两天，我把分布式事务搞完了

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C，只有 A - B 和 B - C 都买到票了才有意义。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"这时候的选择就没得 Try 了，直接调用航空公司的买票操作，当两个航空公司都买成功了那就直接成功了，如果某个公司买失败了，那就需要调用取消订票接口。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"也就是在第一阶段直接就执行完整个业务操作了，所以要重点关注回滚操作，如果回滚失败得有提醒，要人工介入等。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"这其实就是 TCC 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RocketMQ 、Kafka 的事务消息实现，以及两者之间的区别。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在这里我不再详细阐述，因为之前的文章写的很详细了，大概四五千字吧。我就附上链接了："},{"type":"link","attrs":{"href":"https://mp.weixin.qq.com/s/GX5nTl3LhkAj-XCj00rvHw","title":""},"content":[{"type":"text","text":"事务消息"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"Seata 的实现"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"首先什么是 Seata 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，再得到执行后的数据镜像，然后把这些数据组装成回滚日志。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"再伴随的这个本地事务的提交把回滚日志也插入到数据库的 UNDO"},{"type":"text","marks":[{"type":"italic"}],"text":"LOG 表中(所以数据库需要有一张UNDO"},{"type":"text","text":"LOG 表)。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"这波操作下来在一阶段就可以没有后顾之忧的提交事务了。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"然后一阶段如果成功，那么二阶段可以异步的删除那些回滚日志，如果一阶段失败那么可以通过回滚日志来反向补偿恢复。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"这时候有细心的同学想到了，万一中间有人改了这条数据怎么办？你这镜像就不对了啊？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"所以说还有个全局锁的概念，"},{"type":"text","marks":[{"type":"strong"}],"text":"在事务提交前需要拿到全局锁"},{"type":"text","text":"（可以理解为对这条数据的锁），然后才能顺利提交本地事务。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"如果一直拿不到那就需要回滚本地事务了。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"官网的示例很好，我就不自己编了，以下部分内容摘抄自 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