mysql - Spring Data JPA 和 MySQL : How to avoid "duplicate entry" error in multithreaded environment?

Question

我的 Web 应用程序的数据库基础架构是这样分层的:

1. Spring 数据 JPA
2. JPA
3. hibernate
4. C3P0 池
5. MySQL

有些事务需要相当长的时间，有时一个大事务需要一分钟(目的是将数据缓存到数据库中):从用户到我的网络服务器的 HTTP 请求可能会开始此事务。然后，我的 Web 服务器可能会查询另一个远程第三方服务器以查找丢失的数据。收集完所有数据后，事务完成，所有收集到的数据都写入数据库。

在这个长时间运行的事务中，用户可能会重新加载我的网站。 这会导致在单独的线程中针对相同数据开始另一个事务。由于此事务的目的是缓存，因此此操作本质上是幂等的，我不介意进行相同的计算上两次。但在这些情况下，我的 Web 应用程序偶尔会遇到以下错误。

20:12:46.392 container [Thread-24] WARN  o.h.e.jdbc.spi.SqlExceptionHelper - SQL Error: 1062, SQLState: 23000
20:12:46.392 container [Thread-24] ERROR o.h.e.jdbc.spi.SqlExceptionHelper - Duplicate entry '146845042025054' for key 'PRIMARY'
20:12:46.602 container [Thread-24] INFO  o.h.e.j.b.internal.AbstractBatchImpl - HHH000010: On release of batch it still contained JDBC statements
Exception in thread "Thread-24" org.springframework.dao.DataIntegrityViolationException: Duplicate entry '146845042025054' for key 'PRIMARY'; SQL [n/a]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: Duplicate entry '146845042025054' for key 'PRIMARY'
    at org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:643)
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:104)
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:516)
    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:394)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:120)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:155)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.data.jpa.repository.support.LockModeRepositoryPostProcessor$LockModePopulatingMethodIntercceptor.invoke(LockModeRepositoryPostProcessor.java:92)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:90)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
    at com.sun.proxy.$Proxy45.save(Unknown Source)
    at com.mycompany.MyJpaEntityDomainClass.setId(MyJpaEntityDomainClass.java:83)
    at com.mycompany.MyCustomRepository.findMyJpaEntityDomainClassInstance(MyCustomRepository.java:72)
    at sun.reflect.GeneratedMethodAccessor33.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:319)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:155)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
    at com.sun.proxy.$Proxy46.findMyJpaEntityDomainClassInstance(Unknown Source)
    at com.mycompany.AnotherDomainEntityClass.setAssociatedJpaEntityDomainInstances(AnotherDomainEntityClass.java:343)
    at com.mycompany.MyThreadInvokingService$SearcherThread.run(MyThreadInvokingService.java:106)
    at java.lang.Thread.run(Thread.java:722)
Caused by: org.hibernate.exception.ConstraintViolationException: Duplicate entry '146845042025054' for key 'PRIMARY'
    at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:74)
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:129)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractProxyHandler.invoke(AbstractProxyHandler.java:81)
    at com.sun.proxy.$Proxy76.executeUpdate(Unknown Source)
    at org.hibernate.engine.jdbc.batch.internal.NonBatchingBatch.addToBatch(NonBatchingBatch.java:56)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2962)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3403)
    at org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:88)
    at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:362)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:354)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:275)
    at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:326)
    at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:52)
    at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1210)
    at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:399)
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.beforeTransactionCommit(JdbcTransaction.java:101)
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.commit(AbstractTransactionImpl.java:175)
    at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:75)
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:512)
    ... 31 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '146845042025054' for key 'PRIMARY'
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.Util.getInstance(Util.java:386)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1040)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4074)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4006)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2468)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2629)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2719)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2450)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2371)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2355)
    at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeUpdate(NewProxyPreparedStatement.java:105)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:122)
    ... 48 more

调用com.sun.proxy.$Proxy45.save实际上是对 save 的调用MyJpaEntityDomainClassRepository extends org.springframework.data.jpa.repository.JpaRepository<MyJpaEntityDomainClass, String>的方法| .

正如您可以从此堆栈跟踪中推断的那样，MyJpaEntityDomainClass实例负责在存储库中创建和更新自身。

我感觉 重复输入错误 发生在两个并发线程试图将同一个实体写入数据库的情况下。我根本不明白为什么会发生此错误，因为 org.springframework.data.jpa.repository.JpaRepositor.save( uniqueId )在稍后的线程中应该只覆盖 uniqueId -相关的实体/记录由稍早的线程放入存储库。

如何避免此类与交易相关的重复输入竞争条件错误？

Answer 1

当尝试插入同一实体的两个记录时，将发生重复输入错误。要检查的事情是:

• 是跨线程共享的同一个 JPA/Hibernate session 错误时更新。
• 如何生成唯一的记录 ID？ ( myqsl自动递增 ; id 生成器代码。等)，如果有一个 id列是否与实际主键(约束)不同 table 的。