Is there one kind soul out there who has the time to help me figure out why my application is intermittently hanging (and hopefully how to fix it)? I'm running a web program from VS2015 that accesses a SQL Server database. Sometimes I'll click on a link on my webpage and everything works fine. Other times, though, the little circle just spins forever, and it never comes back. It doesn't seem to be related to the database because one time I caught it hanging on a call to XmlSerializer serializer = new XmlSerializer(type);
I'm running the website in IIS Express on localhost on a Windows 10 laptop (16GB & plenty of disk). I also have ReSharper if anyone thinks that can help me diagnose the problem. I've been fighting with this for days and have no idea what else to do but hope that someone here will have pity on me.
Re: D Stanley's comments: "Do you have any logging? Can you run it in the debugger to see where it's hanging? Is there anything in the system event logs?"
There is logging, but only on caught exceptions. Nothing that will help the hang situation. I can run it in the debugger, but when it's hung I can't see where it's hung (it's in External Code). The Event Log does report a "perflib" error when I run the program. I can post that info if you think it would help.
More info. I installed Fiddler. When the application is hung, Fiddler is still going to town. The "Process" it's showing is "scriptedsandbox64", which is doing I/O and consuming CPU time.
I suggest you add lots more log messages to your code, something like:
DateTime.Now.ToString("o") "Starting xxx"
DateTime.Now.ToString("o") "Finished xxx"
where xxx is a name for some chunk of code. You suspect the problem is in external code, so wrap all those calls.
You can then see where the application spends excessive time. Once you have found the right area, then perhaps add more logging to focus in on the problem.
The answer to my hanging problem was to use Local IIS instead of IIS Express. Once I figured out how to set up the website for localhost and began running with Local IIS my hangs disappeared.
Related
So I've been trying to figure out why the application pool keeps crashing every now and then, and I've pinpointed the page that is cau seems to be causing the issue.
When I open the site in the browser, and visit the Shipping cart page (after adding stuff to the cart), the entire browser becomes unresponsive, and I open Task Manager, and see that IE (browser) is using 99% CPU, so I right-click > Create DUMP > Try to read DUMP but WinDBG does not seem to like DMP files; won't read them.
So I move on, and try to figure it out without the dump files. I fire up Visual Studio, open the site in question, and then follow the same process (add stuff to cart, then visit cart page). And to my surprise, everything is OK.
Not sure what to do now. Any suggestions? How would you determine the cause of the hanging, when everything runs perfectly, locally - and when everything used to run perfectly online, but no longer runs fine online?
If the browser becomes unresponsive and eats 99% CPU, that's a client side problem; it most likely doesn't have anything to do with IIS or your server side code.
Could it be that you have some javascript in your page is buggy and goes into a busy loop? I think it's worth a shot to test this (use either IE's developer tools (F12), Visual Studio's javascript debugging functionality, or FireFox in combination with FireBug).
Edit
It strikes me as odd that your AppPool crashes, and in doing so, causes the web browser to turn non-responsive. With non-responsive, do you really mean that the browser itself stops working (i.e. navigating a page back or going to another url such as google.com is impossible?)
Anyway, if you think the problems occur on the server-side, you could try the following things (in order of increasing effort):
After an AppPool crash, check the windows event log (run 'eventvwr' from a command prompt) and see what information that gives you.
View the IIS log (you might have to turn it on first), see if it contains any weird request patterns, such as your page getting hammered)
Run your website from IIS, but attach a debugger from Visual Studio (under Tools, Attach to process - include only managed code) to the IIS worker process (usually w3wp.exe). If your page throws an exception, VS should be able to catch it.
Add more tracing to your page, the Global.asax's Application_Error seems like a particularly good candidate.
I have a Silverlight project that we use internally that I wrote - and since we've not had any need to work on it, it's been a while since I've opened the project. I opened it up this morning and everything is fine in terms of building, but whenever I try to debug I get the following error:
Unable to start program "http://mymachinename/mywebsite/index.aspx"
Of course, running it in Firefox works fine but no symbols are loaded. Running without debugging still throws the same error but IE loads up anyway...
Navigating to the website in IE works fine - SL app opens up, loads data etc etc, all looks good
I've Googled this all morning (usually quite good at finding info) and been through all the questions on SO and I can't figure out what's going on - there doesn't seem to be any messages in the event log, there are no messages in any VS output window, the w3wp just terminates immediately after starting (probably due to there being an error trying to open IE). I've tried reinstalling IE, cleaning/rebuilding, using local dev server, creating a new web project, turning on/off settings in IE9 etc etc
Nothing seems to make a difference - anyone got any experiences of this and has fixed it without doing one of the things I've already done? Any other suggestions?
