Seata分布式事务实践

#  Copyright 1999-2019 Seata.io Group.
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#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
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#  http://www.apache.org/licenses/LICENSE-2.0
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#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.server:port: 7091spring:application:name: seata-serverlogging:config: classpath:logback-spring.xmlfile:path: ${log.home:${user.home}/logs/seata}extend:logstash-appender:destination: 127.0.0.1:4560kafka-appender:bootstrap-servers: 127.0.0.1:9092topic: logback_to_logstashconsole:user:username: seatapassword: seata
seata:config:# support: nacos 、 consul 、 apollo 、 zk  、 etcd3type: nacos #使用nacos作为配置中心nacos:server-addr: 127.0.0.1:8088namespace: 01025263-d24e-4558-a2a1-2448142e9d57 #nacos命名空间id,""为nacos保留public空间空间group: DEFAULT_GROUP #指定配置至nacos注册中心的分组名#username:#password:#context-path:##if use MSE Nacos with auth, mutex with username/password attribute#access-key:#secret-key:data-id: seataServer.propertiesregistry:# support: nacos 、 eureka 、 redis 、 zk  、 consul 、 etcd3 、 sofatype: nacos #使用nacos作为注册中心nacos:application: seata-server #指定注册至nacos注册中心的服务名server-addr: 127.0.0.1:8088group: DEFAULT_GROUPnamespace: 01025263-d24e-4558-a2a1-2448142e9d57cluster: default #指定注册至nacos注册中心的集群名，与配置中心文件中的service.vgroupMapping.[事务分组配置项]=TC集群的名称保持一致#username:#password:#context-path:##if use MSE Nacos with auth, mutex with username/password attribute#access-key:#secret-key:#store:# support: file 、 db 、 redis 、 raft#mode: db#  server:#    service-port: 8091 #If not configured, the default is '${server.port} + 1000'security:secretKey: SeataSecretKey0c382ef121d778043159209298fd40bf3850a017tokenValidityInMilliseconds: 1800000ignore:urls: /,/**/*.css,/**/*.js,/**/*.html,/**/*.map,/**/*.svg,/**/*.png,/**/*.jpeg,/**/*.ico,/api/v1/auth/login,/metadata/v1/**

#存储方式为db
store.db.datasource=druid
store.db.dbType=mysql
#store.db.driverClassName=com.mysql.jdbc.Driver
#store.db.url=jdbc:mysql://127.0.0.1:3306/seata?useUnicode=true&rewriteBatchedStatements=true
#我的mysql版本为8.0
store.db.driverClassName=com.mysql.cj.jdbc.Driver
store.db.url=jdbc:mysql://127.0.0.1:3306/seata?useUnicode=true&rewriteBatchedStatements=true&serverTimezone=GMT%2B8
store.db.user=root
store.db.password=root12345

