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二、branch transaction

2022-05-17 20:19:09   2  举报

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AI智能生成

seata源码解析--分支事务注册、提交、回滚

Seata源码

Seata原理

作者其他创作

大纲/内容

springboot自动配置类SeataAutoConfiguration

RM添加如下配置：seata:
enabled: true
enable-auto-data-source-proxy: true

SeataDataSourceBeanPostProcessor

该类实现接口BeanPostProcessor

实现方法postProcessAfterInitialization，对原生的DataSOurce生成代理类：DataSourceProxy

SeataDataSourceBeanPostProcessor#proxyDataSource(Object originBean)，改方法中生成一个数据源的代理类:DataSourceProxy，并缓存到dataSourceProxyMap中

DataSourceProxy

继承类AbstractDataSourceProxy

实现接口DataSource

实现接口Resource

getConnection(String username, String password)，返回对象：ConnectionProxy

ConnectionProxy#ConnectionProxy(DataSourceProxy dataSourceProxy, Connection targetConnection)

AbstractConnectionProxy#AbstractConnectionProxy(DataSourceProxy dataSourceProxy, Connection targetConnection)

AbstractConnectionProxy#createStatement()

StatementProxy

AbstractConnectionProxy#prepareStatement(String sql)

PreparedStatementProxy

ConnectionProxy#commit(),提交事务

ConnectionProxy#doCommit()

// 在全局事务中，执行全局事务提交
ConnectionProxy# processGlobalTransactionCommit();

ConnectionProxy#register():

ConnectionProxy#recognizeLockKeyConflictException(TransactionException te, String lockKeys)recognizeLockKeyConflictException(TransactionException te, String lockKeys)

持久化前置镜像、后置镜像

AbstractUndoLogManager#flushUndoLogs(ConnectionProxy cp)

protected abstract void insertUndoLogWithNormal(String xid, long branchId, String rollbackCtx, byte[] undoLogContent,
Connection conn) throws SQLException;

抽象方法，由子类实现

ConnectionProxy#report(boolean commitDone)

AbstractResourceManager#branchReport(BranchType branchType, String xid, long branchId, BranchStatus status, String applicationData)使用RmRpcClient向TC服务端

// 获取到了全局锁
ConnectionProxy#processLocalCommitWithGlobalLocks();

// 普通事务提交
ConnectionProxy#targetConnection.commit();

DataSourceProxy dataSourceProxy = DataSourceProxyHolder.get().putDataSource((DataSource) originBean);

DataSourceProxyHolder#putDataSource(DataSource dataSource)

return this.dataSourceProxyMap.computeIfAbsent(dataSource, DataSourceProxy::new);

调用父类的构造方法AbstractDataSourceProxy#DataSourceProxy(DataSource targetDataSource, String resourceGroupId)

调用父类构造方法：AbstractDataSourceProxy#AbstractDataSourceProxy(DataSource targetDataSource)

DataSourceProxy#init(DataSource dataSource, String resourceGroupId)

实习方法postProcessBeforeInitialization