seata---分布式事务处理

Posted 2021-12-10 大忽悠爱忽悠

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seata---分布式事务处理

是什么
能干嘛
处理过程
Seata-Server安装
Seata之原理简介

是什么

Seata是一款开源的分布式事务解决方案，致力于在微服务架构下提供高性能和简单易用的分布式事务服务。

官方文档

能干嘛

一个典型的分布式事务过程

分布式事务处理过程的一ID+三组件模型：

Transaction ID XID 全局唯一的事务ID
三组件概念

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。

处理过程

TM向TC申请开启一个全局事务，全局事务创建成功并生成一个全局唯一的XID；
XID在微服务调用链路的上下文中传播；
RM向TC注册分支事务，将其纳入XID对应全局事务的管辖；
TM向TC发起针对XID的全局提交或回滚决议；
TC调度XID下管辖的全部分支事务完成提交或回滚请求。

Seata-Server安装

下载

怎么玩

本地@Transactional

全局@GlobalTransactional

SEATA 的分布式交易解决方案

我们只需要使用一个 @GlobalTransactional 注解在业务方法上:

安装

官网地址 - http://seata.io/zh-cn/

下载版本 - 0.9.0

seata-server-0.9.0.zip解压到指定目录并**修改conf目录下的file.conf配置文件**

先备份原始file.conf文件

主要修改:自定义事务组名称+事务日志存储模式为db +数据库连接信息

file.conf

修改service模块

service {
    ##fsp_tx_group是自定义的
    vgroup_mapping.my.test.tx_group="fsp_tx_group" 
    default.grouplist = "127.0.0.1:8091"
    enableDegrade = false
    disable = false
    max.commitretry.timeout= "-1"
    max.ollbackretry.timeout= "-1"
}

修改store模块

## transaction log store
store {
	## store mode: file, db
	## 改成db
	mode = "db"
	
	## file store
	file {
		dir = "sessionStore"
		
		# branch session size, if exceeded first try compress lockkey, still exceeded throws exceptions
		max-branch-session-size = 16384
		# globe session size, if exceeded throws exceptions
		max-global-session-size = 512
		# file buffer size, if exceeded allocate new buffer
		file-write-buffer-cache-size = 16384
		# when recover batch read size
		session.reload.read_size= 100
		# async, sync
		flush-disk-mode = async
	}

	# database store
	db {
		## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp) etc.
		datasource = "dbcp"
		## mysql/oracle/h2/oceanbase etc.
		## 配置数据源
		db-type = "mysql"
		driver-class-name = "com.mysql.jdbc.Driver"
		url = "jdbc:mysql://127.0.0.1:3306/seata"
		user = "root"
		password = "你自己密码"
		min-conn= 1
		max-conn = 3
		global.table = "global_table"
		branch.table = "branch_table"
		lock-table = "lock_table"
		query-limit = 100
	}
}

mysql5.7数据库新建库seata，在seata库里建表

建表db_store.sql在\\seata-server-0.9.0\\seata\\conf目录里面

-- 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`)
);

修改seata-server-0.9.0\\seata\\conf目录下的registry.conf配置文件

registry {
  # file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
  # 改用为nacos
  type = "nacos"

  nacos {
  	## 加端口号
    serverAddr = "localhost:8848"
    namespace = ""
    cluster = "default"
  }
  ...
}

目的是：指明注册中心为nacos，及修改nacos连接信息

先启动Nacos端口号8848 nacos\\bin\\startup.cmd

再启动seata-server - seata-server-0.9.0\\seata\\bin\\seata-server.bat

Seata业务数据库准备

以下演示都需要先启动Nacos后启动Seata,保证两个都OK。

分布式事务业务说明

这里我们会创建三个服务，一个订单服务，一个库存服务，一个账户服务。

当用户下单时,会在订单服务中创建一个订单, 然后通过远程调用库存服务来扣减下单商品的库存，再通过远程调用账户服务来扣减用户账户里面的余额，最后在订单服务中修改订单状态为已完成。

该操作跨越三个数据库，有两次远程调用，很明显会有分布式事务问题。

一言蔽之，下订单—>扣库存—>减账户(余额)。

创建业务数据库

seata_ order：存储订单的数据库;
seata_ storage：存储库存的数据库;
seata_ account：存储账户信息的数据库。

建库SQL

CREATE DATABASE seata_order;
CREATE DATABASE seata_storage;
CREATE DATABASE seata_account;

