生产级踩坑实录：Seata AT模式悬挂、空回滚与全局锁死锁调优实战

TRANSACTION 1: 持有 t_order 的 RECORD LOCK，等待 Seata global_lock 表锁
TRANSACTION 2: 持有 Seata global_lock 表锁，等待 t_order 的 RECORD LOCK

@Service
public class OrderService {

    // 正确姿势：全局事务注解只包裹业务编排，本地事务只针对单表insert
    @GlobalTransactional(timeoutMills = 300000, name = "create-order")
    public void createOrder(OrderDTO dto) {
        // 1. 本地事务单独控制（使用编程式事务或脱离大事务）
        orderDao.insert(order); 
        
        // 2. 远程调用（剥离出Spring事务上下文）
        storageFeign.decrease(dto.getProductId());
        accountFeign.decrease(dto.getUserId());
    }
}

@Slf4j
@Component
public class StorageTccActionImpl implements StorageTccAction {

    @Autowired
    private FreezeMapper freezeMapper;

    @Override
    @TwoPhaseBusinessAction(name = "deductStorage", commitMethod = "commit", rollbackMethod = "rollback")
    public boolean tryDecuct(BusinessActionContext context, Long productId, Integer count) {
        // 1. 【防悬挂校验】先检查是否已经有该事务ID的Cancel日志
        String xid = context.getXid();
        if (freezeMapper.existsCancelLog(xid)) {
            log.warn("检测到Cancel已提前执行，拒绝本次Try，防止悬挂。Xid: {}", xid);
            return false; // 直接返回，不预留资源
        }
        
        // 2. 【幂等校验】检查是否已Try过
        if (freezeMapper.existsTryLog(xid)) {
            log.info("Try已执行过，幂等返回。Xid: {}", xid);
            return true;
        }

        // 3. 核心业务：扣减可用库存，增加冻结库存
        storageMapper.decreaseAvailable(productId, count);
        FreezeRecord record = new FreezeRecord();
        record.setXid(xid);
        record.setProductId(productId);
        record.setCount(count);
        freezeMapper.insert(record); // 记录Try日志
        
        // 4. 将上下文参数存入context，供Commit/Cancel使用
        context.getActionContext().put("productId", productId);
        context.getActionContext().put("count", count);
        return true;
    }

    @Override
    public boolean commit(BusinessActionContext context) {
        // 幂等提交：删除冻结记录，实际扣减已在Try中完成
        return freezeMapper.deleteByXid(context.getXid()) > 0;
    }

    @Override
    public boolean rollback(BusinessActionContext context) {
        // 【防空回滚】若没有Try日志，则不执行任何业务回滚
        if (!freezeMapper.existsTryLog(context.getXid())) {
            log.warn("空回滚检测，无Try记录，直接返回成功。Xid: {}", context.getXid());
            return true;
        }
        // 释放冻结库存，增加可用库存
        FreezeRecord record = freezeMapper.selectByXid(context.getXid());
        storageMapper.increaseAvailable(record.getProductId(), record.getCount());
        return freezeMapper.deleteByXid(context.getXid()) > 0;
    }
}

{
  "name": "orderPostProcess",
  "states": [
    {
      "name": "callErp",
      "type": "serviceTask",
      "serviceName": "erpFacade",
      "serviceMethod": "syncOrder",
      "timeout": 3000, 
      "compensateState": "erpCompensate"
    }
  ]
}