在延迟收集初始化后，Hibernate连接不会被释放 [英] Hibernate connections are not released after lazy collection initialization

问题描述

从3.6升级到hibernate 4.2.4后，数据库连接在初始化延迟收集后不会返回到池。因此，当用户数超过池中的连接数时，连接池会非常快速地耗尽。
类似的症状在 HHH-4808 中描述，但我们没有观察到这些Hibernate 3.1-3.6中的问题

相关设置：

  hibernate。 connection.autocommit = true 
 hibernate.connection.release_mode = after_transaction 
  

在初始化集合后没有公开交易。因此根据设置连接必须被释放。

在hibernate 3.6连接被释放后（通过从OneToManyLoader间接调用ConnectionManager.aggresiveRelease（））。
这对我们的使用场景非常重要。这种变化是故意的吗？是否可以通过一些设置组合来激活旧行为？

解决方案

我们找到了解决方法。是否有人看到缺点？

  EventListenerRegistry注册表=（（SessionFactoryImpl）sessionFactory）.getServiceRegistry（）。getService（EventListenerRegistry 。类）; 
 registry.appendListeners（EventType.INIT_COLLECTION，new InitializeCollectionEventListener（））; 
 
 public class InitializeCollectionEventListener implements InitializeCollectionEventListener {
 DefaultInitializeCollectionEventListener defaultListener; 
 InitializeCollectionEventListener（）{
 defaultListener = new DefaultInitializeCollectionEventListener（）; 
 
 public void onInitializeCollection（InitializeCollectionEvent pEvent）throws HibernateException {
 defaultListener.onInitializeCollection（pEvent）; 
 SessionImpl si =（SessionImpl）pEvent.getSession（）; （）&&！si.isClosed（）&& si.isConnected（）&& 
 si.getConnectionReleaseMode（）。equals（ConnectionReleaseMode.AFTER_TRANSACTION ））{
 si.getTransactionCoordinator（）。getJdbcCoordinator（）。getLogicalConnection（）。aggressiveRelease（）; 
} 
} 
 
} 
  

After upgrading to hibernate 4.2.4 from 3.6 database connections are not returned to pool after initialisation of lazy collection. As a result connection pool is exhausted very quickly when number of users exceeds number of connections in the pool. Similar symptoms are described in HHH-4808 but we haven't observed these problems in Hibernate 3.1-3.6

Relevant settings:

hibernate.connection.autocommit=true
hibernate.connection.release_mode=after_transaction

After collection is initialized there is no open transaction. So according to setting connection has to be released.

In hibernate 3.6 connection was released (through indirect call to ConnectionManager.aggresiveRelease() from OneToManyLoader). This is very critical change for our usage scenario. Was this change intentional? Is it possible to activate old behaviour through some combination of settings?

解决方案

We found a workaround. Does anybody see drawbacks?

EventListenerRegistry registry = ((SessionFactoryImpl)sessionFactory).getServiceRegistry().getService(EventListenerRegistry.class);
registry.appendListeners(EventType.INIT_COLLECTION, new InitializeCollectionEventListener());

public class InitializeCollectionEventListener implements InitializeCollectionEventListener{
    DefaultInitializeCollectionEventListener defaultListener;
    InitializeCollectionEventListener(){
        defaultListener = new DefaultInitializeCollectionEventListener();
    }
    public void onInitializeCollection(InitializeCollectionEvent pEvent) throws HibernateException {
        defaultListener.onInitializeCollection(pEvent);
        SessionImpl si = (SessionImpl) pEvent.getSession();
        if (!si.isTransactionInProgress() && !si.isClosed() && si.isConnected() && 
                si.getConnectionReleaseMode().equals(ConnectionReleaseMode.AFTER_TRANSACTION)){
            si.getTransactionCoordinator().getJdbcCoordinator().getLogicalConnection().aggressiveRelease(); 
        }
    }

}

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