Hi all This is a strange problem. We have an ASP.NET MVC application. We have a problem where if you close a page before it has finished loading, then it is impossible to get in to the application again without closing all your browser windows. So, this is the sequence of events: Load application - everything works fine Load a page - while it is loading close the browser/tab Open a new tab and browse to application -> ** nothing loads ** Close all open browsers (e.g. Chrome) Reload browser Navigate to application -> works ok. Has anyone seen this before? If I press the pause button on the debugger while the page is loading it just tells me nothing is executing. I occasionally get something like below where it looks like a task is awaiting a scheduled task, but this is all in Microsoft code. Any thoughts where I can start looking? Thanks

I sounds like you are performing some cookie logic. the browser reset clears the cookies. you could just use the browser debug utilities, to determine the cookie (just delete one by one each site cookie until it works).

So, basically I ended up just making my own session manager, and this has solved the problem. To me it looks like the ASP.NET Session manager isn't really fit for purpose any more. It might have been in the olden days, but now with multiple ajax calls being common, and the fact that a long running operation can leave the site completely unusable I think my advise to anyone would just be to avoid using it altogether.

Page hangs if load interrupted

William Buchanan 61

Hi all

This is a strange problem. We have an ASP.NET MVC application. We have a problem where if you close a page before it has finished loading, then it is impossible to get in to the application again without closing all your browser windows. So, this is the sequence of events:

Load application - everything works fine
Load a page - while it is loading close the browser/tab
Open a new tab and browse to application -> ** nothing loads **
Close all open browsers (e.g. Chrome)
Reload browser
Navigate to application -> works ok.

Has anyone seen this before?
If I press the pause button on the debugger while the page is loading it just tells me nothing is executing. I occasionally get something like below where it looks like a task is awaiting a scheduled task, but this is all in Microsoft code.

Any thoughts where I can start looking?

Thanks

Yijing Sun-MSFT 7,091 Reputation points

2021-09-27T09:31:15.937+00:00

Hi @William Buchanan ,
According to your description, I haven't seen what caused it for the time being. Maybe vs setting, maybe the browser. Or if you have logined in?
You could try to change the broswer.

Best regards,
Yijing Sun

2 answers

Bruce Barker 801 Reputation points

2021-09-27T15:23:14.44+00:00

I sounds like you are performing some cookie logic. the browser reset clears the cookies. you could just use the browser debug utilities, to determine the cookie (just delete one by one each site cookie until it works).
Please sign in to rate this answer.
William Buchanan 61 Reputation points

2021-09-28T03:35:46.41+00:00

Hi Bruce
Thanks for the tips. Very strange - it doesn't even seem to get that far from what I can see. What I notice in the Network tab is that it says the request is 'stalled'. The response tab is empty. So it looks like nothing has even made it's way back to the browser.

That said, I went in to the cookie storage in chrome and 1 by 1 deleted all cookies for localhost. There was no difference until I deleted the ASP.NET_SessionId cookie - at which point the login page appeared again. So - does that give any clues to the problem? Where could I start looking?

See images below...
Thanks

William Buchanan 61 Reputation points

2021-09-28T06:08:20.367+00:00

Ok I have made some progress....!

What I have noticed is that the ASPStateTempSessions table has a 'Locked' column. I notice that this is set to 1 when the page starts loading - obviously killing the browser tab means that the request ends, and the Locked column stays at 1.

If I then reload the site, it sits there doing nothing as usual - but as soon as I manually update the Locked column to 0 then the page magically starts to load.

So it looks like something is locking the session, and then it is impossible for anything else to proceed, and it would appear that the requests queue up until the lock is released...

The strange thing is that we don't really use the session for much other than login, so I assume there is something else which is doing this. Does anyone know how I can find what is accessing the session, or some way to unlock the session when new requests come in?

Thanks

Yijing Sun-MSFT 7,091 Reputation points

2021-09-29T06:36:06.963+00:00

Hi @William Buchanan ,
Every request to a handler that has session state enabled will take a read or write lock. If you have an unlucky mix of requests, you can end up with many requests blocked while waiting for the 1 request with the lock to finish. You could use LeanSentry to diagnose 'Session lock".The diagnostic will show the function that took the lock.The solution of completely moving away from session state is reducing session locking by moving a bunch of state from sessions into cookies or app-wide caches.

Best regards,
Yijing Sun

William Buchanan 61 Reputation points

2021-09-29T06:53:47.547+00:00

The problem seems to be that the controller automatically locks the session, and doesn't unlock it until the call is finished. It does this even if I don't access the session.

I am debugging this in Visual Studio so I don't think LeanSentry will work...

It would be nice if it just didn't lock the session the whole time...

Yijing Sun-MSFT 7,091 Reputation points

2021-09-30T09:14:07.427+00:00

Hi @William Buchanan ,
As far as I think,there is a way to implement a Lockless SessionStateStoreProvider.MVC allows for the use of custom session state store providers through the inheritance of the SessionStateStoreProviderBase class (MSDN: Implementing a Session-State Store Provider, MSDN: Session-State Modes). A simple way to use this to our advantage is to use reflection to wrap the pre-existing in-memory session state store provider, InProcSessionStateStore, in a simple class that uses calls to InProcSessionStateStore methods for most of its method implementations. When we encounter locks in either of the methods that are used to retrieve a session, GetItem and GetItemExclusive, we immediately release them using ReleaseItemExclusive and then again attempt to retrieve the now-unlocked session. As a result, session becomes effectively lockless.

Best regards,
Yijing Sun
Sign in to comment

Use comments to ask for clarification, additional information, or improvements to the question.
William Buchanan 26 Reputation points

2021-10-12T23:32:04.817+00:00

So, basically I ended up just making my own session manager, and this has solved the problem.

To me it looks like the ASP.NET Session manager isn't really fit for purpose any more. It might have been in the olden days, but now with multiple ajax calls being common, and the fact that a long running operation can leave the site completely unusable I think my advise to anyone would just be to avoid using it altogether.
Please sign in to rate this answer.

0 comments No comments
Sign in to comment

Use comments to ask for clarification, additional information, or improvements to the question.

Share via

Page hangs if load interrupted

2 answers

Your answer