IIS 6.0 - Memory problem in "Worker process isolation mode"

The COM component in question was written in VB6 by me.

Where should I look to find information on what makes a COM component
incompatible with IIS6 Worker Process Isolation Mode?

The computer where IIS6 is installed is a test box that only has 128 MB of
physical RAM, so I suppose that I could be bumping up against some sort of
limit there. I won't be able to physically get access to the computer until
Monday - I'll look at "free" RAM at that point.


"David Wang [Msft]" <someone.TakeThisOut@online.microsoft.com> wrote in message
news:OOliHgvSEHA.1732@TK2MSFTNGP09.phx.gbl...
 > I do not think the issue has anything to do with availability of memory.
 > IIS does not place memory restrictions in either mode; it just uses RAM
like
 > any other process. How much physical RAM does the server have, and how
much
 > does Task Manager report as "free" when you get the "out of memory" error?
 >
 > I suspect the problem is that your COM components is incompatible with
IIS6
 > Worker Process Isolation Mode, and one of the errors got translated as
"out
 > of memory". Since this is an application-level error, it won't get logged
 > to the event log by IIS.
 >
 > Best thing to do is to contact the COM component vendor regarding its
 > support of IIS6. If your COM components are incompatible with IIS6 worker
 > process isolation model, there's not a whole lot that can be done other
than
 > to update the COM component.
 >
 > --
 > //David
 > IIS
 > This posting is provided "AS IS" with no warranties, and confers no
rights.
 > //<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: IIS 6.0 - Memory problem in "Worker process isolation mode" 

Hello Bob,

Just a kind reminding, please double check 'retain in memory' and
'unattended execution' switches are turned on when you compile the
dll:
264957 PRB: Visual Basic DLL Has Memory Leaks and Crashes in COM+ If
'Retain In
http://support.microsoft.com/?id=264957

Best regards,

WenJun Zhang
Microsoft Online Support
This posting is provided "AS IS" with no warranties, and confers no
rights.
Get Secure! - www.microsoft.com/security
 >> Stay informed about: IIS 6.0 - Memory problem in "Worker process isolation mode" 

Hi Bob,

Have you got any progress or findings during the test?

Best regards,

WenJun Zhang
Microsoft Online Support
This posting is provided "AS IS" with no warranties, and confers no
rights.
Get Secure! - www.microsoft.com/security
 >> Stay informed about: IIS 6.0 - Memory problem in "Worker process isolation mode" 

I have more information now.

I tried my application on a different IIS6 box, this one had 750MB of free
RAM as reported by Task Manager (1 Gig total RAM), and I got the same "Out
of Memory" error as before. Whatever the problem is, it probably is not
related to the amount of physical RAM on the server.

Regarding the VB6 DLLs I'm using, many of them do have 'retain in memory'
and 'unattended execution' turned ON. However, there are a couple of
ActiveX DLL projects where I cannot turn these options ON because the
project contains a form. The form is never used in the context of my ASP
application, but because the DLL is also used with a WinForms version of the
application which does use the form, the form must be contained in the DLL.

Knowledgebase article 833891 recommends putting W3wp.exe.cfg in the
%windir%\system32\inetsrv folder. I tried that and it made no difference -
I still got the "Out of Memory" error in my DLL.

If a form is contained in an ActiveX DLL, and W3wp.exe.cfg is used to turn
ON 'retain in memory' and 'unattended execution', then are these options
ACTUALLY turned ON?

Why is it that my ASP application, which has been running successfully on
IIS 4 through 5.1, even though some of my ActiveX DLLs do not have 'retain
in memory' and 'unattended execution' turned ON, is unable to run on IIS6 in
"worker process isolation mode"? Is this problem due solely to the fact
that some ActiveX DLLs do not have 'retain in memory' and 'unattended
execution' turned ON?