按照上述3库分别建对应业务表

seata_order库下建t_order表

CREATE TABLE t_order (
    `id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
    `user_id` BIGINT(11) DEFAULT NULL COMMENT '用户id',
    `product_id` BIGINT(11) DEFAULT NULL COMMENT '产品id',
    `count` INT(11) DEFAULT NULL COMMENT '数量',
    `money` DECIMAL(11,0) DEFAULT NULL COMMENT '金额',
    `status` INT(1) DEFAULT NULL COMMENT '订单状态: 0:创建中; 1:已完结',
) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

SELECT * FROM t_order;

seata_storage库下建t_storage表

CREATE TABLE t_storage (
`id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
`product_id` BIGINT(11) DEFAULT NULL COMMENT '产品id',
`total` INT(11) DEFAULT NULL COMMENT '总库存',
`used` INT(11) DEFAULT NULL COMMENT '已用库存',
`residue` INT(11) DEFAULT NULL COMMENT '剩余库存'
) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

INSERT INTO seata_storage.t_storage(`id`, `product_id`, `total`, `used`, `residue`)
VALUES ('1', '1', '100', '0','100');

SELECT * FROM t_storage;

seata_account库下建t_account表

CREATE TABLE t_account(
	`id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'id',
	`user_id` BIGINT(11) DEFAULT NULL COMMENT '用户id',
	`total` DECIMAL(10,0) DEFAULT NULL COMMENT '总额度',
	`used` DECIMAL(10,0) DEFAULT NULL COMMENT '已用余额',
	`residue` DECIMAL(10,0) DEFAULT '0' COMMENT '剩余可用额度'
) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

INSERT INTO seata_account.t_account(`id`, `user_id`, `total`, `used`, `residue`)
VALUES ('1', '1', '1000', '0', '1000');

SELECT * FROM t_account;

按照上述3库分别建对应的回滚日志表

订单-库存-账户3个库下都需要建各自的回滚日志表
\\seata-server-0.9.0\\seata\\conf目录下的db_ undo_ log.sql
建表SQL

-- the table to store seata xid data
-- 0.7.0+ add context
-- you must to init this sql for you business databese. the seata server not need it.
-- 此脚本必须初始化在你当前的业务数据库中，用于AT 模式XID记录。与server端无关（注：业务数据库）
-- 注意此处0.3.0+ 增加唯一索引 ux_undo_log
drop table `undo_log`;
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;

Seata之Order-Module配置搭建

下订单 -> 减库存 -> 扣余额 -> 改（订单）状态

seata-order-service2001

POM

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>cloud2020</artifactId>
        <groupId>com.atguigu.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>seata-order-service2001</artifactId>

    <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>0.9.0</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>
            <version>5.1.37</version>
        </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>

</project>

配置文件

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.jdbc.Driver
    url: jdbc:mysql://localhost:3306/seata_order
    username: root
    password: 123456

feign:
  hystrix:
    enabled: false

logging:
  level:
    io:
      seata: info

mybatis:
  mapperLocations: classpath:mapper/*.xml

file.conf

transport {
  # tcp udt unix-domain-socket
  type = "TCP"
  #NIO NATIVE
  server = "NIO"
  #enable heartbeat
  heartbeat = true
  #thread factory for netty
  thread-factory {
    boss-thread-prefix = "NettyBoss"
    worker-thread-prefix = "NettyServerNIOWorker"
    server-executor-thread-prefix = "NettyServerBizHandler"
    share-boss-worker = false
    client-selector-thread-prefix = "NettyClientSelector"
    client-selector-thread-size = 1
    client-worker-thread-prefix = "NettyClientWorkerThread"
    # netty boss thread size,will not be used for UDT
    boss-thread-size = 1
    #auto default pin or 8
    worker-thread-size = 8
  }
  shutdown {
    # when destroy server, wait seconds
    wait = 3
  }
  serialization = "seata"
  compressor = "none"
}

service {

  vgroup_mapping.fsp_tx_group = "default" #修改自定义事务组名称

  default.grouplist = "127.0.0.1:8091"
  enableDegrade = false
  disable = false
  max.commit.retry.timeout = "-1"
  max.rollback.retry.timeout = "-1"
  disableGlobalTransaction = false
}


client {
  async.commit.buffer.limit = 10000
  lock {
    retry.internal = 10
    retry.times = 30
  }
  report.retry.count = 5
  tm.commit.retry.count = 1
  tm.rollback.retry.count = 1
}

## transaction log store
store {
  ## store mode: file、db
  mode = "db"

  ## file store
  file {
    dir = "sessionStore"

    # branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
    max-branch-session-size = 16384
    # globe session size , if exceeded throws exceptions
    max-global-session-size = 512
    # file buffer size , if exceeded allocate new buffer
    file-write-buffer-cache-size = 16384
    # when recover batch read size
    session.reload.read_size = 100
    # async, sync
    flush-disk-mode = async
  }

  ## database store
  db {
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