1.分布式事务问题
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一次业务操作需要跨多个数据源或需要跨多个系统进行远程调用，就会产生分布式事务问题.
2.Seata简介
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
官网地址：http://seata.io/zh-cn/
分布式事务处理过程的-ID+三组件模型
Transaction ID XID，全局唯一的事务ID
3组件概念：
Transaction Coordinator(TC)
事务协调器，维护全局事务的运行状态，负责协调并驱动全局事务的提交或回滚;
Transaction Manager(TM)
控制全局事务的边界，负责开启一个全局事务，并最终发起全局提交或全局回滚的决议;
Resource Manager(RM)
控制分支事务，负责分支注册，状态汇报，并接收事务协调器的指令，驱动分支（本地）事务的提交和回滚；
处理过程：
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Spring 本地@Transactional
全局@GlobalTransactional
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3.Seata-Server安装
下载版本：http://seata.io/zh-cn/ (1.3.0v) 解压到指定目录
下载源码：拷贝server和client，.sql文件到conf目录，创建seate数据库和表（server）
https://github.com/seata/seata/blob/1.3.0/script/server/db/mysql.sql
3.1SERVER 配置
3.1.1修改conf目录下registry.conf（先备份原始registry.conf文件）
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
#配置nacos作为seata-server注册中心
type = "nacos"
nacos {
application = "seata-server"
serverAddr = "192.168.1.111:1111"
group = "DEV_GROUP"
namespace = "300c5dc3-6326-4033-8d7e-effe12645735"
cluster = "default"
username = "nacos"
password = "nacos"
}
eureka {
serviceUrl = "http://localhost:8761/eureka"
application = "default"
weight = "1"
}
redis {
serverAddr = "localhost:6379"
db = 0
password = ""
cluster = "default"
timeout = 0
}
zk {
cluster = "default"
serverAddr = "127.0.0.1:2181"
sessionTimeout = 6000
connectTimeout = 2000
username = ""
password = ""
}
consul {
cluster = "default"
serverAddr = "127.0.0.1:8500"
}
etcd3 {
cluster = "default"
serverAddr = "http://localhost:2379"
}
sofa {
serverAddr = "127.0.0.1:9603"
application = "default"
region = "DEFAULT_ZONE"
datacenter = "DefaultDataCenter"
cluster = "default"
group = "SEATA_GROUP"
addressWaitTime = "3000"
}
file {
name = "file.conf"
}
}
config {
# file、nacos 、apollo、zk、consul、etcd3
#配置nacos为配置中心，如果配置file ，启用file.conf文件
type = "nacos"
nacos {
serverAddr = "192.168.1.111:1111"
namespace = "300c5dc3-6326-4033-8d7e-effe12645735"
group = "DEV_GROUP"
username = "nacos"
password = "nacos"
}
consul {
serverAddr = "127.0.0.1:8500"
}
apollo {
appId = "seata-server"
apolloMeta = "http://192.168.1.204:8801"
namespace = "application"
}
zk {
serverAddr = "127.0.0.1:2181"
sessionTimeout = 6000
connectTimeout = 2000
username = ""
password = ""
}
etcd3 {
serverAddr = "http://localhost:2379"
}
file {
name = "file.conf"
}
}
3.1.2registry.conf中配置中心配置file，需要修改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
## transaction log store, only used in seata-server
store {
## store mode: file、db、redis
#事务日志存储模式为db
mode = "db"
## file store property
file {
## store location dir
dir = "sessionStore"
# branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
maxBranchSessionSize = 16384
# globe session size , if exceeded throws exceptions
maxGlobalSessionSize = 512
# file buffer size , if exceeded allocate new buffer
fileWriteBufferCacheSize = 16384
# when recover batch read size
sessionReloadReadSize = 100
# async, sync
flushDiskMode = async
}
## database store property
#数据库连接信息
db {
## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp)/HikariDataSource(hikari) etc.
datasource = "druid"
