我刚刚发现ASP中的每个请求。网络web应用程序在请求开始时获得一个会话锁，然后在请求结束时释放它!
如果你不明白这其中的含义，就像我一开始一样，这基本上意味着:
Any time an ASP.Net webpage is taking a long time to load (maybe due to a slow database call or whatever), and the user decides they want to navigate to a different page because they are tired of waiting, they can't! The ASP.Net session lock forces the new page request to wait until the original request has finished its painfully slow load. Arrrgh.
Anytime an UpdatePanel is loading slowly, and the user decides to navigate to a different page before the UpdatePanel has finished updating... they can't! The ASP.Net session lock forces the new page request to wait until the original request has finished its painfully slow load. Double Arrrgh!
那么有什么选择呢?到目前为止，我想出了:
Implement a Custom SessionStateDataStore, which ASP.Net supports. I haven't found too many out there to copy, and it seems kind of high risk and easy to mess up.
Keep track of all requests in progress, and if a request comes in from the same user, cancel the original request. Seems kind of extreme, but it would work (I think).
Don't use Session! When I need some kind of state for the user, I could just use Cache instead, and key items on the authenticated username, or some such thing. Again seems kind of extreme.
我真不敢相信ASP。Net微软团队在4.0版本的框架中留下了如此巨大的性能瓶颈!我是不是遗漏了什么明显的东西?为会话使用ThreadSafe集合有多难?
如果您的页面没有修改任何会话变量，您可以选择退出此锁的大部分。
<% @Page EnableSessionState="ReadOnly" %>
如果您的页面不读取任何会话变量，您可以选择完全退出该页面的锁。
<% @Page EnableSessionState="False" %>
如果没有页面使用会话变量，只需在web.config中关闭会话状态。
<sessionState mode="Off" />
我很好奇，如果“一个ThreadSafe集合”不使用锁，你认为它会做什么来成为线程安全的?
Edit: I should probably explain by what I mean by "opt out of most of this lock". Any number of read-only-session or no-session pages can be processed for a given session at the same time without blocking each other. However, a read-write-session page can't start processing until all read-only requests have completed, and while it is running it must have exclusive access to that user's session in order to maintain consistency. Locking on individual values wouldn't work, because what if one page changes a set of related values as a group? How would you ensure that other pages running at the same time would get a consistent view of the user's session variables?
如果可能的话，我建议您在设置会话变量之后尽量减少对它们的修改。这将允许您将大部分页面设置为只读会话页面，从而增加来自同一用户的多个同时请求不会相互阻塞的机会。
好的，非常感谢Joel Muller的贡献。我的最终解决方案是使用自定义SessionStateModule在这篇MSDN文章的最后详细说明:
http://msdn.microsoft.com/en-us/library/system.web.sessionstate.sessionstateutility.aspx
这是:
非常快地实现(实际上似乎比走提供者路线更容易)
使用了很多标准的ASP。开箱即用的网络会话处理(通过SessionStateUtility类)
This has made a HUGE difference to the feeling of "snapiness" to our application. I still can't believe the custom implementation of ASP.Net Session locks the session for the whole request. This adds such a huge amount of sluggishness to websites. Judging from the amount of online research I had to do (and conversations with several really experienced ASP.Net developers), a lot of people have experienced this issue, but very few people have ever got to the bottom of the cause. Maybe I will write a letter to Scott Gu...
对于遇到这个问题并且发现没有任何解决方案有用的Mono用户，您没有做错任何事情。
Mono (Issue #19618)中有一个bug，使得SessionStateModule上的SessionStateBehavior无用，所以在Web上设置SessionStateBehavior并不重要。config/pages, Application_BeginRequest，或者在控制器或动作上设置一个属性。什么都不行。我试过了。
然而，防止锁定的逻辑(在SessionStateModule上调用GetItem而不是GetItemExclusive)有一个限制:HttpHandler必须实现标记接口IReadOnlySessionState。
因此，我没有实现我自己的SessionStateModule，而是采用了一种不同的(有点笨拙的)方法。
供贵方考虑:
// Custom handler that derives from MvcHandler which implements IReadOnlySessionState
public class MvcReadOnlyHandler : MvcHandler, IReadOnlySessionState
{
public MvcReadOnlyHandler(RequestContext requestContext) : base(requestContext)
{
}
}
// Custom RouteHandler that derives from `MvcRouteHandler` which
// returns our very own `MvcReadOnlyHandler`
public class MvcConcurrentRouteHandler : MvcRouteHandler
{
protected override IHttpHandler GetHttpHandler(RequestContext requestContext)
{
return new MvcReadOnlyHandler(requestContext);
}
}
// On Global.asax.cs Application_Start, after all the Routes and Areas are registered
// change only the route handler to the new concurrent route handler
foreach (var routeBase in RouteTable.Routes)
{
// Check if the route handler is of type MvcRouteHandler
if (routeBase is Route { RouteHandler: MvcRouteHandler _ } route)
{
// Replace the route handler
route.RouteHandler = new MvcConcurrentRouteHandler();
}
}
因为现在路由器实现了ireadonlyessionstate，所以没有锁定会话id
希望当这个bug被修复时，我的解决方案将是多余的，但在那之前，我希望它能帮助到别人。
Important note: This solution basically makes storing items on the Session unsafe, I don't use this feature so for me it works. You can still add items since ReadOnly does not prevent writing, it is just not locking.
If you want to guarantee safe writing, you can add another extension method MapRoute to RouteCollection to use the new router, in order to register routes that doesnt lock. Like that you can register your routes to new MvcConcurrentRouteHandler router or to the existing one for writing.
这个关于允许每个会话并发请求的答案很棒，但它缺少一些重要的细节:
控件中允许每个会话并发请求的设置
更新的ASP .NET会话状态模块
Microsoft.AspNet.SessionState.SessionStateModuleAsync。这个设置是
支持任何可以使用此模块的提供者。
年长的
sessionstate模块System.Web.SessionState.SessionStateModule
不支持这个。
确保会话状态的使用是线程安全的或
会话中可能出现并发问题
摘要以启用此功能:
允许并发请求:
<appSettings>
<add key="aspnet:AllowConcurrentRequestsPerSession" value="true"/>
</appSettings>
确保使用更新的会话状态模块:
<system.webServer>
<modules>
<!-- remove the existing Session state module -->
<remove name="Session" />
<add name="Session" preCondition="integratedMode" type="Microsoft.AspNet.SessionState.SessionStateModuleAsync, Microsoft.AspNet.SessionState.SessionStateModule, Version=1.1.0.0, Culture=neutral" />
</modules>
</system.webServer>
