ips do |x|
# x.report("changed?") { topic.changed? }
# x.report("changed") { topic.changed }
# x.report("changes") { topic.changes }
# x.report("changed_attributes") { topic.changed_attributes }
# x.report("title_change") { topic.title_change }
# x.report("title_was") { topic.title_was }
# end

Benchmark.bm{ |x|
x.report("title_was"){
1_000_000.times{
topic.title_was
}
}
}