Alipay DTS architecture

lately , Busy doing a task , It's strange to find the business behind the scenes , Payment and cancellation are not in the same transaction .

According to my theory , Payment and write off are database businesses , Obviously, it should be in a transaction , To ensure the consistency of data .

After communicating with the person in charge of the backstage , Tell me that payment and cancellation are really two processes . As a software manufacturer , I can only be responsible for the consistency of my own affairs , However, the consistency of software services provided by other manufacturers cannot be guaranteed .

This statement , It seems to convince me , But it doesn't seem to be the best solution .

Theoretically , The above transactions belong to distributed transactions . Distributed transactions , Generally, it adopts two stages （2PC）; That is, the first paragraph is submitted , Then submit the second paragraph . But this way , It will cause all stages to be in the blocking stage , Cause the whole computer to go wrong .

Later, it was found that Alipay has a distributed transaction mechanism , Worth learning .

Distributed transaction service （Distributed Transaction Service, abbreviation DTS） Is a distributed transaction framework , To ensure the final consistency of transactions in a large-scale distributed environment .DTS From the perspective of Architecture xts-client and xts-server Two parts , The former is an embedded client application Jar package , Mainly responsible for writing and processing transaction data ; The latter is an independent system , Mainly responsible for the recovery of abnormal transactions .

in other words ,DTS Is characterized by ：

1） Final agreement ： In the course of a transaction , There will be brief inconsistencies , But by restoring the system , Reach final agreement .

2） Simple protocol ： It defines something like 2PC Standard two-phase interface for , You can use DTS Transactional function .

3） And RPC It's not about the service agreement ： hold DB Operation is defined as service, Nothing to do with the underlying protocol .

4） Independent of the underlying transaction implementation ： DTS It's an abstraction based on Service The concept of layers , Independent of the underlying transaction implementation , That is to say DTS Within the scope of , Either a relational database MySQL,Oracle, still KV Storage MemCache, Or column storage database HBase, As long as its operation is packaged as DTS Participants , You can access DTS Within the scope of business .

Exactly ,DTS It's a flexible business , That is to pursue the final consistency .

of DTS Documents , Please look at this information ：https://github.com/nyankosama/slidesShare/blob/master/%E5%A4%A7%E8%A7%84%E6%A8%A1SOA%E7%B3%BB%E7%BB%9F%E4%B8%AD%E7%9A%84%E5%88%86%E5%B8%83%E4%BA%8B%E5%8A%A1%E5%A4%84%E4%BA%8B_%E7%A8%8B%E7%AB%8B.pdf