COM Surrogate Error?

[rlawrence]

I'm running a Windows 2003 server with IIS6 and VFP7. Some of the regulars here may recall that I have a VFP7 COM-based web application running in this environment. The application is installed as a COM+ component--primarily for security purposes.

With increasing frequency, I am getting a "COM Surrogate Error" notice when I log into the server. I'm given the option to send the information to Microsoft or ignore it.

The error doesn't seem to affect my web sites. I'm assuming that IIS simply restarts DLLHost the next time it receives a request for one of our web sites. But, I've had a couple of situations lately where IIS seems to have shut down. I truly don't know whether these problems are related, but it seems like a good idea to eliminate this problem in hopes of addressing the other.

Checking the event log, I get the following application error entry repeatedly:

Event Type:	Information
Event Source:	Application Error
Event Category:	(100)
Event ID:	1004
Date:		11/7/2014
Time:		7:12:58 AM
User:		N/A
Computer:	WINSERVER
Description:
Reporting queued error: faulting application dllhost.exe, version 5.2.3790.3959, faulting module vfp7t.dll, version 7.0.0.9465, fault address 0x0011cb3f.

For more information, see Help and Support Center at [URL unfurl="true"]http://go.microsoft.com/fwlink/events.asp.[/URL]
Data:
0000: 41 70 70 6c 69 63 61 74   Applicat
0008: 69 6f 6e 20 46 61 69 6c   ion Fail
0010: 75 72 65 20 20 64 6c 6c   ure  dll
0018: 68 6f 73 74 2e 65 78 65   host.exe
0020: 20 35 2e 32 2e 33 37 39    5.2.379
0028: 30 2e 33 39 35 39 20 69   0.3959 i
0030: 6e 20 76 66 70 37 74 2e   n vfp7t.
0038: 64 6c 6c 20 37 2e 30 2e   dll 7.0.
0040: 30 2e 39 34 36 35 20 61   0.9465 a
0048: 74 20 6f 66 66 73 65 74   t offset
0050: 20 30 30 31 31 63 62 33    0011cb3
0058: 66                        f

This is certainly out of my area of expertise. Doing the usual internet search hasn't turned up anything useful. Can anyone here point me in the right direction for understanding this problem?

Thanks in advance,

Ron

 

[Olaf Doschke]

In the end it points to a C5 error occurring in the vfp runtime, perhaps.

COM Surrogate is the dllhost.exe, which hosts the COM Server DLL you most probably have started. And this in turn uses the vfp7t.dll Runtime für Multithreaded COM Server DLLs.

It might be an issue of too many concurrrent sessions, overload. Anyway, I'd look into any error log you have about your VFP7 COM Server.

Bye, Olaf.

 

[rlawrence]

Hi Olaf,

Thanks again for your help. O.K. I must admit that my eyes gloss over when I see something like this. The C5 error is simply an unspecified error, right? How did you deduce a C5 error from the information I posted above?

Whatever is causing this doesn't seem to make its way to my error log (which includes any VFP errors). It's vfp7t.dll that is failing, but I haven't a clue to finding out why.

I suspect that your assessment of "Too many concurrent sessions" is on the right track; but that's really Windows running out of some other resource, right? Where would I be likely to find information about why--if not in the event logs?

Also, we're not talking about a heavy traffic load on these web sites. There are more hits from spiders than users. I know these spider hits will still invoke the application. I could use a good strategy for discerning which spiders are friendly and which are not.

Ron

 

[Olaf Doschke]

Well, if there is an error reported about the runtime it's rather pointing to a c5 than a normal error, as the runtime is not crashing with any normal VFP error. I said perhaps.
If you even don't find any vfp7.err file with C5 errors - that's where those go because the runtime itself fails and so even the error handler can't run - if you don't find this, then there is some error on the outside. Could also be any flaky hardware, but then you would most probably not only find errors about the vfp7t.dll

Are you logging errors? If so how? A normal ON ERROR routine is not the way to go, if you program a COM Server for IIS. Take a look into "Visual FoxPro and Advanced COM"
In it's Error Handling paragraph you find more about error handling within a VFP COM DLL.

Bye, Olaf.