Hello Eric,

Our Developer teams would enhance our mechanism to avoid this issue as we talked in previous thread.
Except this issue, Is there anything else that crash WebGrid?

Regards,
Handy

Hi Handy,

This issue here is not related to any other thread in Community forum. What do you mean with "enhance our machanism to avoid this issue"? Do you mean with "previous thread" the issue with the Input Validation and the intended change to JSON? This is not related to the above mentioned bug.

Eric

Hi Eric,

I was talking about this issue because you said that add (ç = char 0x02) and (¢ = char 0x03).
http://www.intersoftpt.com/Community/WebGrid/How-to-avoid-XML-in-WebGrid-AJAX-postback/

If this is a different issue, please let us know more details such as in sample that can replicate this issue.

Regards,
Handy

Hi Handy,

Yes, this is a completely different issue and not related to the other thread you mentioned in any way. As mentioned in my original post, I cannot give you a sample as this happens only about once a month on our production server. I don't even have access to our production server. But from the logged traffic (also in my original post), you can clearly see that the problem is related to the WebGrid.

What I would like to know is under what circumstances this type of traffic can happen (WebGrid answering with an empty response). If you need any additional logging information, I can also try to get that, but I think the above information is sufficient.

Regards,

Eric

Hello Eric,

Ok, I will forward the information to our developer teams. I will back to you asap and thank you for your information.

Regards,
Handy

Hi Handy,

Caching? Could you be more specific with this question? Do you need information about a webserver setting or an option for WebGrid? I'm not sure what you want me to check.

Yes, we are using the InitializeDataSource event on all pages.

It happens on all WebGrids that are on different pages. I remember at least two totally different pages where it occurs. Pages that do not use a WebGrid work fine at the time of the problem. And as long as you don't cause any postback even on the pages with the WebGrid, the pages also appears fine.

Does this help anything?

Eric

Hello Eric,

I mean if there is any DataCaching for WebGrid that you used. You can also ready more about DataCaching in our WebGrid documentation. Or you told us about your WebGrid and WebServer settings.

Regards,
Handy

There should be absolutely no data caching. If you want me to check any specific setting or option or anything, please let me know.

Hello Eric,

Ok, Can you let us know your WebGrid settings? You haven't answered that yet. I might also need your web.config. Maybe other settings in your application can also cause this issue.

Regards,
Handy

Hi Handy,

Here the requested infos: The web.config, and two grids that are both known for causing the error when the server is in that errornous state.

Eric

Hello Eric,

Thank you for the detaisl. I will forward this to our developer teams.

Regards,
Handy

Hello Eric,

Our developer teams need more additional information such as the code behind of your pages. Can you provide the details to us?

Regards,
Handy

Hi Handy,

Actually I cannot post the full code or so. I can give you information on what events we use or whatever information you need.

We might also be able to add additional logging into every event or whatever you want. I'm just expecting some help to narrow down the problem. I understand that it is very difficult for you to help if you cannot reproduce it on your side. But I need some information on where to continue logging/debugging. Right now I can only see that it's a problem caused by WebGrid.

Eric

Hello Eric,

That would be very difficult if you only give some of snippet codes. If it is confidential, would you mind to send the code in email?

Regards,
Handy

I will have to talk with our compliance department if it is possible to send you more details by email. Please give me the email where you want to receive this. Maybe I can send you the code parts of the pages that crash if I anonymize some things there. Also you don't have the database, which we cannot disclose, so the code won't work anyway - they will remain snippets.

But in any case, please note that this won't help you to reproduce the problem. Even if you would set up the same project in a working environment, it might not happen for you. Maybe upgrading to a newer operating system (currently Windows 2000 Advanced Server) or a newer WebGrid version may help.

Also, you cannot tell if it is solved if it doesn't occur for one month, because it only happens from time to time. So how would you debug this? I can try to setup the same debugging environment (or logs). So if you need to know what happens with a specific request, I can try to log that. Just tell me what you need to watch. I think this is the best approach.

