Common scenarios in which Seata distributed transactions fail and do not take effect (transactions do not rollback)

One 、 Microservices are not normally obtained XID

Check the method ：

Call methods in every microservice RootContext.getXID() Check XID

for example , service A Service called B And the service C

Then we can respectively serve A、 service B、 service C Add in the transaction method of

=============== service A
@Service
public class ServiceAImpl implements IServiceA
{

    private static final Logger log = LoggerFactory.getLogger(ServiceAImpl.class);

    @Autowired
    private IServiceB serviceB;
    @Autowired
    private IServiceC serviceC;
    
    @Override
    @GlobalTransactional
    @Transactional
    public Boolean doA() {
        log.info("Seata Global transaction id=================>{}",RootContext.getXID());
        //......
    }

}

=============== service B
@Service
public class ServiceBImpl implements IServiceB
{

    private static final Logger log = LoggerFactory.getLogger(ServiceBImpl.class);

    @Override
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public Boolean doB() {
        log.info("Seata Global transaction id=================>{}",RootContext.getXID());
        //......
    }

}

=============== service C
@Service
public class ServiceCImpl implements IServiceC
{

    private static final Logger log = LoggerFactory.getLogger(ServiceCImpl.class);

    @Override
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public Boolean doC() {
        log.info("Seata Global transaction id=================>{}",RootContext.getXID());
        //......
    }

}

（1） see XID Is it null

（2） In every service XID atypism

If there is one of the above two , It's basically because XID Cause the transaction to fail

terms of settlement :

（1）XID Normally, it is passed to the downstream service through the parameters on the request header , Can pass seta Bag getModifyRequest Under the method headers.put Break points for analysis

（2） Directly pass parameters to downstream services in the calling method

=============== service A
@Service
public class ServiceAImpl implements IServiceA
{

    private static final Logger log = LoggerFactory.getLogger(ServiceAImpl.class);

    @Autowired
    private IServiceB serviceB;
    @Autowired
    private IServiceC serviceC;
    
    @Override
    @GlobalTransactional
    @Transactional
    public Boolean doA() {
        String XID = RootContext.getXID();
        serviceB.doB(XID);
        serviceC.doC(XID);
        //......
    }

}

=============== service B
@Service
public class ServiceBImpl implements IServiceB
{

    private static final Logger log = LoggerFactory.getLogger(ServiceBImpl.class);

    @Override
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public Boolean doB(XID) {
        RootContext.bind(XID);
        //......
    }

}

=============== service C
@Service
public class ServiceCImpl implements IServiceC
{

    private static final Logger log = LoggerFactory.getLogger(ServiceCImpl.class);

    @Override
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public Boolean doC(XID) {
        RootContext.bind(XID);
        //......
    }

}

Two 、undo_log Dirty data in the table

When Seata There is no normal end , Each service corresponds to undo_log Table and seata Persistent database brach_table、global_table、lock_table、undo_log There may be dirty data in the table that is not deleted correctly , This causes the service to rollback all the time , But it didn't succeed

** terms of settlement :** eliminate undo_log Tables and seata Persistent database brach_table、global_table、lock_table、undo_log Dirty data in the table

3、 ... and 、Fegin The call uses Fallback Degraded or thrown exceptions are handled globally

In this case, it belongs to seata The service cannot find the exception thrown by the downstream service , The transaction will not trigger rollback

terms of settlement :

（1） adopt GlobalTransactionContext.reload(RootContext.getXID()).rollback() Do a manual rollback

=============== service A
@Service
public class ServiceAImpl implements IServiceA
{

    private static final Logger log = LoggerFactory.getLogger(ServiceAImpl.class);

    @Autowired
    private IServiceB serviceB;
    @Autowired
    private IServiceC serviceC;
    
    @Override
    @GlobalTransactional
    @Transactional
    public Boolean doA() {
        Integer bStatus = serviceB.doB();
        if(bStatus == 0){// stay Mybatis in , The return value is 0 Prove that the insertion failed 
            // Manual rollback 
            GlobalTransactionContext.reload(RootContext.getXID()).rollback();
            return false;
        }
        Integer cStatus = serviceC.doC();
        if(cStatus == 0){// stay Mybatis in , The return value is 0 Prove that the insertion failed 
            // Manual rollback 
            GlobalTransactionContext.reload(RootContext.getXID()).rollback();
            return false;
        }
        //......
    }

}

=============== service B
@Service
public class ServiceBImpl implements IServiceB
{

    private static final Logger log = LoggerFactory.getLogger(ServiceBImpl.class);

    @Override
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public Boolean doB() {
        //......
        Integer insertStatus = serviceBDAO.insert();
        return insertStatus;
    }

}

=============== service C
@Service
public class ServiceCImpl implements IServiceC
{

    private static final Logger log = LoggerFactory.getLogger(ServiceCImpl.class);

    @Override
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public Boolean doC() {
        //......
        Integer insertStatus = serviceCDAO.insert();
        return insertStatus;
    }

}

（2） Through cut class

See official documents for details

https://gitee.com/link?target=http%3A%2F%2Fseata.io%2Fzh-cn%2Fblog%2Fseata-spring-boot-aop-aspectj.html