## mysql/oracle/postgresql/h2/oceanbase etc.
dbType = "mysql"
driverClassName = "com.mysql.jdbc.Driver"
url = "jdbc:mysql://192.168.1.115:3306/seata"
user = "root"
password = "123456"
minConn = 5
maxConn = 30
globalTable = "global_table"
branchTable = "branch_table"
lockTable = "lock_table"
queryLimit = 100
maxWait = 5000
}
## redis store property
redis {
host = "127.0.0.1"
port = "6379"
password = ""
database = "0"
minConn = 1
maxConn = 10
queryLimit = 100
}
}
3.1.3registry.conf中配置中心配置nacos
上传配置至Nacos配置中心
参考https://github.com/seata/seata/tree/develop/script/config-center 的config.txt, 拷贝config.txt和nacos-config.sh到seata-server,
修改config.txt
transport.type=TCP
transport.server=NIO
transport.heartbeat=true
transport.enableClientBatchSendRequest=false
transport.threadFactory.bossThreadPrefix=NettyBoss
transport.threadFactory.workerThreadPrefix=NettyServerNIOWorker
transport.threadFactory.serverExecutorThreadPrefix=NettyServerBizHandler
transport.threadFactory.shareBossWorker=false
transport.threadFactory.clientSelectorThreadPrefix=NettyClientSelector
transport.threadFactory.clientSelectorThreadSize=1
transport.threadFactory.clientWorkerThreadPrefix=NettyClientWorkerThread
transport.threadFactory.bossThreadSize=1
transport.threadFactory.workerThreadSize=default
transport.shutdown.wait=3
#修改fsp-tx-group事务组名称为default，
#fsp-tx-group和微服务配置一致spring.cloud.alibaba.seata.tx-service-group=fsp-tx-group
#注意高版本vgroupMapping
service.vgroupMapping.fsp-tx-group=default
service.default.grouplist=192.168.1.114:8091
service.enableDegrade=false
service.disableGlobalTransaction=false
client.rm.asyncCommitBufferLimit=10000
client.rm.lock.retryInterval=10
client.rm.lock.retryTimes=30
client.rm.lock.retryPolicyBranchRollbackOnConflict=true
client.rm.reportRetryCount=5
client.rm.tableMetaCheckEnable=false
client.rm.sqlParserType=druid
client.rm.reportSuccessEnable=false
client.rm.sagaBranchRegisterEnable=false
client.tm.commitRetryCount=5
client.tm.rollbackRetryCount=5
client.tm.degradeCheck=false
client.tm.degradeCheckAllowTimes=10
client.tm.degradeCheckPeriod=2000
#配置事务日志模式db
store.mode=db
store.file.dir=file_store/data
store.file.maxBranchSessionSize=16384
store.file.maxGlobalSessionSize=512
store.file.fileWriteBufferCacheSize=16384
store.file.flushDiskMode=async
store.file.sessionReloadReadSize=100
store.db.datasource=druid
store.db.dbType=mysql
store.db.driverClassName=com.mysql.jdbc.Driver
#配置数据源
store.db.url=jdbc:mysql://192.168.1.115:3306/seata?useUnicode=true
store.db.user=root
store.db.password=123456
store.db.minConn=5
store.db.maxConn=30
store.db.globalTable=global_table
store.db.branchTable=branch_table
store.db.queryLimit=100
store.db.lockTable=lock_table
store.db.maxWait=5000
store.redis.host=127.0.0.1
store.redis.port=6379
store.redis.maxConn=10
store.redis.minConn=1
store.redis.database=0
store.redis.password=null
store.redis.queryLimit=100
server.recovery.committingRetryPeriod=1000
server.recovery.asynCommittingRetryPeriod=1000
server.recovery.rollbackingRetryPeriod=1000
server.recovery.timeoutRetryPeriod=1000
server.maxCommitRetryTimeout=-1
server.maxRollbackRetryTimeout=-1
server.rollbackRetryTimeoutUnlockEnable=false
client.undo.dataValidation=true
client.undo.logSerialization=jackson
client.undo.onlyCareUpdateColumns=true
server.undo.logSaveDays=7
server.undo.logDeletePeriod=86400000
client.undo.logTable=undo_log
client.log.exceptionRate=100
transport.serialization=seata
transport.compressor=none
metrics.enabled=false
metrics.registryType=compact
metrics.exporterList=prometheus
metrics.exporterPrometheusPort=9898
3.1.4配置信息提交到nacos
运行仓库中提供的nacos脚本./nacos-config.sh,将信息提交到nacos控制台,如果有需要更改,可直接通过控制台更改.
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3.1.5随后,启动 Seata-Server
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您同样也能发现Server 和Client部分配置都已经从配置中心中读取,例如:store.mode.
3.2client service配置
3.2.1业务数据库准备
业务库表略..
