如何正确使用 NHibernate ISession 对象 - 会话已关闭！错误 [英] How to properly use a NHibernate ISession object - Session Is Closed! errors

问题描述

我在 NHibernate 中遇到了 ISession 的问题.我不断收到会话已关闭！"错误.有人可以告诉我正确的模式，包括以下方法的定义以及何时使用每种方法:

I'm running into issues with my ISessions in NHibernate. I keep getting "Session Closed!" errors. Can some one please show me the correct pattern including a definition of the following methods and when to use each:

ISession.Close()
ISession.Dispose()
ISession.Disconnect()

这是我的问题.我有一个回调设置来触发一个过程，每隔几分钟就向玩家颁发徽章.但是我不断收到会话已关闭！"关于无法关联集合的错误或错误.

Here's my problem. I have a callback setup to fire off a process that awards badges to players every couple of minutes. However I keep getting "Session Closed!" errors or errors about not being able to associate collections.

这是我的存储库:

public class NHibernateRepository : IRepository
{
#region Fields

private ISession _session;
private readonly ISessionFactory _sessionFactory;
#endregion

#region Constructors

public NHibernateRepository(ISessionFactory sessionFactory)
{
    _sessionFactory = sessionFactory;
}

#endregion

#region IRepository Implementation

public ISession OpenSession()
{
    _session = _sessionFactory.OpenSession();
    return _session;
}

public IQueryable<TModel> All<TModel>()
{
    return _session.Linq<TModel>();
}

public void Save<TModel>(TModel model)
{
    _session.Save(model);
}
public void Update<TModel>(TModel model)
{
    _session.Update(model);
}
public void Delete<TModel>(TModel model)
{
    _session.Delete(model);
}

public ITransaction BeginTransaction()
{
    return _session.BeginTransaction();
}
public void Flush()
{
    _session.Flush();
}
#endregion

}

这是我的用法.存储库通过结构图注入

Here's my usage. The repository is getting injected via Structure Map

private Object _awardBadgesLock = new object(); //In case the callback happens again before the previous one completes

public void AwardBadges()
{

    lock (_awardBadgesLock)
    {
        using(session = _repository.OpenSession())
        {
            foreach (var user in _repository.All<User>().ToList())
            {
                var userPuzzles = _repository.All<Puzzle>().ByUser(user.Id).ToList();
                var userVotes = _repository.All<Vote>().Where(x => x.UserId == user.Id).ToList();
                var userSolutions = _repository.All<Solution>().ByUser(user.Id).ToList().Where(x => !userPuzzles.Select(y => y.Id).Contains(x.PuzzleId));
                var ledPuzzles = GetPuzzlesLedByUser(user.Id);

                AwardPlayerBadge(user, userSolutions);
                AwardCriticBadge(user, userVotes);
                AwardCreatorBadge(user, userPuzzles);
                AwardRidlerBadge(user, userPuzzles);
                AwardSupporterBadge(user, userVotes);
                AwardPopularBadge(user, userPuzzles);
                AwardNotableBadge(user, userPuzzles);
                AwardFamousBadge(user, userPuzzles);
                AwardLeaderBadge(user, ledPuzzles);

                using (var tx = _repository.BeginTransaction())
                {
                    _repository.Update(user);
                    tx.Commit();
                }
            }
        }
    }

}

推荐答案

问题在于 ISession 不是线程安全的.在单独的线程上触发了多个方法，这些方法都创建了一个 ISession 实例.问题实际上在于它们都共享相同的 SessionFactory.Image 这两种方法都在单独的线程上触发:

The issue lies in the fact the ISession is not thread-safe. There were multiple methods being fired on separate threads that all created an instance of ISession. The issue was really with the fact that they all shared the same SessionFactory. Image both of these methods are fired off on separate threads:

ISessionFactory _sessionFactory;

void MethodOne()
{
   using(ISession session = _sessionFactory.OpenSession()) 
   {
       //Do something with really quick with the session
       //Then dispose of it
   }
}

void MethodTwo()
{
   //OpenSession() actually returns the same instance used in the 
   //previous method that has already disposed of the object;
   using(ISession session = _sessionFactory.OpenSession()) 
   {
       //Do something with a session that has already been disposed
       //throws errors

   }
}

我修复它的方法基本上是在这些场景中放弃 NHIbernate，而是调用存储过程.我认为无论如何在我的情况下它的性能更高.

How I fixed it was basically ditching NHIbernate in these scenarios and called stored procs instead. I think it turned out to be more performant in my situation anyway.

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