MySQL XA配置简单易懂的实现方法

MySQL XA（两阶段提交）是一种分布式事务协议，用于确保多个数据库在执行事务时的数据一致性，在本文中，我们将介绍如何在MySQL中配置XA，并实现一个简单的示例。

1、安装MySQL XA插件

我们需要在MySQL服务器上安装XA插件，以下是在不同操作系统上安装XA插件的方法：

在Ubuntu或Debian系统上，可以使用以下命令安装：

sudo aptget install libmysqlxadev

在CentOS或RHEL系统上，可以使用以下命令安装：

sudo yum install mysqlcommunitylibs

2、创建XA事务表

接下来，我们需要创建一个用于存储XA事务信息的表，以下是创建XA事务表的SQL语句：

CREATE TABLE xa_transaction (
  id int(11) NOT NULL AUTO_INCREMENT,
  gid varchar(128) NOT NULL,
  data longblob NOT NULL,
  PRIMARY KEY (id),
  UNIQUE KEY ux_gid (gid)
) ENGINE=InnoDB;

3、启用XA支持

在MySQL配置文件（my.cnf或my.ini）中，添加以下内容以启用XA支持：

[mysqld]
defaultstorageengine=InnoDB
innodb_support_xa=1
innodb_enable_local_infile=1

然后重启MySQL服务以使更改生效。

4、编写XA应用程序

现在我们可以编写一个简单的XA应用程序来演示如何使用XA，以下是一个简单的Java程序，使用JDBC连接到两个MySQL服务器并执行一个XA事务：

import java.sql.*;
import javax.sql.XAConnection;
import javax.sql.XADataSource;
import javax.sql.XAException;
import javax.sql.XAResource;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public class XAExample {
    public static void main(String[] args) throws Exception {
        // 获取数据源
        Context initContext = new InitialContext();
        Context envContext = (Context) initContext.lookup("java:/comp/env");
        XADataSource ds = (XADataSource) envContext.lookup("jdbc/MysqlXADataSource");
        Connection conn1 = ds.getConnection();
        Connection conn2 = ds.getConnection();
        conn1.setAutoCommit(false);
        conn2.setAutoCommit(false);
        XAConnection xac1 = conn1.unwrap(XAConnection.class);
        XAConnection xac2 = conn2.unwrap(XAConnection.class);
        xac1.start();
        xac2.start();
        int transactionId = xac1.getTransaction().getTransactionIdentifier();
        System.out.println("Transaction ID: " + transactionId);
        Statement stmt1 = conn1.createStatement();
        Statement stmt2 = conn2.createStatement();
        stmt1.executeUpdate("INSERT INTO test_table (id, name) VALUES (1, 'test')");
        stmt2.executeUpdate("INSERT INTO test_table (id, name) VALUES (2, 'test')");
        xac1.commit(); // 提交事务，如果发生异常，则回滚事务并抛出异常
        xac2.commit(); // 提交事务，如果发生异常，则回滚事务并抛出异常
        conn1.close();
        conn2.close();
    }
}

5、运行XA应用程序

要运行此示例，您需要将MySQL服务器配置为支持XA事务，以下是如何配置MySQL服务器的步骤：

在第一个MySQL服务器上，创建一个用于存储XA事务日志的文件：

touch /var/lib/mysql/localhostrecoverylocal.ibd && chown R mysql:mysql /var/lib/mysql/localhostrecoverylocal.ibd && chmod R 700 /var/lib/mysql/localhostrecoverylocal.ibd && echo "SET GLOBAL innodb_undo_directory='/var/lib/mysql/'" >> /etc/mysql/my.cnf && echo "SET GLOBAL innodb_undo_logs=1" >> /etc/mysql/my.cnf && echo "SET GLOBAL innodb_undo_tablespaces='localhostrecoverylocal'" >> /etc/mysql/my.cnf && service mysql restart && echo "FLUSH PRIVILEGES" | mysql u root proot skippassword && echo "GRANT REPLICATION CLIENT ON *.* TO 'repl'@'%' IDENTIFIED BY 'password'" >> /etc/mysql/my.cnf && echo "GRANT ALL PRIVILEGES ON *.* TO 'repl'@'%' IDENTIFIED BY 'password'" >> /etc/mysql/my.cnf && echo "FLUSH PRIVILEGES" | mysql u root proot skippassword && bin/mysqld_safe user=mysql & bin/mysqld_safe user=mysql & sleep 60 && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_remote';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_xa';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_openssl';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_federated';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_blackhole';" && bin/mysql u rootprootskippasswordexecute="INSTALL SONAME 'ha_mroonga';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_ndbcluster';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_spider';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_binlog';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_archive';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_partition';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_rowbased';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_example';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_bookmark';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_secondary';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_proxy';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_ticket';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_temptable';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ha_recovery';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'binlog';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'blackhole';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'mroonga';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'ndbcluster';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'spider';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'binlog';" && bin/mysql u root proot skippassword execute="INSTALL SONAME 'archive';" && bin/mysql u root proot skippassword execute="INSTALL