Active Record 真实事务

# File activerecord/lib/active_record/connection_adapters/abstract/transaction.rb, line 487
def commit
  if materialized?
    connection.commit_db_transaction
    connection.reset_isolation_level if isolation_level
  end
  @state.full_commit!
  @instrumenter.finish(:commit) if materialized?
end

# File activerecord/lib/active_record/connection_adapters/abstract/transaction.rb, line 450
def materialize!
  if joinable?
    if isolation_level
      connection.begin_isolated_db_transaction(isolation_level)
    else
      connection.begin_db_transaction
    end
  else
    connection.begin_deferred_transaction(isolation_level)
  end

  super
end

# File activerecord/lib/active_record/connection_adapters/abstract/transaction.rb, line 464
def restart
  return unless materialized?

  @instrumenter.finish(:restart)

  if connection.supports_restart_db_transaction?
    @instrumenter.start
    connection.restart_db_transaction
  else
    connection.rollback_db_transaction
    materialize!
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract/transaction.rb, line 478
def rollback
  if materialized?
    connection.rollback_db_transaction
    connection.reset_isolation_level if isolation_level
  end
  @state.full_rollback!
  @instrumenter.finish(:rollback) if materialized?
end