Thanks in advance!
UPDATE
Just to be clear in case anyone asks - I get this problem when creating a new web project - i.e. everything I said I'd tried (above) didn't change the behaviour. It showed the same error no matter what I'd done so far (that includes a NON SL web project)
I've also tried attaching the debugger to w3wp that is running (the standard IIS process) and I can't seem to get it to debug (no symbols are loading), but that might be another issue altogether. I'm going to look at that next and maybe if I figure that out it might lead to fixing this issue
UPDATE 2
Debugging in Firefox works - I attached to w3wp with no success, then realising my stupidity (SL being a client side app!) I attached to the plugin-container.exe that FF runs its plugins in. This works. I can probably do the same for IE and just attach to IE, but why won't it start up from VS?! hair pull
UPDATE 3
Just in case anyone asks, the default browser is set to IE in VS. Also I've managed to debug by attaching to IE, it just won't start IE from within VS - annoying but I can live with it for now. If anyone does have a suggestion though, feel free...
For anyone's information in case they have this same problem, it ended up being that the port I was running my site on was also running a SharePoint site!
I created a new site on port 81 and used that for dev - not sure what setting on the other site caused the issue but it ended up working on port 81.
I have recently rolled out a new ASP .Net application. This application uses .Net 4.0 and the Entity Framework 4. It is a "basic" CRUD application. I almost exclusively used the EntityDataSource for Data Access.
The users have reported "ocassional freezing" of the application (they all use IE 8). If the user closes his browser and starts back up, the app is fine. It happens maybe once or twice per day total, usually to the heavy users. (So, I have been leaning toward memory leack or some other kind of resource limitation.)
Until just a little while ago, I have never seen this happen. It dosn't leave anything in the Event Log on the client PC nor Server. Also, there is nothing in the IIS error logs or the SQL logs.
A little while ago, I finally got it to happen. I was switching all of my EntityDataSources to use a single Object Context per page. I downloaded the EF Profiler (which seems to be a great product) and it pointed out that I am using multiple object contexts on many of my pages, due to the fact that many of them have more than one EntityDataSource. So, I was cleaning all this up and testing each page, when lo and behold....IE stopped loading pages!
At first, the page started loading slowly (and this was a page that I had already modified to use a single Object Context, so although I still believe I need to implement this "singleton" pattern throughout all my pages, I guess it isn't the culprit! Anyway..), then at some point I received:
Message: Sys.WebForms.PageRequestManagerTimeoutException: The server request timed out.
Still, nothing in the Event Log. I also checked the IIS web logs and I don't see anything, but they are pretty tough to read with the naked eye, I may have to download a parser to make sure there is nothing in there.
Anyway, I decided to start up another window and navigate to my app, and sure enough that window worked fine, no problems. I went back to the windows that stopped responding, refreshed it, waited... went to the home page of my app (which is basically just some static html.. and nothing.. ). Next, I opened a new tab in the window that is currently frozen and that tab works fine. So, I go back to the window that can no longer load pages from my app and try some other web sites.... espn.com loads fine, msn.com loads fine, I then enter the URL for my app home page (and tried some other pages in my app) and NOTHING. IIS doesn't even log the attempts in its Log Files (its like IE has just decided not to do anymore "gets" for my localhost!). Finally, after waiting for a while (while I was typing this post) I now have this error message in that window:
Internet Explorer cannot display the webpage. What you can try: The problem can be caused by a variety of issues, including: BLAH BLAH BLAH...
So, I jump back to that window and it can still browse Internet sites just fine. But, once again when I try to go to any of the pages in my app, I get NOTHING (spinning blue circle in the tab). So, once again I start a new tab in that same browser and I can browse around my application just fine.
What has my app done to this browser instance that will no longer let it load any of its pages (in fact, it seems like it isn't even doing a GET on any of the apps pages, since there is nothing new in the IIS logs...except for when I load the pages in these other tabs and/or browser windows that work fine, so the logging is still working...)? I will be forever indebted to the person that can help me figure this out. I am not sure it will do much good, but I am going to leave this browser window up on the chance that someone can tell me some things to try to diagnose this problem. It feel like I am THIS close to figuring it out. I finally have a window up that is misbehaving. I am afraid to close the window or do a new build on the app until I get some good input on things to try....