-- -------------------------------- The script used when storeMode is 'db' --------------------------------
-- the table to store GlobalSession data
create database if not exists seata DEFAULT CHARACTER SET utf8mb4;
use seata;
CREATE TABLE IF NOT EXISTS `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_status_gmt_modified` (`status` , `gmt_modified`),KEY `idx_transaction_id` (`transaction_id`)
) ENGINE = InnoDBDEFAULT CHARSET = utf8mb4;-- the table to store BranchSession data
CREATE TABLE IF NOT EXISTS `branch_table`
(`branch_id`         BIGINT       NOT NULL,`xid`               VARCHAR(128) NOT NULL,`transaction_id`    BIGINT,`resource_group_id` VARCHAR(32),`resource_id`       VARCHAR(256),`branch_type`       VARCHAR(8),`status`            TINYINT,`client_id`         VARCHAR(64),`application_data`  VARCHAR(2000),`gmt_create`        DATETIME(6),`gmt_modified`      DATETIME(6),PRIMARY KEY (`branch_id`),KEY `idx_xid` (`xid`)
) ENGINE = InnoDBDEFAULT CHARSET = utf8mb4;-- the table to store lock data
CREATE TABLE IF NOT EXISTS `lock_table`
(`row_key`        VARCHAR(128) NOT NULL,`xid`            VARCHAR(128),`transaction_id` BIGINT,`branch_id`      BIGINT       NOT NULL,`resource_id`    VARCHAR(256),`table_name`     VARCHAR(32),`pk`             VARCHAR(36),`status`         TINYINT      NOT NULL DEFAULT '0' COMMENT '0:locked ,1:rollbacking',`gmt_create`     DATETIME,`gmt_modified`   DATETIME,PRIMARY KEY (`row_key`),KEY `idx_status` (`status`),KEY `idx_branch_id` (`branch_id`),KEY `idx_xid` (`xid`)
) ENGINE = InnoDBDEFAULT CHARSET = utf8mb4;CREATE TABLE IF NOT EXISTS `distributed_lock`
(`lock_key`       CHAR(20) NOT NULL,`lock_value`     VARCHAR(20) NOT NULL,`expire`         BIGINT,primary key (`lock_key`)
) ENGINE = InnoDBDEFAULT CHARSET = utf8mb4;INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('AsyncCommitting', ' ', 0);
INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('RetryCommitting', ' ', 0);
INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('RetryRollbacking', ' ', 0);
INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('TxTimeoutCheck', ' ', 0);

./seata-server.sh -h 127.0.0.1 -p 8091

 <!--引入seata--><dependency><groupId>io.seata</groupId><artifactId>seata-spring-boot-starter</artifactId><version>${io.seata.version}</version><exclusions><exclusion><groupId>io.netty</groupId><artifactId>netty-all</artifactId></exclusion></exclusions></dependency><dependency><groupId>io.netty</groupId><artifactId>netty-all</artifactId><version>4.1.73.Final</version></dependency><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-seata</artifactId><version>${spring-cloud-alibaba.version}</version><exclusions><exclusion><groupId>io.seata</groupId><artifactId>seata-spring-boot-starter</artifactId></exclusion></exclusions></dependency>

server:port: 9990
spring:application:name: dc-userprofiles:active: localcloud:nacos:discovery:server-addr: 192.168.31.186:8088namespace: 01025263-d24e-4558-a2a1-2448142e9d57config:server-addr: 192.168.31.186:8088namespace: 01025263-d24e-4558-a2a1-2448142e9d57group: DEFAULT_GROUPprefix: ${spring.application.name}file-extension: yaml
#seata配置alibaba:seata:tx-service-group: vmi-service-group #事务分组需要和服务端配置文件中一致
seata:enabled: true  # 是否开启seata，默认true#enable-auto-data-source-proxy: true #数据源自动代理#tx-service-group: vmi-service-group #事务分组需要和服务端配置文件中一致,这个配置无效可删除data-source-proxy-mode: ATservice:#开启全局事务，默认为false开启#disable-global-transaction: false#可以不需要vgroup-mapping:vmi-service-group: default #事务分组需要和服务端配置文件中一致registry:type: nacosnacos:application : seata-servernamespace: 01025263-d24e-4558-a2a1-2448142e9d57serverAddr : 127.0.0.1:8088group : DEFAULT_GROUPcluster : default#username : nacos#password : nacosconfig:type: nacosnacos:server-addr: 127.0.0.1:8088namespace: 01025263-d24e-4558-a2a1-2448142e9d57group: DEFAULT_GROUP#username: nacos#password: nacosdata-id: seataServer.properties

spring:cloud:alibaba:seata:tx-service-group: vmi_tx_group #事务分组需要和服务端配置文件中一致seata:service:vgroup-mapping:vmi_tx_group: default #事务分组需要和服务端配置文件中一致