Thanks,

Eric

Hello Eric,

It's true that it would be hard to investigate the issue since we could not run the sample in here.
However, we would like to try our best based on any details that you can provide to us.
After discussed with our developer teams, they asked for the code behind. You can send the details into technical@intersoftpt.com.

Regards,
Handy

Hello Eric,

Ok, Thank you for your cooperation. But it seems you forgot to attach the log files.

Regards,
Handy

Hi Handy

My attachment was included with my email. I received a receipt-confirmation and a ticket number [IS-B7377DC1-838C-4E46-A2A2-AC67D615C169] {96804}

Please look at the ZIP file called crash2.zip in there. There is a subfolder in the ZIP called crashlog_cleartext with seven text files in it. Let me know if you still cannot find it.

Thanks,

Eric

Hello Eric,

Ok, Thank you for pointing me the direction.
Do you get unhandled error about "Unable To Communicate with Server"?
This error usually happens when the response fails returns from server. It can be caused by several causes such as Memory low or heavy server process. The issue commonly did not come from WebGrid. But I will let our developer teams know about your information.

Regards,
Handy

Hi Handy,

No, I don't get an error message. The OnUnhandledError client-side event gets triggered as mentioned above. Maybe if it would not be handled then this communication error would appear instead.

What I do know already is that at that time the server was NOT under heavy load. I don't know the memory condition though. But the fact that only WebGrid is affected is quite strange.

Also, restarting the WebServices (IIS) does not help, only rebooting the server.

Regards,

Eric

Hello Eric,

Ok, I will let you know the update after got news from our developer teams.

Regards,
Handy

any update yet?

Hello,

As far we checked your code, it seems you did not bind WebGrid in proper event. Sometimes, this can return unexpected result. Please use your binding code in InitializeDataSource event instead of PageLoad.

Regards,
Handy

Hi Handy,

This is by design. Maybe there are other ways to implement this. But I think you don't want to start a discussion on the implementation design here, right? We are talking about a server crash once a month caused by WebGrid.

Thanks,

Eric

Hello Eric,

It's true that by design, All binding should be handled in InitializeDataSource event. You can also bind at Page_Load. But sometimes, it can return unexpected result such as no data return in "some condition and scenario", "get some random unhandled error", or even incorrect random data load.

Regards,
Handy 

Hi Handy,

I don't see what you want to tell me. Does this mean that crashing once a month is "normal" if we use binding in Page_Load event? I hope not. We also won't change the implementation and make a new release of our application just to try out if it might happen less frequently or go away with a new code design.

In any case there is some weird bug in WebGrid and I would like to get this solved somehow.

Thanks,

Eric

Hello Eric,

I don't say it is normal or not. But it might happen since you used Page_Load for your DataBinding. Using InitializeDataSouce event is the correct and the best way for the databinding. 
I suggest you to read "Event sequence of server side events" in our documentation to understand our WebGrid behaviour. 

Regards,
HAndy

Hi Handy,

If you have a documentation, then I have never seen it. And I also cannot find it. On your old website there were a few articles, but they are gone now. On my PC there is no documentation and I installed the full WebUI.Studio (although I only need the WebGrid). On your website I also cannot find a documentation. I found a chm file for download, but that doesn't run on a network drive (desktop) and if copied to some local drive (I'm an admin, so I can do that) I can see that it only contains framework documentation. I never saw a document describing all events and properties etc. of WebGrid. If I cannot find it, then probably many other users have the same problem. This is something your company should work on. Please provide me with a link to your mentioned document "Event sequence".

But even if I would find the document "event sequence", does it say that I am not allowed to do data binding in Page_Load event?

Please note that all this code was not written by me. I don't want to rewrite big progams of other people that left the company. I just want to fix the problems. And crashing is a big problem.

Also, please note that this crash happens on all pages that use the WebGrid. One of the pages that crash were written completely new with your help and don't do data binding in Page_Load event (but contain several grids and use complicated events and mutual updates on both client and server side). I didn't want to send you that page, just because it's too complicated and preferred a simple page.

