为什么在插入EF 4.1实体如此缓慢相比，ObjectContext的？ [英] Why is inserting entities in EF 4.1 so slow compared to ObjectContext?

问题描述

基本上，我一个事务中插入35000对象：

Basically, I insert 35000 objects within one transaction:

using(var uow = new MyContext()){
  for(int i = 1; i < 35000; i++) {
     var o = new MyObject()...;
     uow.MySet.Add(o);
  }
  uow.SaveChanges();
}

这永远需要！
如果我使用的基本 ObjectContex T（通过​​使用 IObjectAdapter ），它仍然缓慢，但需要大约20秒。它看起来像 DbSet＆LT;＆GT; 做一些线性搜索，这需要多长的时间...

This takes forever! If I use the underlying ObjectContext (by using IObjectAdapter), it's still slow but takes around 20s. It looks like DbSet<> is doing some linear searches, which takes square amount of time...

其他任何人看到这个问题？

Anyone else seeing this problem?

推荐答案

由于已经拉吉斯拉夫在评论所指出的，你需要禁用自动变化检测，以提高性能：

As already indicated by Ladislav in the comment, you need to disable automatic change detection to improve performance:

context.Configuration.AutoDetectChangesEnabled = false;

这变化检测是默认的的DbContext API中启用。

This change detection is enabled by default in the DbContext API.

为什么的DbContext 的行为与的ObjectContext API如此不同的原因是，<$ C的更多功能$ C>的DbContext API将调用 DetectChanges 的ObjectContext API函数内部>自动时变化检测已启用。

The reason why DbContext behaves so different to the ObjectContext API is that many more functions of the DbContext API will call DetectChanges internally than functions of the ObjectContext API when automatic change detection is enabled.

<一个href=\"http://blog.oneunicorn.com/2012/03/11/secrets-of-detectchanges-part-2-when-is-detectchanges-called-automatically/\">Here你可以找到的那些称之为 DetectChanges 默认功能的列表。它们是：

Here you can find a list of those functions which call DetectChanges by default. They are:

• 的添加，连接，查找，本地或删除的成员 DbSet


• 的 GetValidationErrors ，输入或的SaveChanges 成员在的DbContext


• 在项方法 DbChangeTracker

• The Add, Attach, Find, Local, or Remove members on DbSet
• The GetValidationErrors, Entry, or SaveChanges members on DbContext
• The Entries method on DbChangeTracker

尤其添加通话 DetectChanges 负责您遇到的糟糕表现。

Especially Add calls DetectChanges which is responsible for the poor performance you experienced.

我此相反的的ObjectContext API调用 DetectChanges 仅在自动的SaveChanges ，但不是在 ADDOBJECT 和上述其他相应的方法。这就是为什么在默认性能的ObjectContext 更快。

I contrast to this the ObjectContext API calls DetectChanges only automatically in SaveChanges but not in AddObject and the other corresponding methods mentioned above. That's the reason why the default performance of ObjectContext is faster.

他们为什么要引进这么多的功能在的DbContext 这个默认的自动变化检测？我不知道，但似乎禁用它，并呼吁 DetectChanges 手动在适当的点被认为是的高级，可以很容易地引入微妙的错误到你的应用程序，以便使用[它]小心。

Why did they introduce this default automatic change detection in DbContext in so many functions? I am not sure, but is seems that disabling it and calling DetectChanges manually at the proper points is considered as advanced and can easily introduce subtle bugs into your application so use [it] with care.

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