JPA 并发事务

【问题标题】：JPA concurrent transactionsJPA 并发事务
【发布时间】：2011-07-05 14:29:03
【问题描述】：

我在使用 JPA-1.0、Hibernate 和 MySQL 5.0.84（innoDB 表）以及 Postgres 8.1.11（不同客户端的不同数据库）的并发事务方面遇到问题。我不知道我是否遗漏了有关配置的内容，因为我已经阅读了有关 JPA 事务的规范，并且根据我遇到的问题， 我需要为事务注释指定一个特定的隔离级别。我这样做了，但它只是一起关闭了事务，所以没有任何东西被持久化/更新。

我正在做的是，向网络服务器（在我的例子中是 tomcat）发起 http 帖子，然后在 http 请求进入时尝试生成多个数据库事务。 每个事务包括 1 个插入和 2 个更新。不过，问题似乎总是出现在最终更新上，这是基于之前的插入。 所以，我插入记录 A，然后更新记录 B，它是记录 A 的外键。

以下是我在执行单个 http 请求时获得的日志记录：


org.springframework.orm.jpa.JpaTransactionManager:365 - Creating new transaction with name [biz.cytrus.overlord.v2.core.ExecutionLogAPI.create]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT; ''
org.springframework.orm.jpa.JpaTransactionManager:323 - Opened new EntityManager [org.hibernate.ejb.EntityManagerImpl@221f81] for JPA transaction
org.springframework.orm.jpa.JpaTransactionManager:355 - Exposing JPA transaction as JDBC transaction [org.springframework.orm.jpa.vendor.HibernateJpaDialect$HibernateConnectionHandle@9f5742]
org.springframework.orm.jpa.JpaTransactionManager:752 - Initiating transaction commit
org.springframework.orm.jpa.JpaTransactionManager:462 - Committing JPA transaction on EntityManager [org.hibernate.ejb.EntityManagerImpl@221f81]
org.springframework.orm.jpa.JpaTransactionManager:548 - Closing JPA EntityManager [org.hibernate.ejb.EntityManagerImpl@221f81] after transaction
org.springframework.orm.jpa.EntityManagerFactoryUtils:329 - Closing JPA EntityManager

以下是我同时执行多个http请求时得到的日志：


org.hibernate.util.JDBCExceptionReporter:357 - SQL Error: 1213, SQLState: 40001
org.hibernate.util.JDBCExceptionReporter:454 - Deadlock found when trying to get lock; try restarting transaction
org.hibernate.event.def.AbstractFlushingEventListener:532 - Could not synchronize database state with session
org.hibernate.exception.LockAcquisitionException: Could not execute JDBC batch update
        at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:105)
        at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
        at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275)
        at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:266)
        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.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:54)
        at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:467)
        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:375)
        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 $Proxy66.create(Unknown Source)
        at biz.cytrus.overlord.v2.web.action.task.LogAction.createLogEntry(LogAction.java:84)
        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:592)
        at net.sourceforge.stripes.controller.DispatcherHelper$6.intercept(DispatcherHelper.java:442)
        at net.sourceforge.stripes.controller.ExecutionContext.proceed(ExecutionContext.java:158)
        at net.sourceforge.stripes.controller.BeforeAfterMethodInterceptor.intercept(BeforeAfterMethodInterceptor.java:113)
        at net.sourceforge.stripes.controller.ExecutionContext.proceed(ExecutionContext.java:155)
        at net.sourceforge.stripes.controller.ExecutionContext.wrap(ExecutionContext.java:74)
        at net.sourceforge.stripes.controller.DispatcherHelper.invokeEventHandler(DispatcherHelper.java:440)
        at net.sourceforge.stripes.controller.DispatcherServlet.invokeEventHandler(DispatcherServlet.java:278)
        at net.sourceforge.stripes.controller.DispatcherServlet.service(DispatcherServlet.java:160)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at net.sourceforge.stripes.controller.StripesFilter.doFilter(StripesFilter.java:247)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
        at java.lang.Thread.run(Thread.java:595)
Caused by: java.sql.BatchUpdateException: Deadlock found when trying to get lock; try restarting transaction
        at com.mysql.jdbc.ServerPreparedStatement.executeBatch(ServerPreparedStatement.java:657)
        at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeBatch(NewProxyPreparedStatement.java:1723)
        at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:70)
        at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:268)
        ... 48 more
org.springframework.orm.jpa.JpaTransactionManager:893 - Initiating transaction rollback after commit exception
org.springframework.dao.CannotAcquireLockException: Could not execute JDBC batch update; SQL [update application_instances set application_id=?, create_date=?, for_ongoing_task=?, last_log_id=?, last_notified_date=?, name=?, param_string=?, application_status_id=?, status_date=? where id=?]; nested exception is org.hibernate.exception.LockAcquisitionException: Could not execute JDBC batch update
        at org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:633)
        at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:97)
        at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:471)
        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:375)
        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 $Proxy66.create(Unknown Source)
        at biz.cytrus.overlord.v2.web.action.task.LogAction.createLogEntry(LogAction.java:84)
        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:592)
        at net.sourceforge.stripes.controller.DispatcherHelper$6.intercept(DispatcherHelper.java:442)
        at net.sourceforge.stripes.controller.ExecutionContext.proceed(ExecutionContext.java:158)
        at net.sourceforge.stripes.controller.BeforeAfterMethodInterceptor.intercept(BeforeAfterMethodInterceptor.java:113)
        at net.sourceforge.stripes.controller.ExecutionContext.proceed(ExecutionContext.java:155)
        at net.sourceforge.stripes.controller.ExecutionContext.wrap(ExecutionContext.java:74)
        at net.sourceforge.stripes.controller.DispatcherHelper.invokeEventHandler(DispatcherHelper.java:440)
        at net.sourceforge.stripes.controller.DispatcherServlet.invokeEventHandler(DispatcherServlet.java:278)
        at net.sourceforge.stripes.controller.DispatcherServlet.service(DispatcherServlet.java:160)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at net.sourceforge.stripes.controller.StripesFilter.doFilter(StripesFilter.java:247)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
        at java.lang.Thread.run(Thread.java:595)
Caused by: org.hibernate.exception.LockAcquisitionException: Could not execute JDBC batch update
        at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:105)
        at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
        at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275)
        at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:266)
        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.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:54)
        at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:467)
        ... 39 more
Caused by: java.sql.BatchUpdateException: Deadlock found when trying to get lock; try restarting transaction
        at com.mysql.jdbc.ServerPreparedStatement.executeBatch(ServerPreparedStatement.java:657)
        at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeBatch(NewProxyPreparedStatement.java:1723)
        at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:70)
        at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:268)
        ... 48 more
org.springframework.orm.jpa.JpaTransactionManager:488 - Rolling back JPA transaction on EntityManager [org.hibernate.ejb.EntityManagerImpl@7ca9bd]
org.springframework.orm.jpa.JpaTransactionManager:548 - Closing JPA EntityManager [org.hibernate.ejb.EntityManagerImpl@7ca9bd] after transaction
org.springframework.orm.jpa.EntityManagerFactoryUtils:329 - Closing JPA EntityManager

