Seata
概念
Seata 是一款开源的分布式事务解决方案，致力于提供高性能和简单易用的分布式事务服务，提供了AT TCC、SAGA 和 XA 事务模式，默认是AT模式。
官网：http://seata.io/zh-cn/
术语
TC (Transaction Coordinator) - 事务协调者
维护全局和分支事务的状态，驱动全局事务提交或回滚。
TM (Transaction Manager) - 事务管理器
定义全局事务的范围：开始全局事务、提交或回滚全局事务。
RM (Resource Manager) - 资源管理器
管理分支事务处理的资源，与TC交谈以注册分支事务和报告分支事务的状态，并驱动分支事务提交或回滚。
机制
一阶段：业务数据和回滚日志记录在同一个本地事务中提交，释放本地锁和连接资源。
二阶段：
- 提交异步化，非常快速地完成。
- 回滚通过一阶段的回滚日志进行反向补偿。
seata把信息存储在前镜像、后镜像中，如果发生了异常，与后镜像对比如果数据没有被改写就回滚数据，否则需要人工修改
{ "branchId": 641789253, "undoItems": [{ "afterImage": { "rows": [{ "fields": [{ "name": "id", "type": 4, "value": 1 }, { "name": "name", "type": 12, "value": "GTS" }, { "name": "since", "type": 12, "value": "2014" }] }], "tableName": "product" }, "beforeImage": { "rows": [{ "fields": [{ "name": "id", "type": 4, "value": 1 }, { "name": "name", "type": 12, "value": "TXC" }, { "name": "since", "type": 12, "value": "2014" }] }], "tableName": "product" }, "sqlType": "UPDATE" }], "xid": "xid:xxx" }
执行过程
环境
- jdk11
- maven3.8.1
- SpringBoot 2.2.2
- SpringCloud Hoxton.SR1
- seata 1.0.0
- nacos 2.0.2
Seata
下载地址：http://seata.io/zh-cn/blog/download.html
配置
修改file.conf
如果使用的是高版本的mysql，把lib里面低版本的jar包删掉，不然一直报错：Could not create connection to database server
修改registry.conf文件
创建数据库seata，所依赖的表
-- the table to store GlobalSession data DROP TABLE IF EXISTS `global_table`; CREATE TABLE `global_table` ( `xid` VARCHAR(128) NOT NULL, `transaction_id` BIGINT, `status` TINYINT NOT NULL, `application_id` VARCHAR(32), `transaction_service_group` VARCHAR(32), `transaction_name` VARCHAR(128), `timeout` INT, `begin_time` BIGINT, `application_data` VARCHAR(2000), `gmt_create` DATETIME, `gmt_modified` DATETIME, PRIMARY KEY (`xid`), KEY `idx_gmt_modified_status` (`gmt_modified`, `status`), KEY `idx_transaction_id` (`transaction_id`) ); -- the table to store BranchSession data DROP TABLE IF EXISTS `branch_table`; CREATE TABLE `branch_table` ( `branch_id` BIGINT NOT NULL, `xid` VARCHAR(128) NOT NULL, `transaction_id` BIGINT , `resource_group_id` VARCHAR(32), `resource_id` VARCHAR(256) , `lock_key` VARCHAR(128) , `branch_type` VARCHAR(8) , `status` TINYINT, `client_id` VARCHAR(64), `application_data` VARCHAR(2000), `gmt_create` DATETIME, `gmt_modified` DATETIME, PRIMARY KEY (`branch_id`), KEY `idx_xid` (`xid`) ); -- the table to store lock data DROP TABLE IF EXISTS `lock_table`; CREATE TABLE `lock_table` ( `row_key` VARCHAR(128) NOT NULL, `xid` VARCHAR(96), `transaction_id` LONG , `branch_id` LONG, `resource_id` VARCHAR(256) , `table_name` VARCHAR(32) , `pk` VARCHAR(36) , `gmt_create` DATETIME , `gmt_modified` DATETIME, PRIMARY KEY(`row_key`) );
案例
业务数据库创建undo_log表
CREATE TABLE `undo_log` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `branch_id` bigint(20) NOT NULL, `xid` varchar(100) NOT NULL, `context` varchar(128) NOT NULL, `rollback_info` longblob NOT NULL, `log_status` int(11) NOT NULL, `log_created` datetime NOT NULL, `log_modified` datetime NOT NULL, `ext` varchar(100) DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
pom
<dependencies>
<!--nacos-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<!--seata-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-seata</artifactId>
<exclusions>
<exclusion>
<artifactId>seata-all</artifactId>
<groupId>io.seata</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.seata</groupId>
<artifactId>seata-all</artifactId>
<version>1.0.0</version>
</dependency>
<!--feign-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<!--web-actuator-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!--mysql-druid-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.10</version>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.0.0</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
yml
server: port: 2001 spring: application: name: seata-order-service cloud: alibaba: seata: #自定义事务组名称需要与seata-server中的对应 tx-service-group: fsp_tx_group nacos: discovery: server-addr: localhost:8848 datasource: driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://localhost:3306/seata_order?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8 username: root password: 123456 feign: hystrix: enabled: false logging: level: io: seata: info mybatis: mapperLocations: classpath:mapper/*.xml
把file.conf、registry.conf添加到资源路径下，file文件修改一处
这两个保持一致，然后使用一个 @GlobalTransactional 注解在业务方法上
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