我通过在Spring Batch期间手动查杀并重新启动PostGreSQL数据库来重现连接问题。我一直在使用DriverManagerDataSource，它刚刚崩溃，所以我不得不改变。现在我正在尝试使用C3P0（使用Hibernate）。
帖子很长，但主要是配置文件或堆栈跟踪，你不一定需要阅读。
我的主要问题是（我认为）：c3p0关闭连接，然后Sping-JTA尝试回滚它，并且失败，这会导致批处理。我不知道如何防止它。
我正在使用Spring，Spring批处理（4.2.3），hibernate（4.3.6）和c3p0（0.9.5.2）以及postgresql。
applicationContext：
<bean id="jpaVendorAdapter"
class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="database" value="POSTGRESQL" />
<property name="databasePlatform" value="org.hibernate.dialect.PostgreSQLDialect" />
<property name="generateDdl" value="false" />
<property name="showSql" value="false" />
</bean>
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceXmlLocation" value="classpath:META-INF/persistence.xml" />
<property name="persistenceUnitName" value="ASO_PU" />
<property name="jpaVendorAdapter" ref="jpaVendorAdapter" />
</bean>
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
persitence.xml
<persistence-unit name="ASO_PU" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class> ** my entities </class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect"/>
<property name="hibernate.connection.driver_class" value="org.postgresql.Driver" />
<property name="hibernate.connection.username" value="postgres" />
<property name="hibernate.connection.password" value="postgres" />
<property name="hibernate.connection.url" value="jdbc:postgresql://localhost:5434/aso_test" />
<property name="hibernate.connection.provider_class" value="org.hibernate.connection.C3P0ConnectionProvider"/>
<property name="hibernate.c3p0.maxSize" value="6"/> <!-- maxPoolSize -->
<property name="hibernate.c3p0.minSize" value="2"/> <!-- minPoolSize -->
<property name="hibernate.c3p0.maxStatements" value="30"/> <!-- maxStatements -->
<property name="hibernate.c3p0.validate" value="true"/> <!-- testConnectionOnCheckout -->
<property name="hibernate.c3p0.preferredTestQuery" value="SELECT 1"/> <!-- -->
<property name="hibernate.c3p0.acquireRetryAttempts" value="121"/>
<property name="hibernate.c3p0.acquireRetryDelay" value="2002"/>
</properties>
</persistence-unit>
当我杀死它后应用程序尝试连接到数据库时，它会警告我，然后等待直到数据库再次启动（我不认为它是相关的，但无论如何这里是跟踪：）
ATTENTION: [c3p0] A PooledConnection that has already signalled a Connection error is still in use!
31 août 2016 11:44:54 com.mchange.v2.c3p0.impl.NewPooledConnection handleThrowable
ATTENTION: [c3p0] Another error has occurred [ org.postgresql.util.PSQLException: This connection has been closed. ] which will not be reported to listeners!
org.postgresql.util.PSQLException: This connection has been closed.
at org.postgresql.jdbc2.AbstractJdbc2Connection.checkClosed(AbstractJdbc2Connection.java:837)
at org.postgresql.jdbc2.AbstractJdbc2Connection.rollback(AbstractJdbc2Connection.java:854)
at com.mchange.v2.c3p0.impl.NewProxyConnection.rollback(NewProxyConnection.java:860)
at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doRollback(JdbcTransaction.java:163)
at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.rollback(AbstractTransactionImpl.java:211)
at org.hibernate.jpa.internal.TransactionImpl.rollback(TransactionImpl.java:108)
at org.springframework.orm.jpa.JpaTransactionManager.doRollback(JpaTransactionManager.java:544)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processRollback(AbstractPlatformTransactionManager.java:853)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.rollback(AbstractPlatformTransactionManager.java:830)
at org.springframework.transaction.support.TransactionTemplate.rollbackOnException(TransactionTemplate.java:164)
at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:137)
at org.springframework.batch.core.step.tasklet.TaskletStep$2.doInChunkContext(TaskletStep.java:271)
at org.springframework.batch.core.scope.context.StepContextRepeatCallback.doInIteration(StepContextRepeatCallback.java:77)
at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:368)
at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215)
at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:144)
at org.springframework.batch.core.step.tasklet.TaskletStep.doExecute(TaskletStep.java:257)
at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:198)
at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:148)
at org.springframework.batch.core.job.flow.JobFlowExecutor.executeStep(JobFlowExecutor.java:64)
at org.springframework.batch.core.job.flow.support.state.StepState.handle(StepState.java:67)
at org.springframework.batch.core.job.flow.support.SimpleFlow.resume(SimpleFlow.java:165)
at org.springframework.batch.core.job.flow.support.SimpleFlow.start(SimpleFlow.java:144)
at org.springframework.batch.core.job.flow.FlowJob.doExecute(FlowJob.java:134)
at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:304)
at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:135)
at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50)
at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:128)
at fr.aso.batch.test.MyBatchTest.test(MyBatchTest.java:100)
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.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:254)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
31 août 2016 11:44:54 com.mchange.v2.c3p0.impl.NewPooledConnection handleThrowable
ATTENTION: [c3p0] A PooledConnection that has already signalled a Connection error is still in use!