""WenJun Zhang[msft]"" <v-wzhang.TakeThisOut@online.microsoft.com> wrote in message
news:TOwcL1DTEHA.2316@cpmsftngxa10.phx.gbl...
 > Hello Bob,
 >
 > Just a kind reminding, please double check 'retain in memory' and
 > 'unattended execution' switches are turned on when you compile the
 > dll:
 > 264957 PRB: Visual Basic DLL Has Memory Leaks and Crashes in COM+ If
 > 'Retain In
<font color=purple> > <a style='text-decoration: underline;' href="http://support.microsoft.com/?id=264957</font" target="_blank">http://support.microsoft.com/?id=264957</font</a>>
 >
 > Best regards,
 >
 > WenJun Zhang
 > Microsoft Online Support
 > This posting is provided "AS IS" with no warranties, and confers no
 > rights.
<font color=purple> > Get Secure! - <a style='text-decoration: underline;' href="http://www.microsoft.com/security</font" target="_blank">www.microsoft.com/security</font</a>>
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: IIS 6.0 - Memory problem in "Worker process isolation mode" 

Here's another question. Is there any harm in turning ON 'retain in memory'
and 'unattended execution' for an ActiveX DLL that is used as part of a VB6
WinForms application?

"Bob" <bob.pq DeleteThis @nospam.nospam> wrote in message
news:uRdjaTkTEHA.3512@TK2MSFTNGP12.phx.gbl...
 > I have more information now.
 >
 > I tried my application on a different IIS6 box, this one had 750MB of free
 > RAM as reported by Task Manager (1 Gig total RAM), and I got the same "Out
 > of Memory" error as before. Whatever the problem is, it probably is not
 > related to the amount of physical RAM on the server.
 >
 > Regarding the VB6 DLLs I'm using, many of them do have 'retain in memory'
 > and 'unattended execution' turned ON. However, there are a couple of
 > ActiveX DLL projects where I cannot turn these options ON because the
 > project contains a form. The form is never used in the context of my ASP
 > application, but because the DLL is also used with a WinForms version of
the
 > application which does use the form, the form must be contained in the
DLL.
 >
 > Knowledgebase article 833891 recommends putting W3wp.exe.cfg in the
 > %windir%\system32\inetsrv folder. I tried that and it made no
difference -
 > I still got the "Out of Memory" error in my DLL.
 >
 > If a form is contained in an ActiveX DLL, and W3wp.exe.cfg is used to turn
 > ON 'retain in memory' and 'unattended execution', then are these options
 > ACTUALLY turned ON?
 >
 > Why is it that my ASP application, which has been running successfully on
 > IIS 4 through 5.1, even though some of my ActiveX DLLs do not have 'retain
 > in memory' and 'unattended execution' turned ON, is unable to run on IIS6
in
 > "worker process isolation mode"? Is this problem due solely to the fact
 > that some ActiveX DLLs do not have 'retain in memory' and 'unattended
 > execution' turned ON?
 >
 >
 > ""WenJun Zhang[msft]"" <v-wzhang DeleteThis @online.microsoft.com> wrote in message
 > news:TOwcL1DTEHA.2316@cpmsftngxa10.phx.gbl...
  > > Hello Bob,
  > >
  > > Just a kind reminding, please double check 'retain in memory' and
  > > 'unattended execution' switches are turned on when you compile the
  > > dll:
  > > 264957 PRB: Visual Basic DLL Has Memory Leaks and Crashes in COM+ If
  > > 'Retain In
<font color=green>  > > <a style='text-decoration: underline;' href="http://support.microsoft.com/?id=264957</font" target="_blank">http://support.microsoft.com/?id=264957</font</a>>
  > >
  > > Best regards,
  > >
  > > WenJun Zhang
  > > Microsoft Online Support
  > > This posting is provided "AS IS" with no warranties, and confers no
  > > rights.
<font color=green>  > > Get Secure! - <a style='text-decoration: underline;' href="http://www.microsoft.com/security</font" target="_blank">www.microsoft.com/security</font</a>>
  > >
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: IIS 6.0 - Memory problem in "Worker process isolation mode" 

If a form is contained in an ActiveX DLL, and W3wp.exe.cfg is used to
turn ON 'retain in memory' and 'unattended execution', then are these
options ACTUALLY turned ON?
[WenJun]
Turning on the two switches means w3wp.exe will not unload the dlls
as soon as current job is finished. They will remain in memory for
the next time beng callled. Have you restarted IIS after making the
w3wp.exe.cfg?

