行已被另一个事务更新或删除（或未保存值映射不正确）

我有一个在网络服务器上运行的 java 项目。我总是遇到这个例外。

我阅读了一些文档，发现悲观锁定（或乐观，但我读到悲观更好）是防止此异常的最佳方法。

但是我找不到任何清楚的例子来解释如何使用它。

我的方法是这样的：

     @Transactional
    public void test(Email email, String subject) {
        getEmailById(String id);
        email.setSubject(subject);
        updateEmail(email);
    }

尽管：

Email 是一个 Hibernate 类（它将是数据库中的一个表）
getEmailById(String id) 是一个返回 email --- 的函数（此方法未用 @Transactional 注释）
updateEmail(email) ：是一种更新电子邮件的方法。

注意： 我使用 Hibernate 进行保存、更新等操作（例如： session.getcurrentSession.save(email) ）

例外：

 ERROR 2011-12-21 15:29:24,910 Could not synchronize database state with session [myScheduler-1]
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [email#21]
    at org.hibernate.persister.entity.AbstractEntityPersister.check(AbstractEntityPersister.java:1792)
    at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2435)
    at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2335)
    at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2635)
    at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:115)
    at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:168)
    at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1027)
    at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:365)
    at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:137)
    at org.springframework.orm.hibernate3.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:656)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:754)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:723)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:393)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:120)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
    at $Proxy130.generateEmail(Unknown Source)
    at com.admtel.appserver.tasks.EmailSender.run(EmailNotificationSender.java:33)
    at com.admtel.appserver.tasks.EmailSender$$FastClassByCGLIB$$ea0d4fc2.invoke(<generated>)
    at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
    at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:688)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
    at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:55)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
    at org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor.invoke(AfterReturningAdviceInterceptor.java:50)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
    at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:50)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:621)
    at com.admtel.appserver.tasks.EmailNotificationSender$$EnhancerByCGLIB$$33eb7303.run(<generated>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.springframework.util.MethodInvoker.invoke(MethodInvoker.java:273)
    at org.springframework.scheduling.support.MethodInvokingRunnable.run(MethodInvokingRunnable.java:65)
    at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:51)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
    at java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:317)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:150)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:98)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodic(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:204)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:680)
ERROR 2011-12-21 15:29:24,915 [ exception thrown < EmailNotificationSender.run() > exception message Object of class [Email] with identifier [211]: optimistic locking failed; nested exception is org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [Email#21] with params ] [myScheduler-1]
org.springframework.orm.hibernate3.HibernateOptimisticLockingFailureException: Object of class [Email] with identifier [21]: optimistic locking failed; nested exception is

原文由 Georgian Citizen 发布，翻译遵循 CC BY-SA 4.0 许可协议

阅读 1.3k

我们有一个队列管理器，它轮询数据并将其交给处理程序进行处理。为了避免再次拾取相同的事件，队列管理器将数据库中的记录锁定为 LOCKED 状态。

     void poll() {
        record = dao.getLockedEntity();
        queue(record);
    }

此方法不是事务性的，但 dao.getLockedEntity() 是事务性的 REQUIRED 。

一切都很好，在路上，经过几个月的生产，它因乐观锁定异常而失败。

经过大量调试和详细检查后，我们发现有人更改了如下代码：

     @Transactional(propagation=Propagation.REQUIRED, readOnly=false)
    void poll() {
        record = dao.getLockedEntity();
        queue(record);
    }

因此，记录甚至在 dao.getLockedEntity() 中的事务提交之前就已排队（它使用相同的 poll 方法事务）并且对象在 poll() 时被处理程序（不同线程）在下面更改 --- 方法事务被提交。

我们解决了这个问题，现在看起来不错。我想到分享它是因为乐观锁异常可能会造成混淆并且难以调试。

原文由 Lyju I Edwinson 发布，翻译遵循 CC BY-SA 4.0 许可协议

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