在此异常之后，批处理挂起。一旦DB再次启动（1分钟后），整个批次崩溃：
01/09/2016 09:22:47.537 [ERROR] REI - org.springframework.batch.core.job.AbstractJob Exception encountered in afterStep callback
org.springframework.transaction.TransactionSystemException: Could not roll back JPA transaction; nested exception is javax.persistence.PersistenceException: unexpected error when rollbacking
at org.springframework.orm.jpa.JpaTransactionManager.doRollback(JpaTransactionManager.java:548) ~[spring-orm-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processRollback(AbstractPlatformTransactionManager.java:853) ~[spring-tx-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.rollback(AbstractPlatformTransactionManager.java:830) ~[spring-tx-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.completeTransactionAfterThrowing(TransactionAspectSupport.java:503) ~[spring-tx-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:285) ~[spring-tx-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) ~[spring-tx-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208) ~[spring-aop-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at $Proxy204.afterJob(Unknown Source) ~[na:na]
at org.springframework.batch.core.listener.CompositeJobExecutionListener.afterJob(CompositeJobExecutionListener.java:60) ~[spring-batch-core-3.0.4.RELEASE.jar:3.0.4.RELEASE]
at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:346) ~[spring-batch-core-3.0.4.RELEASE.jar:3.0.4.RELEASE]
at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:135) [spring-batch-core-3.0.4.RELEASE.jar:3.0.4.RELEASE]
at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50) [spring-core-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:128) [spring-batch-core-3.0.4.RELEASE.jar:3.0.4.RELEASE]
at fr.aso.batch.OpsTest.testRecuperationEtabsEmployantSalariesCNAMJob(OpsTest.java:100) [test-classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.6.0_30]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) ~[na:1.6.0_30]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) ~[na:1.6.0_30]
at java.lang.reflect.Method.invoke(Method.java:597) ~[na:1.6.0_30]
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) [junit-4.12.jar:4.12]
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) [junit-4.12.jar:4.12]
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) [junit-4.12.jar:4.12]
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75) [spring-test-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86) [spring-test-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84) [spring-test-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) [junit-4.12.jar:4.12]
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:254) [spring-test-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89) [spring-test-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) [spring-test-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) [spring-test-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193) [spring-test-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) [.cp/:na]
Caused by: javax.persistence.PersistenceException: unexpected error when rollbacking
at org.hibernate.jpa.internal.TransactionImpl.rollback(TransactionImpl.java:111) ~[hibernate-entitymanager-4.3.5.Final.jar:4.3.5.Final]
at org.springframework.orm.jpa.JpaTransactionManager.doRollback(JpaTransactionManager.java:544) ~[spring-orm-4.2.3.RELEASE.jar:4.2.3.RELEASE]
... 43 common frames omitted
Caused by: org.hibernate.TransactionException: rollback failed
at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.rollback(AbstractTransactionImpl.java:217) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
at org.hibernate.jpa.internal.TransactionImpl.rollback(TransactionImpl.java:108) ~[hibernate-entitymanager-4.3.5.Final.jar:4.3.5.Final]
... 44 common frames omitted
Caused by: org.hibernate.TransactionException: unable to rollback against JDBC connection
at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doRollback(JdbcTransaction.java:167) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.rollback(AbstractTransactionImpl.java:211) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
... 45 common frames omitted
Caused by: org.postgresql.util.PSQLException: This connection has been closed.