Can I assume that you are still investigating the root cause?

Thanks,

Eric

Hello,

Yes, we are still investigating this issue. But you need to rewrite the code so It can run in the correct behaviour. Please move the code to the correct event which it should be placed. I believe that this documentation has contains this information. We haven't tested to open the documentation in network drive. But you should have our documentation when installing the product.

Once again, The binding should not place in page load. It should be placed in InitializeDataSource event.
We can only continue the investigation after you moved the code.

Regards,
Handy

I found your mentioned documentation now - it's difficult to find as there is no file for it. It also doesn't tell any details about the implementation of the binding.

I think I need to restate that this bug is not related to one specific page, so changing one page with a not ideal binding won't help. If you want to look at another page that also crashes and does not use binding in page load, please look through support issue [IS-5D86A204-3663-4A01-B709-2342F10A6A49].

As soon as the webserver is in a certain condition, all pages that contain a WebGrid do crash - but only after a postback, like when opening a node in the grid.

I requested infos from the server team about memory, CPU and network load and will update here if there is any news. But for now, you can assume there was no special condition.

Thanks,

Eric

Hi Eric,

Ok, I will try to check into our system based on IS-5D86A204-3663-4A01-B709-2342F10A6A49 ticketID and will let you know when there is an update from our developer teams.

Regards,
Handy  

Currently it's crashing about once a week, like today again. What I saw is that on another page it crashes when loading data on demand (opening a node in a grid). This is somewhat different from the other crashes, as there is a server-side crash involved, not only no data being responded to the client. But as this is probably the same internal problem, maybe it helps you find the cause. Here are the details.

Protected Sub grdMain_InitializeSelfReferenceDataSource(ByVal sender As Object, ByVal e As ISNet.WebUI.WebGrid.ChildTableDataSourceEventArgs) Handles grdMain.InitializeSelfReferenceDataSource
	Dim ds As DataSet = Nothing
	Dim MainGridId As String = e.ParentKeyValues("Unique_ID").ToString()

	If MainGridId.StartsWith("F_") Then
		ds = GetData(GetNumFromMainGridId(MainGridId))
	End If

	Dim dt As DataTable = CType(e.DataSource, DataTable)
	If Not IsNothing(ds) AndAlso Not IsNothing(ds.Tables(0)) AndAlso ds.Tables(0).Rows.Count > 0 Then
		dt.Merge(ds.Tables(0), True, MissingSchemaAction.Error)
	End If
End Sub

This crashes somehow. The full error message is not being displayed, because the client redirects to an error page. But tracing the HTTP traffic I can see the error message. The error message is the usual yellow ASP.NET error message and it says: Target table Table missing definition for column Location.

Stack trace says:

[DataException: Target table Table missing definition for column Location.]
   System.Data.Merger.MergeSchema(DataTable table) +632
   System.Data.Merger.MergeTableData(DataTable src) +31
   System.Data.Merger.MergeTable(DataTable src) +187
   System.Data.DataTable.Merge(DataTable table, Boolean preserveChanges, MissingSchemaAction missingSchemaAction) +128
   Modules_MainPage.grdMain_InitializeSelfReferenceDataSource(Object sender, ChildTableDataSourceEventArgs e) +251
   ISNet.WebUI.WebGrid.WebGrid.OnInitializeSelfReferenceDataSource(WebGridTable table, Object dataSource, String parentConstraints, String customReqData) +720
   ISNet.WebUI.WebGrid.DataBinding.???(WebGridTable table, DataView view) +210
   ISNet.WebUI.WebGrid.DataBinding.????(WebGrid grid, WebGridTable table, DataView dataSource) +4633
   ISNet.WebUI.WebGrid.DataBinding.??(DataView dataSource, String dataMember, String request) +562
   ISNet.WebUI.WebGrid.DataBinding.DataBind(Object dataSource, String dataMember) +674
   ISNet.WebUI.WebGrid.WebGrid.??() +44
   ISNet.WebUI.ISNetControl.ControlRequestHandler(Object sender, EventArgs e) +293