I should add that when this happened to me, I was running on my local PC, so I was the only user and only had one window open to the app..
Although, I am completely stumped!
We had the same issue and seemed to fix it by adding the following JavaScript to all pages with ajax:
window.onunload = abortRequest;
function abortRequest() {
Sys.WebForms.PageRequestManager.getInstance().abortPostBack();
}
I hope this helps!
sounds like a request just takes too long to execute. A web-browser is only allowed to keep two concurrent connections to a single webserver unless you utilize http pipelining (which isn't well supported anyway). However, My experience is that this is per browser, not per tab.
This is why nothing shows up in your logs, because your browser never initiate a request because it is waiting for the page to finish loading before it can fetch another page. I would start looking into the last request initiated before the lockup, it is probably that page that locks for some reason and never finishes.
ASP.NET utilizes only one thread as long as all request are sequential. As soon as you fire up two request simultaneously, a new thread is initiated (Init() on HttpApplication is invoked), and that can cause intermittent errors if you do funky stuff on Init().
If you think this is related to EF, you might read up on how to avoid locking in multi-threaded environment (because a web application is very much multi-threaded however this usually kicks in a production environment).
Ugh, I feel your pain - I hate these types of issues. Here's my divide-n-conquer process when something like this is happening (adapted somewhat to your case):
Step 1 - Environment Visibility
Get yourself set up so you can roughly see inside your systems. Set up Performance Monitor, and add a couple of important counters (IIS Current Requests, ASP.NET Current Requests, SQL Server - Active Transactions). The idea here with the "active requests/transactions" counters is you want to find out which part of the system is holding on to the request.
Additionally, add counters for total request time in IIS and the DB (so you can see it climbing as something is hanging on).
On your client PC, set up Fiddler.
Step 2 - Reproduce Issue
Usually at this point, the application realizes you can see it and starts behaving perfectly. ;) Stop and make sure you can still reproduce the issue.
Step 3 - Take the DB out of the equation
Create 4 pages in your application:
Static HTML file (.htm) that will NOT go through the ASP.NET runtime engine. This is your baseline for raw IIS.
ASPX page with no tricks (no database access, no processing, just a simple page that ASP.NET can spit out)
ASPX page with one simple database call (of some size, maybe do a single big query or something)
ASPX page with some complex transactions (multiple queries, etc)
Step 4 - Reproduce and measure
Since this issue will probably be pretty obvious once you can see it, find the bottleneck with your performance counters and Fiddler. Your issue sounds like you could have an intermittent connectivity issue (either between client and web server or web server/SQL), especially if IE is giving you the "page cannot be displayed" error, but you should see that in Fiddler. On the server side, you should see one of those performance counters hanging.
well, sounds like the app is waiting for a database operation to complete but is locked, probably because of another operation.
Try using the SQL profiler to trace the activity, and isolate what processes are running for a long time.
You can differentiate the requests using the SPID column in the trace view, it contains a unique ID number for each session from your App.
I have new information regarding this issue.
The application uses Integrated Authentication. This causes every reqest to come back (twice) with access denied, before IE send the credentials.
I can't help but wonder if this is what could be causing the "time outs".
I implemented an Ajax "Loading" animation on every page that prevents the user from clicking a button until the previous request is completed and that has GREATLY diminished the amount of "freezes" the users are experiencing.
Although, it still happens somewhat often.
(xkcd)
I know that compiling nowadays is much faster than it was before. Yet, for me, it seems that compiling and especially running/debugging ASP.NET projects with the Visual Studio Web Development Server is incredibly slow.
Since the beginning of last summer, I've been working heavily on ASP.NET MVC projects. Of course, the best way to debug them is by using the web server that comes with Visual Studio. When doing that, I get horrendously slow loading times. Chrome dev tools typically report that loading one of my pages had a 3 minute wait time, followed by a short loading time.
I've seen these two questions, but they don't help. While I do most of my debugging work in Chrome, the same happens in IE.
Has anyone else had this problem before? If so, any tips?
Also, I doubt that the problem lies with the speed of my machine. This computer is really fast running Windows 7 and Visual Studio 2010, so I don't see why ASP.NET debugging should be so slow.