seata:data-source-proxy-mode: XA

 @GlobalTransactionalpublic BaseResponse hello(VerifyRegisterDto dto) {IdentityDocument identityDocument=new IdentityDocument();identityDocument.setIdentityName(dto.getUserName()); //证件类型名identityDocument.setIdPictureDescOne("证件图片描述1"); // 证件图片描述1identityDocument.setIdPictureDescTwo(dto.getUserName()); //证件图片描述2// 证件信息保存identityDocumentMapper.insert(identityDocument);PSysUser sysUser = new PSysUser();sysUser.setUserName(dto.getUserName());sysUser.setPhone(dto.getPhone());sysUser.setRoleId(2);sysUser.setUid(UIDUtil.getUUID());sysUser.setUserId(UIDUtil.nextId());String salt = UIDUtil.getUUID();sysUser.setSalt(salt);String md5Password = DigestUtils.md5Hex(salt + dto.getPassword());sysUser.setPassword(md5Password);// 保存用户信息sysUserMapper.insertSelective(sysUser);return ResultUtil.success();}

-- ----------------------------
-- Table structure for undo_log
-- ----------------------------
DROP TABLE IF EXISTS `undo_log`;
CREATE TABLE `undo_log`  (`branch_id` bigint(20) NOT NULL COMMENT 'branch transaction id',`xid` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT 'global transaction id',`context` varchar(128) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT 'undo_log context,such as serialization',`rollback_info` longblob NOT NULL COMMENT 'rollback info',`log_status` int(11) NOT NULL COMMENT '0:normal status,1:defense status',`log_created` datetime(6) NOT NULL COMMENT 'create datetime',`log_modified` datetime(6) NOT NULL COMMENT 'modify datetime',UNIQUE INDEX `ux_undo_log`(`xid`, `branch_id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = 'AT transaction mode undo table' ROW_FORMAT = Compact;

seata:data-source-proxy-mode: AT # 默认就是AT

 @GlobalTransactionalpublic BaseResponse hello(VerifyRegisterDto dto) {IdentityDocument identityDocument=new IdentityDocument();identityDocument.setIdentityName(dto.getUserName()); //证件类型名identityDocument.setIdPictureDescOne("证件图片描述1"); // 证件图片描述1identityDocument.setIdPictureDescTwo(dto.getUserName()); //证件图片描述2// 证件信息保存identityDocumentMapper.insert(identityDocument);PSysUser sysUser = new PSysUser();sysUser.setUserName(dto.getUserName());sysUser.setPhone(dto.getPhone());sysUser.setRoleId(2);sysUser.setUid(UIDUtil.getUUID());sysUser.setUserId(UIDUtil.nextId());String salt = UIDUtil.getUUID();sysUser.setSalt(salt);String md5Password = DigestUtils.md5Hex(salt + dto.getPassword());sysUser.setPassword(md5Password);// 保存用户信息sysUserMapper.insertSelective(sysUser);return ResultUtil.success();}

{"@class": "io.seata.rm.datasource.undo.BranchUndoLog","xid": "192.168.31.186:8091:3558411956758468259","branchId": 3558411956758468261,"sqlUndoLogs": ["java.util.ArrayList", [{"@class": "io.seata.rm.datasource.undo.SQLUndoLog","sqlType": "INSERT","tableName": "userbusiness.identity_document","beforeImage": {"@class": "io.seata.rm.datasource.sql.struct.TableRecords$EmptyTableRecords","tableName": "identity_document","rows": ["java.util.ArrayList", []]},"afterImage": {"@class": "io.seata.rm.datasource.sql.struct.TableRecords","tableName": "identity_document","rows": ["java.util.ArrayList", [{"@class": "io.seata.rm.datasource.sql.struct.Row","fields": ["java.util.ArrayList", [{"@class": "io.seata.rm.datasource.sql.struct.Field","name": "id","keyType": "PRIMARY_KEY","type": 4,"value": 15}, {"@class": "io.seata.rm.datasource.sql.struct.Field","name": "identity_name","keyType": "NULL","type": 12,"value": "aaa333"}, {"@class": "io.seata.rm.datasource.sql.struct.Field","name": "Id_picture_desc_one","keyType": "NULL","type": 12,"value": "证件图片描述1"}, {"@class": "io.seata.rm.datasource.sql.struct.Field","name": "Id_picture_desc_two","keyType": "NULL","type": 12,"value": "aaa333"}, {"@class": "io.seata.rm.datasource.sql.struct.Field","name": "create_time","keyType": "NULL","type": 93,"value": null}, {"@class": "io.seata.rm.datasource.sql.struct.Field","name": "update_time","keyType": "NULL","type": 93,"value": null}]]}]]}}]]
}

