seata 1.5.2分布式事务之at -凯发k8国际

1.seata-server1.5.2下载
https://seata.io/zh-cn/blog/download.html
在你的mysql数据库中创建名为seata的库
/script/server/db/mysql.sql

2.在你的参与全局事务的数据库中加入undo_log这张表
create table if not exists `undo_log`
(
    `branch_id`     bigint(20)   not null comment 'branch transaction id',
    `xid`           varchar(100) not null comment 'global transaction id',
    `context`       varchar(128) 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 key `ux_undo_log` (`xid`, `branch_id`)
) engine = innodb
  auto_increment = 1
  default charset = utf8 comment ='at transaction mode undo table';

3.在你的项目中引入seata依赖


            io.seata
            seata-spring-boot-starter
           
               
                    com.alibaba
                    druid
               
           
       
       
            com.alibaba.cloud
            spring-cloud-starter-alibaba-seata
           
               
                    io.seata
                    seata-spring-boot-starter
               
           
       

4.application.yml
seata:
   enabled: true
   application-id: orders-service
   tx-service-group: default-tx-group
   config:
      type: nacos
      nacos:
         namespace: 0ef84c31-0570-4591-a708-1945a253048d
         serveraddr: 127.0.0.1:8848
         group: seata_group
         username: "nacos"
         password: "nacos"
         data-id: seataserver.properties
   registry:
      type: nacos
      nacos:
         application: seata-server
         serveraddr: 127.0.0.1:8848
         group: seata_group
         namespace: 0ef84c31-0570-4591-a708-1945a253048d
         username: "nacos"
         password: "nacos"
   data-source-proxy-mode: at

5.运行你下载的nacos,并参考https://github.com/seata/seata/tree/develop/script/config-center 的config.txt并修改

命名空间：seata_group
dataid: service.vgroupmapping.default-tx-group
dataid: seataserver.properties

service.vgroupmapping.default-tx-groupneirong内容：
default

seataserver.propertiesneirong内容如下：
transport.type=tcp
transport.server=nio
transport.heartbeat=true
transport.enabletmclientbatchsendrequest=false
transport.enablermclientbatchsendrequest=true
transport.enabletcserverbatchsendresponse=false
transport.rpcrmrequesttimeout=30000
transport.rpctmrequesttimeout=30000
transport.rpctcrequesttimeout=30000
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
transport.serialization=seata
transport.compressor=none

#transaction routing rules configuration, only for the client
service.vgroupmapping.default-tx-group=default
#if you use a registry, you can ignore it
service.default.grouplist=127.0.0.1:8091
service.enabledegrade=false
service.disableglobaltransaction=false

#transaction rule configuration, only for the client
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=true
client.rm.tablemetacheckerinterval=60000
client.rm.sqlparsertype=druid
client.rm.reportsuccessenable=false
client.rm.sagabranchregisterenable=false
client.rm.sagajsonparser=fastjson
client.rm.tccactioninterceptororder=-2147482648
client.tm.commitretrycount=5
client.tm.rollbackretrycount=5
client.tm.defaultglobaltransactiontimeout=60000
client.tm.degradecheck=false
client.tm.degradecheckallowtimes=10
client.tm.degradecheckperiod=2000
client.tm.interceptororder=-2147482648
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.undo.compress.enable=true
client.undo.compress.type=zip
client.undo.compress.threshold=64k
#for tcc transaction mode
tcc.fence.logtablename=tcc_fence_log
tcc.fence.cleanperiod=1h

#log rule configuration, for client and server
log.exceptionrate=100

#transaction storage configuration, only for the server. the file, db, and redis configuration values are optional.
store.mode=db
store.lock.mode=db
store.session.mode=db
#used for password encryption
store.publickey=

#if `store.mode,store.lock.mode,store.session.mode` are not equal to `file`, you can remove the configuration block.
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

#these configurations are required if the `store mode` is `db`. if `store.mode,store.lock.mode,store.session.mode` are not equal to `db`, you can remove the configuration block.

#连接数据库要修改
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
store.db.user=abc
store.db.password=1000
store.db.minconn=5
store.db.maxconn=30
store.db.globaltable=global_table
store.db.branchtable=branch_table
store.db.distributedlocktable=distributed_lock
store.db.querylimit=100
store.db.locktable=lock_table
store.db.maxwait=5000

#these configurations are required if the `store mode` is `redis`. if `store.mode,store.lock.mode,store.session.mode` are not equal to `redis`, you can remove the configuration block.
store.redis.mode=single
store.redis.single.host=127.0.0.1
store.redis.single.port=6379
store.redis.sentinel.mastername=
store.redis.sentinel.sentinelhosts=
store.redis.maxconn=10
store.redis.minconn=1
store.redis.maxtotal=100
store.redis.database=0
store.redis.password=
store.redis.querylimit=100

#transaction rule configuration, only for the server
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
server.distributedlockexpiretime=10000
server.xaernotaretrytimeout=60000
server.session.branchasyncqueuesize=5000
server.session.enablebranchasyncremove=false
server.enableparallelrequesthandle=false

#metrics configuration, only for the server
metrics.enabled=false
metrics.registrytype=compact
metrics.exporterlist=prometheus
metrics.exporterprometheusport=9898

6.在全局事务调用者(发起全局事务的服务)的接口上加入@globaltransactional
    @requestmapping("/save")
    @globaltransactional(lockretryinternal = 10,lockretrytimes = 30)
    public boolean save(@requestbody orders orders) {
        return ordersservice.save(orders);
    }


7.其它知识：
执行阶段：
- 可回滚：根据 sql 解析结果，记录回滚日志
- 持久化：回滚日志和业务 sql 在同一个本地事务中提交到数据库
完成阶段：
- 分支提交：异步删除回滚日志记录
- 分支回滚：依据回滚日志进行反向补偿更新
其实xa流程相对at模式,是简单许多
at: 解析sql生成undolog 竞争全局锁(rpc)