UPDATE: In his answer below, Jon Skeet suggested attempting to identify whether the problem is being caused by the environment or by the code itself. I created a brand new MVC project and ran it. The first test appeared to be much faster. However, after testing it a few more times, it's safe to say that the first test was an anomaly - usually, it takes as long as my big project (2 - 3 minutes). Thus, this is a problem with the environment. Thanks in advance for any help!
UPDATE #2: It's been a while since I updated this question. Here are some details I've gathered since my last update:
This delay is occuring on both of my development machines, both running Windows 7 and Visual Studio 2010
This delay is happening for all my MVC2 and MVC3 projects (but I haven't experimented with plain ASP.NET yet)
Plain/vanilla MVC projects experience the same delay as MVC projects with big codebases
Disabling IntelliTrace did not help
Disabling IPv6 did not help
I haven't found a solution for this problem, so I've been stuck with huge wait times. Does anyone know how to solve this?
There's no reason why it should take 3 minutes to start debugging something unless you've got something really strange going on.
I suggest you launch the debugger, try to navigate to a page and then just break into the debugger while it's loading. See where you're losing time. Maybe you're making some call on startup which is failing, but taking minutes to do so.
I've never experienced anything like what you're describing, which suggests it's either in your environment or in your code - and if it's a generally fast computer, that suggests it's somewhere in the code.
If you create a brand new MVC project and debug into that, does that take a long time?
You might also want to run Wireshark when you start debugging - see whether something in your app is trying to fetch a network resource of some description without you realising it.
This is due to the IPv6 DNS problem within Firefox and can be fixed by setting the network.dns.disableIPv6 setting to true within the about:config
Slow DNS response - Firefox on localhost and Visual Studio or Cassini
This is actually a known performance issue with MVC, caused by throwing a ton of exceptions internally on startup. If you have IntelliTrace turned on, this will wreck havoc with it. Try disabling IntelliTrace and see if that improves it at all.
Source: http://connect.microsoft.com/VisualStudio/feedback/details/535799/debugging-mvc-is-very-very-slow
Check out if this helps:
http://blogs.msdn.com/b/mahuja/archive/2008/07/08/resolving-very-slow-symbol-loading-with-vs-2008-during-debugging.aspx
I met the same problem these days, working under Win7, VS2010, and developing a Silverlight solution with 10+ projects. It takes about 3 minutes to launch IE, and waits 3 minutes to get back VS after closing IE. I overcame the problem by trying different ways. But the only valuable method:
Unload all projects not for debug
Start debug the solution (it works normal )
Reload other projects
VS works normal here. (VS works normal)
It seems the problem is just related with the VS environment on my side. It has nothing to do with ASP.NET Development Server or IIS.
I was having the same problem. It ended up being a problem with ColdFusion being installed on my local machine (as painful as it is for me to admit). ColdFusion puts Handler Mappings named AboMapperCustom-* that were causing the latency. I uninstalled ColdFusion because I no longer need it (thank God). Another solution could be to remove each AboMapperCustom entry through the web.config. Example:
<handlers>
<remove name="AboMapperCustom-15397" />
<remove name="AboMapperCustom-20358" />
<remove name="AboMapperCustom-47286" />
</handlers>
Make sure the 5-digits following AboMapperCustom- match those in your local IIS Handler Mappings.
HTH
On Visual Studio 2012 + Win10 x64, i've noticed that if you
go to the taskbar and find the asp.net dev server there,
right click it and do a "show details"
close the box (NOT 'stop', just close via 'x')
then the server loads almost instantly
I have an application (ABC) that I developed and it as a windows application (.exe). It is by itself quite a big application referring a lot of dll's.
However, now there is a requirement that demands that this application(ABC) be a part of an even larger application (XYZ). Hence, I had to change the project type of "ABC" from being a windows application to a class library, and by changing a few lines of code.
My problem is that, ever since I started using ABC as part of XYZ, the application started hanging if I dint perform any operation on it for 10 to 15 mins... I do not have any problems while running it as a separate application.
Any reasons why this might occur?
Any suggestions would be really appreciated...
Thanks,
Ram
Launch XYZ in the debugger. Wait for the app to hang, pause the debugger, and have a look at what each of the threads in your process are busy with.
It might also help to turn on "break on all exceptions"
You can also use remote debugging to debug the application whilst it is running on the user's machine. From your dev machine, you can attach to the process on the user's machine, and then do a debug break to see what the threads are doing.