at org.postgresql.jdbc2.AbstractJdbc2Connection.checkClosed(AbstractJdbc2Connection.java:837) ~[postgresql-9.3-1101.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Connection.rollback(AbstractJdbc2Connection.java:854) ~[postgresql-9.3-1101.jdbc4.jar:na]
at com.mchange.v2.c3p0.impl.NewProxyConnection.rollback(NewProxyConnection.java:860) ~[c3p0-0.9.2.1.jar:0.9.2.1]
at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doRollback(JdbcTransaction.java:163) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
... 46 common frames omitted
从这个堆栈跟踪判断，我认为它是这样的：当数据库死亡时c3p0关闭了连接，当JTA试图回滚时，c3p0挂起，直到DB再次活着。一旦它再次启动，回滚可能会启动，但它会尝试在已关闭的连接上回滚，因此异常会终止整个批处理。
我认为当连接关闭时，c3p0会得到一个新的，但我想这在回滚时是不可能的（它会在之后尝试？），并且Spring JTA必须尝试回滚才能尝试重新连接。
首先，我不知道我所说的是否正确...... JTA是否可能尝试回滚已关闭的交易？
如果是这样，我没有找到任何关于如何处理JTA回滚期间的问题，或者可能是c3p0？冬眠？甚至是Spring批次？
我该怎么办？ （要么确定问题是什么或如何解决它）。
任何帮助表示赞赏。提前谢谢（这是一个很长的帖子......）
崩溃可能随时发生，因为当我杀死数据库时，它发生在处理器上。但是我也可以在spring批量更新其job_instance_execution表时，或者每当，但我认为它全部由spring-JTA / hibernate / c3p0管理，所以我正在看这个而不是弹簧批。
答案 0 :(得分：2)
除非您使用的是正式的分布式事务（即XAConnection），否则强制执行JDBC事务的级别是Connection对象。如果一个Connection因未提交的事务工作而死亡，那么该工作将会丢失。没有什么可以做的。如果您想要在Connection断开的情况下提交部分工作，请以更细粒度的方式定义您的事务，以便立即提交您想要提交的工作。
除非您设置了c3p0.unreturnedConnectionTimeout（不是您的问题），否则c3p0永远不会close()从应用程序下面连接。 c3p0正在报告来自Postgres的错误，该错误已经注意到底层连接已经关闭。在您的应用程序（直接或通过休眠）调用Connection上的close()之前，无论它多么破碎，都会结帐。
在你描述的所有内容中，唯一不寻常的是在第二次投诉之前暂停。可能的顺序是：
close()以返回它以控制连接池步骤5和6的顺序有点令人惊讶。从概念上讲，没有理由说JPA无法立即向应用程序报告失败。除此之外，一切都应该如此。
“我该怎么办？”
确保编写应用程序以使其了解可能发生JPA故障，并确保应用程序始终处于一致状态。如果发生故障，您的应用程序可能会重试失败的工作，或者它可能只是向客户端报告失败（无论是最终用户是通过某种消息，还是通过异常报告给其他软件）。如果即使在重试之后故障仍然存在，最终您可能必须报告故障（除非有某种方法可以解决并从没有数据库的故障中恢复，这是不可能的）。应用程序无法确保整个网络中的数据库不会消失。
在c3p0级别，如果您希望可以设置testConnectionOnCheckin和idleConnectionTestPeriod，以确保在数据库丢失频繁时立即清除错误的连接。 （就正确性而言，使用testConnectionOnCheckout通过hibernate.c3p0.validate的当前设置是正常的，但它会导致池懒惰地替换Connections，因为客户端要求它们。有关连接测试文档，请参阅here和here。