Question

我使用的是c3p0 0.9.2.1，GWT 2.6.0，SQLServer 2012。

我从c3p0

获得了间歇性的stackTrace

[2015-Feb-03 16:30:12] - [INFO ] - A checked-out resource is overdue, and will be destroyed: com.mchange.v2.c3p0.impl.NewPooledConnection@14bc0e
[2015-Feb-03 16:30:12] - [INFO ] - Logging the stack trace by which the overdue resource was checked-out.
java.lang.Exception: DEBUG STACK TRACE: Overdue resource check-out stack trace.
    at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:555)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutAndMarkConnectionInUse(C3P0PooledConnectionPool.java:755)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:682)
    at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:140)
    at org.hibernate.c3p0.internal.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:89)
    at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:380)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:228)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:171)
    at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.connection(StatementPreparerImpl.java:63)
    at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$5.doPrepare(StatementPreparerImpl.java:162)
    at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$StatementPreparationTemplate.prepareStatement(StatementPreparerImpl.java:186)
    at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.prepareQueryStatement(StatementPreparerImpl.java:160)
    at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1884)
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1861)
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1838)
    at org.hibernate.loader.Loader.doQuery(Loader.java:909)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:354)
    at org.hibernate.loader.Loader.doList(Loader.java:2551)
    at org.hibernate.loader.Loader.doList(Loader.java:2537)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2367)
    at org.hibernate.loader.Loader.list(Loader.java:2362)
    at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:126)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1678)
    at org.hibernate.internal.CriteriaImpl.list(CriteriaImpl.java:380)
    at net.impro.portal.server.model.dao.CommsQueueDaoImpl.getOldestRecords(CommsQueueDaoImpl.java:54)
    at net.impro.portal.server.engine.uploader.AbstractBiometricUploader.getOldestRecords(AbstractBiometricUploader.java:217)
    at net.impro.portal.server.engine.uploader.UploaderMorpho$$EnhancerByGuice$$9212bdc2.getOldestRecords(<generated>)
    at net.impro.portal.server.engine.uploader.AbstractUploader.getSomeQueueData(AbstractUploader.java:222)
    at net.impro.portal.server.engine.uploader.UploaderMorpho$$EnhancerByGuice$$9212bdc2.getSomeQueueData(<generated>)
    at net.impro.portal.server.engine.uploader.AbstractBiometricUploader.processLoop(AbstractBiometricUploader.java:92)
    at net.impro.portal.server.engine.uploader.AbstractUploader.run(AbstractUploader.java:172)
    at java.lang.Thread.run(Unknown Source)

所以，它告诉我在指定的超时时间内我没有完成连接

<property name="hibernate.c3p0.debugUnreturnedConnectionStackTraces" value="true" />
<property name="hibernate.c3p0.unreturnedConnectionTimeout" value="10" />

我无法理解这是怎么回事。我的代码非常简单......

@Transactional
 protected void getSomeQueueData() {
   logger.error("+Entered Thread " + Thread.currentThread());
   //A little clumsy here but I dont see anything wrong
   final CommsQueueDao commsQueueDao = InjectHelp.requestNewInstance(CommsQueueDao.class);
   List<CommsQueue> qData = getOldestRecords(commsQueueDao, MAX_LOCAL_QUEUE_SIZE);
   Iterator<CommsQueue> iterator = qData.iterator();
   //Iterate the result, pack it into a local queue
   //...         
   logger.error("-Exit Thread " + Thread.currentThread() + " " + stuffToSend.size());
 }

@Transactional
  protected List<CommsQueue> getOldestRecords(CommsQueueDao qDao, int fetchSize) {
  return qDao.getOldestRecords(getBioAddress(), fetchSize);
}


//FROM MY DAO CLASS
public List<CommsQueue> getOldestRecords(BioAddress bioAddress, int maxRecords) {
  Criteria cr = getSession().createCriteria(CommsQueue.class);
  cr.add(Restrictions.eq("bioAddress", bioAddress));
  cr.addOrder(Order.asc("id"));
  cr.setMaxResults(maxRecords);
  return cr.list();
}

启动时，25个线程启动，每个线程调用getSomeQueueData（）。大约1/10次失败。我检查调试输出，发现每个线程已成功进入并退出方法，如预期的几秒钟，所以为什么c3p0告诉我连接仍在使用？只是为了澄清，@ Transaction是guice，而不是spring。

--- --- EDIT 我花了很多时间研究这个问题，只会变得更加令人费解......

我还将c3p0更新为0.9.5

@Transactional由于某种原因似乎不稳定。偶尔它不会被调用。我检查通过我的DAO的每个方法的堆栈跟踪，每隔一段时间，它表示拦截器处理已被跳过??。

在我的DAO中，我有一个getSession（）方法，当我添加100ms的任意睡眠时，几乎每个stackTrace都指示已跳过注释。

此外，这些设置几乎每次都会发生问题

<property name="hibernate.c3p0.maxPoolSize" value="20" />
<property name="hibernate.c3p0.minPoolSize" value="1" />
<property name="hibernate.c3p0.numHelperThreads" value="1" />

......这些设置很少发生问题

<property name="hibernate.c3p0.maxPoolSize" value="20" />
<property name="hibernate.c3p0.minPoolSize" value="20" />
<property name="hibernate.c3p0.numHelperThreads" value="20" />

完全删除c3p0似乎完全解决了我的测试所揭示的问题。

我已经读过，对于我们使用guice和我一直小心避免这种反映的情况，最后使用finally是值得注意的。对我来说，这些症状太奇怪了。有时似乎guice没有正确绑定我的类，有时它似乎是一个c3p0错误。

哦，我已经检查过我使用的是com.google.inject.persist.Transactional。

Answer 1

在没有解决问题的情况下尝试了替代池库，我将注意力转向了依赖注入。我认为这个问题与guice托管类的构造函数中存在的代码有关。如果该代码的效果有可能调用标记为@Transactional的方法，那么在“跳过”事务注释的地方会出现此问题。

这似乎对我有意义，所以我从构造函数中移除了它。在我确信这是解决方案之前，我会继续监控它。

c3p0连接已逾期

1 个答案: