MySQL XA distributed transaction

Due to the splitting of various businesses of the system , Split multiple business services to different servers , Formed microservices . And in the actual production environment , We always encounter scenarios that require multiple microservices to jointly provide services , We also need to ensure that each microservice has the four characteristics of transactions （ Atomicity 、 Uniformity 、 Isolation, 、 persistence ）. A typical scenario involves placing an order 3 A service （ Member services 、 Order service 、 Goods and services ）. While placing an order , We need to ensure the successful creation of orders and the correct reduction of commodity inventory .

thus , I did some data preparation , Discover that distributed transactions can be used , What I am familiar with is tcc, But specifically tcc How is the underlying implementation of , I don't know , But I'll try again mysql The solution to this problem is found in the official documents of . namely XA Business .

About XA Please click here to explain the details of the transaction

Here are my tests , First we open two by command mysql Connect , And prepare the test table .

The above is my test data . I will use this data to test XA Business .

First step ：client1 Create a xa Business

xa start "mysql_xa_1";
update users set nickname='tanyong123' where id=1;
update users set versionId = 22 where id=1;
xa end "mysql_xa_1";
xa prepare "mysql_xa_1";

among mysql_xa_1 It's a business id, We always have to make sure that things id Uniqueness , Not to be repeated

I found that I have successfully created here ,

The second step ： establish client2 Verify that the data has been persisted to the file layer

Check what I just performed sql Whether the statement has been persisted to the file layer .
Open a new connection client2

You can find that just xa Transaction statements executed in are not persisted .

The third step ： To verify client2 Hold client1 The business of id Can I submit successfully

You can find , Submission failed . Is it because of my client1 The connection was not closed （ sign out ）, And lead to client2 Unable to submit successfully ？ Based on this , I did another test , sign out client1 Of mysql Connect . Let... Again client2 Perform transactions

It can be found from the figure that the submission was successful , We created client3 look down xa Whether the data submitted by the transaction is persisted to the file layer .

From this, we can see that it has been persisted to the file layer .

summary

Based on the above test , We know , When client1 Create good xa After the transaction, through the transaction id You can make client2 To commit a transaction .

Based on this principle , I designed a simple distributed transaction model diagram

Business side through restful or rpc Get xa Business id, Judge these according to the execution results of other businesses xa Transaction execution rollback or commit .

xa Transaction rollback command

xa rollback "mysql_xa_1" 

mysql_xa_1 For business id