java - 通讯链路故障 : Connection reset with C3P0

Question

我知道这个问题已经被问过很多次了，但我坚持不下去了。

我验证了以下内容:

IP address or hostname in JDBC URL is correct.

Hostname in JDBC URL is also recognized by local DNS server.

Port number is correct in JDBC URL.

DB server is up.

由于有时会出现相同的数据库调用，我认为这与“连接中断”有关。在问题发生时，我们只有 50-60 个连接 到数据库。

不过，我相信 C3PO 连接 可能已经耗尽。

我们有以下 C3P0 配置

<props>
<prop key="hibernate.c3p0.timeout">
44000
<!--  seconds  -->
</prop>
<prop key="hibernate.c3p0.min_size">5</prop>
<prop key="hibernate.c3p0.max_size">5</prop>
<prop key="hibernate.c3p0.initial_pool_size">5</prop>
<prop key="hibernate.c3p0.idle_test_period">
60
<!--  seconds  -->
</prop>
<prop key="hibernate.c3p0.acquire_increment">2</prop>
<prop key="hibernate.c3p0.max_statements">50</prop>
<prop key="hibernate.c3p0.preferredTestQuery">SELECT 1 FROM DUAL</prop>
<prop key="hibernate.show_sql">true</prop>
</props>

大部分条目没有在这里定义，使用默认值。如果这可能是问题所在，请告诉我，原因会很有帮助。

默认情况下 C3P0 连接的最大数量是 15 但我们几乎一直都超过这个限制并且不会遇到这个问题(同样它可能是 acquireIncrement 属性的 bcoz C3P0 支持这种情况下的连接)。

堆栈跟踪:

org.springframework.dao.DataAccessResourceFailureException: could not execute query; nested exception is org.hibernate.exception.JDBCConnectionException: could not execute query
at org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:625)
at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.convertHibernateAccessException(AbstractSessionFactoryBean.java:303)
at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.translateExceptionIfPossible(AbstractSessionFactoryBean.java:282)
at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:58)
at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:163)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy34.findByName(Unknown Source)
at a.b.c.d.e.f(A.java:941)
at a.b.c.d.e.f$$FastClassByCGLIB$$a171eb15.invoke(<generated>)
at org.springframework.internal.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:688)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:621)
at com.amazon.mobiusdatabase.activity.IMBatchActivity$$EnhancerByCGLIB$$42d90986.getLatestBatchByStatus(<generated>)
at com.amazon.coral.reflect.$2198.invoke(Unknown Source)
at com.amazon.coral.service.DefaultActivityInvoker.invoke(DefaultActivityInvoker.java:40)
at com.amazon.coral.service.ContinuationActivityInvokerFactory$1.invoke(ContinuationActivityInvokerFactory.java:92)
at com.amazon.coral.service.ActivityHandler.invoke(ActivityHandler.java:269)
at com.amazon.coral.service.ActivityHandler.before(ActivityHandler.java:157)
at com.amazon.coral.service.TransmutingContinuationHandler.before(TransmutingContinuationHandler.java:51)
at com.amazon.coral.service.Chain.componenteBefore(Chain.java:98)
at com.amazon.coral.service.Chain.before(Chain.java:76)
at com.amazon.coral.service.helper.ChainHelper.before(ChainHelper.java:103)
at com.amazon.coral.service.AbstractOrchestrator.doWork(AbstractOrchestrator.java:60)
at com.amazon.coral.service.PassiveOrchestrator.enqueue(PassiveOrchestrator.java:68)
at com.amazon.coral.service.GracefulShutdownOrchestrator.enqueue(GracefulShutdownOrchestrator.java:79)
at com.amazon.coral.service.helper.OrchestratorHelper.enqueue(OrchestratorHelper.java:44)
at com.amazon.coral.service.batch.BatchProtocolOrchestrator.enqueue(BatchProtocolOrchestrator.java:97)
at com.amazon.coral.service.bobcat.BobcatEndpoint.invoke(BobcatEndpoint.java:194)
at org.apache.catalina.valves.SSLValve.invoke(SSLValve.java:113)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11NioProcessor.process(Http11NioProcessor.java:894)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:719)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:2101)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
Caused by: org.hibernate.exception.JDBCConnectionException: could not execute query
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:97)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Last packet sent to the server was 1 ms ago.
at sun.reflect.GeneratedConstructorAccessor143.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2985)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2871)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3414)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2542)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1734)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1885)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeQuery(NewProxyPreparedStatement.java:76)
at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
at org.hibernate.loader.Loader.getResultSet(Loader.java:1808)
at org.hibernate.loader.Loader.doQuery(Loader.java:697)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
at org.hibernate.loader.Loader.doList(Loader.java:2228)
... 49 more
Caused by: java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(SocketInputStream.java:168)
at com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:113)
at com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:160)
at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:188)
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2428)

我们在对数据库触发选择查询时得到了这个。

Answer 1

也许连接没有正确关闭，所以你可以尝试大幅减少超时，看看你是否有同样的问题。

 <prop key="hibernate.c3p0.timeout">3000</prop>

同时您可以使用 JMX 分析器，例如 VisualVM监视 C3P0 连接，并直接在数据库服务器上查看是否存在“丢失”连接。