Why is it that my ASP application, which has been running
successfully on IIS 4 through 5.1, even though some of my ActiveX
DLLs do not have 'retain in memory' and 'unattended execution' turned
ON, is unable to run on IIS6 in "worker process isolation mode"? Is
this problem due solely to the fact that some ActiveX DLLs do not
have 'retain in memory' and 'unattended execution' turned ON?
[WenJun]
The most familiar symptom on IIS of incorrectly complied VB
dll(without the two switches) is memory leak, which generally isn't a
rapid failure but can cause crash or hang after memory overflow the
limitation. Therefore it's just a possibility. If the dlls can work
properly on your IIS5.x server without any problem and the 'out of
memory' error occurs initially on IIS6 WPI, just as David mentioned,
it most likes the dll is incompatible with IIS6 worker process mode.

Best regards,

WenJun Zhang
Microsoft Online Support
This posting is provided "AS IS" with no warranties, and confers no
rights.
Get Secure! - www.microsoft.com/security
 >> Stay informed about: IIS 6.0 - Memory problem in "Worker process isolation mode" 

I believe there isn't serious impact. With these switches turning on,
dlls will not be released at runtime but when the WinForm application
is terminated.

Best regards,

WenJun Zhang
Microsoft Online Support
This posting is provided "AS IS" with no warranties, and confers no
rights.
Get Secure! - www.microsoft.com/security
 >> Stay informed about: IIS 6.0 - Memory problem in "Worker process isolation mode" 

Yes, I rebooted the server after installing w3wp.exe.cfg, but still got the
"Out of Memory" error.

You say that it is likely that "the dll is incompatible with IIS6 worker
process mode". What things can make the DLL incompatible with WPM? Is it
because the DLL contains forms and thus cannot have 'retain in memory' and
'unattended execution' turned ON? Or are there other things about a DLL
that can make it incompatible with WPM? This seems like something that a
knowledgebase article should talk about.


""WenJun Zhang[msft]"" <v-wzhang DeleteThis @online.microsoft.com> wrote in message
news:846Ut6rTEHA.3468@cpmsftngxa10.phx.gbl...
 > If a form is contained in an ActiveX DLL, and W3wp.exe.cfg is used to
 > turn ON 'retain in memory' and 'unattended execution', then are these
 > options ACTUALLY turned ON?
 > [WenJun]
 > Turning on the two switches means w3wp.exe will not unload the dlls
 > as soon as current job is finished. They will remain in memory for
 > the next time beng callled. Have you restarted IIS after making the
 > w3wp.exe.cfg?
 >
 > Why is it that my ASP application, which has been running
 > successfully on IIS 4 through 5.1, even though some of my ActiveX
 > DLLs do not have 'retain in memory' and 'unattended execution' turned
 > ON, is unable to run on IIS6 in "worker process isolation mode"? Is
 > this problem due solely to the fact that some ActiveX DLLs do not
 > have 'retain in memory' and 'unattended execution' turned ON?
 > [WenJun]
 > The most familiar symptom on IIS of incorrectly complied VB
 > dll(without the two switches) is memory leak, which generally isn't a
 > rapid failure but can cause crash or hang after memory overflow the
 > limitation. Therefore it's just a possibility. If the dlls can work
 > properly on your IIS5.x server without any problem and the 'out of
 > memory' error occurs initially on IIS6 WPI, just as David mentioned,
 > it most likes the dll is incompatible with IIS6 worker process mode.
 >
 > Best regards,
 >
 > WenJun Zhang
 > Microsoft Online Support
 > This posting is provided "AS IS" with no warranties, and confers no
 > rights.
<font color=purple> > Get Secure! - <a style='text-decoration: underline;' href="http://www.microsoft.com/security</font" target="_blank">www.microsoft.com/security</font</a>>
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: IIS 6.0 - Memory problem in "Worker process isolation mode" 

I'm having the same problem. ActiveX DLLs that worked on a
Windows2000 IIS 5.0 platform no longer work on IIS 6.0 Windows2003
platform. I get an Out of Memory error.

