是的，回调都包含在一个事务中.

Yes, the callbacks are all wrapped up in a transaction.

基本上，以下会导致回滚:

Basically, the following will cause a rollback:

• 从 before_save 或类似回调返回 false
• before_save 或类似回调中的异常
• after_save 或类似回调(after_create)中的异常

• return false from before_save or similar callbacks
• exception in before_save or similar callbacks
• exception in after_save or similar callbacks (after_create)

以下不会导致回滚:

• 从 after_save 或类似回调返回 false
• after_commit 中的异常

• return false from after_save or similar callbacks
• exception in after_commit

如果您不希望异常导致回滚，请使用 after_commit

If you don't want an exception to cause a rollback, use after_commit

• 参考:http://webonrails.com/2012/08/28/activerecord-after_commit-钩子/
• 附加参考:http://guides.rubyonrails.org/v3.1.3/active_record_validations_callbacks.html#transaction-callbacks