lol.rb

gem "activerecord", "4.2.4"
require "active_record"

ActiveRecord::Base.logger = Logger.new($stdout)

ActiveRecord::Base.establish_connection :adapter => "mysql2", :database => "test"

# ---------------------------------------------------------------------

ActiveRecord::Base.connection.transaction do
  ActiveRecord::Base.connection.transaction do
    ActiveRecord::Base.connection.execute("SELECT 1")
    raise ActiveRecord::Rollback
  end
end

# D, [2015-09-24T17:11:03.692672 #6838] DEBUG -- :    (0.1ms)  BEGIN
# D, [2015-09-24T17:11:03.692901 #6838] DEBUG -- :    (0.1ms)  SELECT 1
# D, [2015-09-24T17:11:03.693075 #6838] DEBUG -- :    (0.1ms)  COMMIT

# ---------------------------------------------------------------------

ActiveRecord::Base.connection.transaction do
  ActiveRecord::Base.connection.execute("SELECT 1")
  raise ActiveRecord::Rollback
end

# D, [2015-09-24T17:11:03.693277 #6838] DEBUG -- :    (0.1ms)  BEGIN
# D, [2015-09-24T17:11:03.693460 #6838] DEBUG -- :    (0.1ms)  SELECT 1
# D, [2015-09-24T17:11:03.693624 #6838] DEBUG -- :    (0.1ms)  ROLLBACK

# ---------------------------------------------------------------------