		1. 将user表id为1的用户的旧值冻结起来(这条数据状态设置为0，代表处于try状态)，便于后续回滚补偿。2. 将user表id为1的用户name值更新。

@LocalTCC
public interface SystemTCCService {@TwoPhaseBusinessAction(name = "doTry", commitMethod = "confirm", rollbackMethod = "cancel")void doTry(@BusinessActionContextParameter(paramName = "id") String id,@BusinessActionContextParameter(paramName = "oldVal") String oldVal,@BusinessActionContextParameter(paramName = "val") String val);boolean confirm(BusinessActionContext ctx);boolean cancel(BusinessActionContext ctx);}

@Service
public class SystemTCCServiceImpl implements SystemTCCService {@Autowiredprivate UserMapper userMapper;@Autowiredprivate SystemFreezeTblMapper systemFreezeTblMapper;@Overridepublic void doTry(String id, String oldVal,String val) {// 0.获取事务idString xid = RootContext.getXID();// 业务悬挂判断： 判断freeze中是否有冻结记录，如果有，一定是cancel执行过，拒绝业务操作if (systemFreezeTblMapper.selectByPrimaryKey(xid) != null) {// cancel执行过，我要拒绝业务return;}User user = new User();user.setId(id);user.setLoginName(val);user.setName(val);user.setPassword(val);userMapper.updateByPrimaryKeySelective(user);//冻结住原有的值SystemFreezeTbl systemFreezeTbl = new SystemFreezeTbl();systemFreezeTbl.setXid(xid);systemFreezeTbl.setUserId(user.getId());systemFreezeTbl.setFreezeVal(user.getName());systemFreezeTbl.setFreezeOldVal(oldVal);//0 try 1 confim 2 cancelsystemFreezeTbl.setState(0);systemFreezeTblMapper.insert(systemFreezeTbl);}@Overridepublic boolean confirm(BusinessActionContext ctx) {//成功则删除冻结的表String xid = ctx.getXid();int count = systemFreezeTblMapper.deleteByPrimaryKey(xid);return count > 0;}@Overridepublic boolean cancel(BusinessActionContext ctx) {// 0.查询冻结记录String xid = ctx.getXid();// 根据id查询冻结表的记录SystemFreezeTbl freeze = systemFreezeTblMapper.selectByPrimaryKey(xid);// 处理空回滚if (freeze == null) {//空回滚freeze = new SystemFreezeTbl();String userId = ctx.getActionContext("id").toString();freeze.setUserId(userId);freeze.setFreezeVal(ctx.getActionContext("val").toString());freeze.setFreezeOldVal(ctx.getActionContext("oldVal").toString());freeze.setState(2);freeze.setXid(xid);systemFreezeTblMapper.insert(freeze);return true;}// 幂等判断if (freeze.getState() == 2) {// 已经处理过了cancel，无需重复return true;}//手动补偿user表，进行数据还原User user = new User();user.setId(ctx.getActionContext("id").toString());user.setName(freeze.getFreezeOldVal());userMapper.updateByPrimaryKeySelective(user);//将资源冻结表状态设置为2 代表已取消freeze.setFreezeVal("");freeze.setState(2);int count = systemFreezeTblMapper.updateByPrimaryKey(freeze);return count > 0;}
}

@GetMapping("/test")@GlobalTransactionalpublic String hello() {systemTCCService.doTry("1", "1", "2");fileService.hello();return "success";}

	1. 基于事件驱动实现异步调用，性能较好，吞吐高。2. 一阶段直接提交事务，无锁，性能较好。3. 无需像TCC一样手动编写不同阶段的方法。

 1. 软状态时间不确定，时效性较差。2. 无事务隔离，可能出现脏写的情况。