[Exception: Target table Table missing definition for column Location.]
   ISNet.WebUI.ISNetControl.ControlRequestHandler(Object sender, EventArgs e) +446
   System.EventHandler.Invoke(Object sender, EventArgs e) +0
   System.Web.UI.Control.OnPreRender(EventArgs e) +2069340
   System.Web.UI.Control.PreRenderRecursiveInternal() +77
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1360

What I read out of this is this: My code correctly gets the data from the database and tries to merge it into the existing WebGrid data. This fails, because the grid doesn't provide the correct column definition anymore. e.DataSource is probably empty or something like that. I assume because of another problem that happened within WebGrid somehow.

Maybe this additional info helps in some way.

Eric

Hi Eric,

Thank you for the information. I will forward this to our developer teams.

Regards,
Handy

Hello Eric,

Based on my discussion with our developer teams, it seems you still need to move the code in the proper event, InitializeDataSource. Crash in InitializeDataSorce might be not related issue with previous one.
If data returns from server already got time out, of course WebGrid would return unhandled error.

Regards,
Handy

Hi Handy,

I understand that you or the developers want me to change the code to your standard way on all pages.

But I'd like to stress that this problem happens throughout our application, not only on the pages that are "not implemented proper"; it happens on all pages where WebGrid posts back.

If in your post above you meant InitializeSelfReferenceDataSource, not InitializeDataSource: I understand that you think it is not related and a different issue. But it is related. This part works well otherwise and crashes this way, reproducible, when the crash condition occurs. And why should dt.Merge crash if the database returns correct results? So this can only happen if there is an internal problem with the WebGrid state.

Please also understand that there is no timeout. The answer comes immediately, there is absolutely no delay involved.

So could you please investigate again?

Thanks,

Eric

Hello Eric,

Ok, I will to let our developer teams know about this situation. But regarding the crash server, there would be some possibilities that caused this error. Can you give the screenshot of the unhandled error (not stack race)?

Regards,
Handy

Hi Handy,

I don't understand what you need here. I don't have any additional information available. I have no access to the server (but could request something) and at the time it happened I could log all HTTP communication to the server. For the mentioned crash, I can see that after the WebGrid request to the server goes out, an error page with status 500 gets sent back. The WebGrid detects this answer as illegal answer from the server and runs an OnUnhandledError event, so that the client gets redirected to a general error page. The user only sees this general error page. From the HTTP log I could extract the original error message with the status 500 and the stack trace. The error message itself was also listed in my post, so there's no other information available.

If you need anything else, please let me know how I should obtain this information.

Maybe you meant that you want a screenshot of the usual unhandled error dialogs. But as mentioned earlier, we don't have these dialogs anymore, because we catch unhandled errors in our code and redirect to a custom (general) error page if this happens.

Thanks,

Eric

Hello Eric,

Ok, I understand. But when the error raised, please capture a screenshot about the dialog error. We might be need this.

Regards,
Handy

Hi Handy,

You still misunderstood me. If you mean the usual "unhandled error" dialog: We catch the client side event OnUnhandledError, so this dialog doesn't appear anymore. Hence I cannot create a screenshot of a non-existent dialog.

The parameters passed to the OnUnhandledError event are as follows:

• action: LoadSelfRefChild
• errorString: (the full HTML error page)
• gridId: grid that caused this
• lastRequestObject: some object (no details known)

This is only for the case where I have the crash I mentioned. In the other case (zero-length response), only the gridId holds a value, the rest is empty.

Eric

Hi Eric,

Ok, I understand about your issue. Is it possible for us to schedule remote in your server? 
As you said, this happens randomly. Can you ensure when the possiblities the crash would happen again?
Perhaps, If we can find the correct time, we can investigate the issue by remoting to your server (debug).

Regards,
Handy 

Hi Handy,

No, this does not happen on specific times. So we cannot predict when it will happen the next time.

