使用Hibernate高GC负载 [英] High GC load using Hibernate

问题描述

我使用Spring MVC + Hibernate开发了一个Web应用程序，并且在运行负载测试时看起来垃圾收集器过于频繁地被调用。恐怕这可能与我管理冬眠会议的方式有关。

I have developed a web application using Spring MVC + Hibernate and when running load tests it seems the Garbage Collector is being called too often. I am afraid it might have to do with the way I manage Hibernates session.

我有一个AbstractDao，它是我所有DAO对象的扩展：

I have an AbstractDao which all of my DAO objects extends:

public class AbstractDaoHibernateImpl {

    protected GenericDataBaseExceptionHandler exceptionHandler;
    private SessionFactory sessionFactory;  

    public AbstractDaoHibernateImpl() {
    }

    public void setExceptionHandler(GenericDataBaseExceptionHandler exceptionHandler) {
        this.exceptionHandler = exceptionHandler;
    }

    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
    }

    protected Session getSession() {
        return sessionFactory.getCurrentSession();
    }

}

在我定义的spring entity bean configuration我的每个DAO都是这样的：

In spring entity bean configuration I define each of my DAOs like this:

   <bean name="userDao" class="com.kelmer.dao.UserDaoImpl">
        <property name="sessionFactory" ref="SessionFactory" />
        <property name="exceptionHandler" ref="defaultSpringExceptionHandler" />
    </bean>

然后这是我的一个DAO的示例方法：

And then this is a sample method from one of my DAOs:

    @Override
    public EstacionVO findById(Long id) throws InstanceNotFoundException {
        User e = (User ) getSession().createQuery(SELECT_USER_BY_ID).setParameter("userId", id).uniqueResult();
        if (e == null) {
            throw new InstanceNotFoundException ("No user with provided Id", User.class);
        }
        return e;
    }

我真的可以看到任何可能导致内存泄漏的事情，这里没有真正的专家。我在做会话管理吗？我知道我从一些遗留代码中抽取了AbstractDao的代码，我担心这是内存问题的原因，因为没有明确的会话关闭或终结。

I honestly can see anything that might be causing a memory leak but then again I'm no real expert here. Am I doing session management right? I know I took the code from AbstractDao from some legacy code and I fear that's where the memory problem could be, since there is no explicit session closing or finalizing.

PS。对于事务管理，我在Spring上下文中使用< tx：annotation-driven /> ，并使用 @Transactional 。

PS. For transaction management, I am using <tx:annotation-driven /> in spring context and annotating each method with @Transactional.

推荐答案

乍一看，代码中似乎没有任何异常。

At first glance, there doesn't seem to be anything unusual in your code.

运行性能监视器以查看创建了哪些对象。

Run a performance monitor to see what objects are created.

除非问题不重要，否则很难看出性能通过查看代码和90％的时间而丢失，任何声明它一定是这个结果是错误的。

Unless the problem is trivial, it's hard to see where performance is lost by just looking at the code and 90% of the time, any statement "it must be this" turns out to be wrong.

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