在尝试解决此问题时，我尝试在事务注释上设置隔离级别，但这会导致数据库上没有任何活动：


org.springframework.orm.jpa.JpaTransactionManager:365 - Creating new transaction with name [biz.cytrus.overlord.v2.core.ExecutionLogAPI.create]: PROPAGATION_REQUIRED,ISOLATION_REPEATABLE_READ; ''
org.springframework.orm.jpa.JpaTransactionManager:323 - Opened new EntityManager [org.hibernate.ejb.EntityManagerImpl@adddd6] for JPA transaction
org.springframework.orm.jpa.EntityManagerFactoryUtils:329 - Closing JPA EntityManager

非常感谢任何有关如何解决此问题的帮助。

这是标有@Transactional注解的方法中代码的sn-p：


Task task = ongoingTaskAPI.findById(taskId);
ExecutionLog executionLog = new ExecutionLog();
executionLog.setStatusDate(new Date());
executionLog.setStatus(status);

        executionLog.setApplicationInstance(task.getApplicationInstance());

executionLog.getApplicationInstance().setLastLog(executionLog);
em.persist(executionLog);

实体bean的相关部分如下：


public class ExecutionLog implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;

    @ManyToOne
    @JoinColumn(name="application_instance_id")
    private ApplicationInstance applicationInstance;


public class ApplicationInstance implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;

    @OneToOne
    @JoinColumn(name="last_log_id", nullable = true)
    private ExecutionLog lastLog;

在任何时候都存在一对一的关系，特定的日志记录只能链接到特定的应用程序实例记录。

所以本质上，我所做的是创建日志记录，然后更新应用程序实例，使其链接到与其相关的最新日志记录。这是在单个事务方法中完成的，但是在更新应用程序实例记录时似乎会发生故障。但是，这在单个调用上运行良好，但在并发调用上却不行。

希望这能让我的问题更加清晰。

【问题讨论】：

  • 我在上面添加了一个代码sn-p。根据堆栈跟踪，BatchUpdateException 发生在 em.persist 之前的行上，该行在应用程序实例上设置日志记录。

标签： java mysql postgresql jpa transactions


【解决方案1】：

指向最新日志条目的共享“应用程序实例”行正在请求锁定问题。在我看来，顺序将是：

  • 从 application_instance 中选择
  • 插入 execution_log，引用 application_instance（在 application_instance 行上获取共享锁）
  • 更新 application_instance（对 application_instance 行进行排他锁定）

所以两个线程都可以在 application_instance 上拥有共享锁；然后线程 A 阻塞线程 B 试图进行更新，然后线程 B 阻塞线程 A...

我会通过立即获得具有独占锁的应用程序实例来解决这个问题。在直接的 Hibernate 术语中，通过在加载实体（session.get 或查询）时指定 LockMode.UPGRADE（或 LockMode.PESSIMISTIC_WRITE）来完成。

（我还会重新检查您是否真的需要更新 application_instance 以每次都指向最新的日志条目 - 这是一个瓶颈，因为所有事务都需要对其进行同步/序列化。）

【讨论】：

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