I have no access to this production server and will not get access - much less someone from outside our company. If you need to debug, then maybe you can tell me what to monitor and I can request this monitoring or add debug output or something similar.

Let me know what you need to look at.

Regards, Eric

Hello Eric,

I see. So you can also predict what's the time. I need you to put breakpoint in each life cycle and run it step by step (F10) and let me know in what code/event, it return the error.

Regards,
Handy

Hi Handy,

No. I can NOT predict when it will happen the next time.

I also can NOT set breakpoints nor debug on that server. But I can add additional logging into text files or the database if required. Let me know what exactly you want to get logged.

Eric

Hi Eric,

Actually, It is very hard to investigate this issue. We need to able to replicate the issue first. Without this, it seems not possible to resolve the issue. We would like to try our best, to investigating the issue based on your current detail. Btw, does your server use something like "AutoLoadBalancing"?

Regards,
Handy

Hi,

I know this is a difficult issue. I fully understand that you want to replicate this. Without replication it is extremely difficult to debug, as you cannot investigate locally, I know.

But I also know that it will currently not be possible to replicate this on your side, so we should try to get all information possible from that server when the problem reappears.

I don't know what you mean with "AutoLoadBalancing". There's only one server (hence no load balancer server) and it's a Windows 2000 Advanced Server (with the old IIS), so I assume there's no such feature built-in.

If you want me to build additional logging into the application, let me know what you need to get logged.

Regards,

Eric

any update?

Hello Eric,

There is no update response from our developer teams. They are still discussing what might causing this issue. I am very sorry about this. But we are very difficult to discuss the issue due to lack of resources. At least, we need to replicate the issue first.

Regards,
Handy

Handy,

Any update yet?

Eric

ping

Hello Eric,

I am sorry. Unfortunately, there are no updates from our developer since we are still unable to replicate the issue.

Regards,
Handy

Hi Handy,

But I assume you are still working on it, right?

Please let me know if I can help anything. And please keep me updated.

Thanks,

Eric

ping

Hi Eric,

Yes, but currently we are also stuck because we still unsucessful to replicate the issue.

Regards,
Handy

So how will it go on with this bug? As you cannot replicate it yet, does this mean you will not try any longer to investigate and just not fix it?

Hello Eric,

We don't have any update or progress in this situation. I hope your understand that it's very hard to investigate without replicate the issue.

Regards,
Handy

I fully understand that it's difficult. That's why I offered to add logging or whatever.

But what I understood is that under current circumstances you are not interested in getting this fixed. Can you confirm that you won't fix this issue?

Hi,

I do understand about that. But as you said, the issue is randomly happened. There is no guarantee if I login, I can see the issue. If it still runs well when I login, I still could not do any progress about that.

Also, We never said that we refuse to fix it. It's just we need to replicate the issue first.

Regards,
Handy

I don't understand what you mean.

We both know you won't be able to reproduce the issue - ever. (That's why I offered help to debug / log.)

Hello,

Unfortunately, the resources are not enough. First, the log does not lead us to further investigation.
The information is not enough. Last, even we can debug it, we need to debug at the time the error/crash happened. If not, we don't have the information what is exactly cause the error.
If we are able to replicate the issue and know what cause the issue, we will fix it.

Regards,
Handy

You know that you can never test on a production system. And reproducing this is also not possible right now as you know.

So the only thing we can do is to add some logging to find out more details (which might lead to a reproduction scenario or whatever). But you never told me what you need.

I understand that this bug is not very important for you, as this happens currently only for us and only randomly every few weeks and on an old server - together with your limited resources. But it is still a very drastic bug and might still exist on any newer server for any client you have.

So please let me know how to go on. If you don't want to fix it, please tell us this clearly too. Just letting us wait and telling things about reproduction is no option.

Did this bug ever get resolved?

Hi Frank! No, it never got resolved. But we moved away from that Windows 2000 server to a "new" platform (IIS6) a few months ago and there I don't remember having any problems with this. The new environment has other issues, but not this one.