The DLLs where created with "Retain in Memory" and "Unattended
Execution" set to true. I've run an ISSDump to verify that the DLLs
where configured correctly. I even created the W3wp.exe.cfg file and
set the [Options] as per the KB 833891. No success.

Have you or anyone else been successful in resolving the problem?
 >> Stay informed about: IIS 6.0 - Memory problem in "Worker process isolation mode" 

One of the reasons why the VB ActiveX DLLs worked on IIS4 through 5.1 but
not on 6 is because of the VB Runtime having special hardcoded hacks to look
for process names of IIS4 through 5.1 and applying "retain in memory" and
"unattended execution" automatically. In other words, the user may have had
bad VB ActiveX DLLs, but he was transparently relying on the system to fix
them.

w3wp.exe for IIS6 is an unknown process name for any existing VB Runtime,
hence it doesn't apply the hacks, which exposes problems in the user's
ActiveX DLLs. I know this issue has come up a long time ago during IIS6
development and the VB team "fixed" their hack to recognize IIS6, but I do
not know if you're using that updated runtime.

One of the reasons that the hack exists is because EVERY VB DLL has to have
those options checked, or else you risk having issues. Often, VB controls
are built on other VB controls which you do not control and cannot fix -- so
the VB Runtime hack is a viable solution to that problem -- but it also
binds you to legacy.

If you try running IIS6 in IIS5 Compatibility Mode and everything magically
starts working, then I suspect you had broken code and you're relying on the
VB Runtime hack, even back on IIS4/5/5.1 -- so you need to get the updated
VB Runtime to eliminate that as a blocker on IIS6. There isn't anything
"wrong" with IIS6 -- the fundamental problem is within your code; the
implicit work-arounds that you're relying on just wasn't there, and that's
not exactly an IIS6 problem.

--
//David
IIS
This posting is provided "AS IS" with no warranties, and confers no rights.
//
""WenJun Zhang[msft]"" <v-wzhang.TakeThisOut@online.microsoft.com> wrote in message
news:846Ut6rTEHA.3468@cpmsftngxa10.phx.gbl...
If a form is contained in an ActiveX DLL, and W3wp.exe.cfg is used to
turn ON 'retain in memory' and 'unattended execution', then are these
options ACTUALLY turned ON?
[WenJun]
Turning on the two switches means w3wp.exe will not unload the dlls
as soon as current job is finished. They will remain in memory for
the next time beng callled. Have you restarted IIS after making the
w3wp.exe.cfg?

Why is it that my ASP application, which has been running
successfully on IIS 4 through 5.1, even though some of my ActiveX
DLLs do not have 'retain in memory' and 'unattended execution' turned
ON, is unable to run on IIS6 in "worker process isolation mode"? Is
this problem due solely to the fact that some ActiveX DLLs do not
have 'retain in memory' and 'unattended execution' turned ON?
[WenJun]
The most familiar symptom on IIS of incorrectly complied VB
dll(without the two switches) is memory leak, which generally isn't a
rapid failure but can cause crash or hang after memory overflow the
limitation. Therefore it's just a possibility. If the dlls can work
properly on your IIS5.x server without any problem and the 'out of
memory' error occurs initially on IIS6 WPI, just as David mentioned,
it most likes the dll is incompatible with IIS6 worker process mode.

Best regards,

WenJun Zhang
Microsoft Online Support
This posting is provided "AS IS" with no warranties, and confers no
rights.
Get Secure! - www.microsoft.com/security
 >> Stay informed about: IIS 6.0 - Memory problem in "Worker process isolation mode"