对于AT模式，必须为业务数据库分别建对应的回滚日志表，初始化此sql。seata服务器不需要它。
https://github.com/seata/seata/blob/1.3.0/script/client/at/db/mysql.sql
3.2.2业务微服务准备
POM配置
com.alibaba.cloud
spring-cloud-starter-alibaba-nacos-discovery
com.alibaba.cloud
spring-cloud-starter-alibaba-seata
seata-all
io.seata
io.seata
seata-all
1.3.0
org.springframework.cloud
spring-cloud-starter-openfeign
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-actuator
mysql
mysql-connector-java
5.1.37
com.alibaba
druid-spring-boot-starter
1.1.10
org.mybatis.spring.boot
mybatis-spring-boot-starter
2.0.0
org.springframework.boot
spring-boot-starter-test
test
org.projectlombok
lombok
true
YML配置
application.yml配置指定命名空间名称
spring:
profiles:
active: dev
bootstrap.yml 配置服务名和nacos,seata事务组
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
#配置nacos服务注册中心和配置中心
nacos:
discovery:
server-addr: 192.168.1.111:1111
group: DEV_GROUP
namespace: 300c5dc3-6326-4033-8d7e-effe12645735
config:
server-addr: 192.168.1.111:1111 #配置中心地址(nginx)
file-extension: yaml #指定yaml格式的配置
group: DEV_GROUP
namespace: 300c5dc3-6326-4033-8d7e-effe12645735
#业务配置可在nacos配置，供服务读取
# datasource:
# driver-class-name: com.mysql.jdbc.Driver
# url: jdbc:mysql://192.168.1.115:3306/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
# the client batch send request enable
enableClientBatchSendRequest = true
#thread factory for netty
threadFactory {
bossThreadPrefix = "NettyBoss"
workerThreadPrefix = "NettyServerNIOWorker"
serverExecutorThread-prefix = "NettyServerBizHandler"
shareBossWorker = false
clientSelectorThreadPrefix = "NettyClientSelector"
clientSelectorThreadSize = 1
clientWorkerThreadPrefix = "NettyClientWorkerThread"
# netty boss thread size,will not be used for UDT
bossThreadSize = 1
#auto default pin or 8
workerThreadSize = "default"
}
shutdown {
# when destroy server, wait seconds
wait = 3
}
serialization = "seata"
compressor = "none"
}
service {
#transaction service group mapping
vgroupMapping.fsp-tx-group = "default"
#only support when registry.type=file, please don't set multiple addresses
default.grouplist = "127.0.0.1:8091"
#degrade, current not support
enableDegrade = false
#disable seata
disableGlobalTransaction = false
}
client {
rm {
asyncCommitBufferLimit = 10000
lock {
retryInterval = 10
retryTimes = 30
retryPolicyBranchRollbackOnConflict = true
}
reportRetryCount = 5
tableMetaCheckEnable = false
reportSuccessEnable = false
sagaBranchRegisterEnable = false
}
tm {
commitRetryCount = 5
rollbackRetryCount = 5
degradeCheck = false
degradeCheckPeriod = 2000
degradeCheckAllowTimes = 10
}
undo {
dataValidation = true
onlyCareUpdateColumns = true
logSerialization = "jackson"
logTable = "undo_log"
}
log {
exceptionRate = 100
}
}
registry.conf
#注册中心服务发现配置nacos
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
type = "nacos"
nacos {
application = "seata-server"
serverAddr = "192.168.1.111:1111"
group = "DEV_GROUP"
namespace = "300c5dc3-6326-4033-8d7e-effe12645735"
username = "nacos"
password = "nacos"
}
eureka {
serviceUrl = "http://localhost:8761/eureka"
weight = "1"
}
redis {
serverAddr = "localhost:6379"
db = "0"
password = ""
timeout = "0"
}
zk {
serverAddr = "127.0.0.1:2181"
sessionTimeout = 6000
connectTimeout = 2000
username = ""
password = ""
}
consul {
serverAddr = "127.0.0.1:8500"
}
etcd3 {
serverAddr = "http://localhost:2379"
}
sofa {
serverAddr = "127.0.0.1:9603"
region = "DEFAULT_ZONE"
datacenter = "DefaultDataCenter"
group = "SEATA_GROUP"
addressWaitTime = "3000"
}
file {
name = "file.conf"
}
}
#配置中心使用file ，启用file.conf; 如果使用nacos 需配置相关配置
config {
# file、nacos 、apollo、zk、consul、etcd3、springCloudConfig
type = "file"
nacos {
serverAddr = "192.168.1.111:1111"
namespace = "300c5dc3-6326-4033-8d7e-effe12645735"
group = "DEV_GROUP"
username = "nacos"
password = "nacos"
}
consul {
serverAddr = "127.0.0.1:8500"
}
apollo {
appId = "seata-server"
apolloMeta = "http://192.168.1.204:8801"
namespace = "application"
}
zk {
serverAddr = "127.0.0.1:2181"
sessionTimeout = 6000
connectTimeout = 2000
username = ""
password = ""
}
etcd3 {
serverAddr = "http://localhost:2379"
}
file {
name = "file.conf"
}
}
3.2.3业务代码
略...
4.分布式事务的执行流程
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TM开启分布式事务(TM向TC注册全局事务记录)
换业务场景，编排数据库，服务等事务内资源（RM向TC汇报资源准备状态）
TM结束分布式事务，事务一阶段结束（TM通知TC提交/回滚分布式事务）
TC汇总事务信息，决定分布式事务是提交还是回滚
TC通知所有RM提交/回滚资源，事务二阶段结束。