ASP.NET using COM+ is deadlocking

[Juan Dent]

Hi,

An ASP.NET 2003 application that uses VB6 COM+ components, works fine with
3-6 users, but gets "frozen" when accesed by 12-or more users.

At some point an error message similar to "OOA: Out of Apartments" was
displayed. This was reported to me, I did not see it.

We also got a warning/error "Component using serialization may cause
deadlock".

This used to work fine on NT4, but Windows 2000 breaks it.

Any ideas?
My own are:
the COM+ components being all STA are not scallable
the thread pool for STA in Windows 2000 and later is 7*NumberOfProcessors
maybe the deadlock is activity related, i.e. usage of shared components,
which is worsened by the higher concurrency

--
Thanks in advance,

Juan Dent, M.Sc.

[KJ]

While not a specific answer to your post, the following article
contains some interesting information regarding the situation you are
in:

http://msdn.microsoft.com/library/de...s_MTStoCOM.asp

Juan Dent wrote:

Hi,

An ASP.NET 2003 application that uses VB6 COM+ components, works fine with
3-6 users, but gets "frozen" when accesed by 12-or more users.

At some point an error message similar to "OOA: Out of Apartments" was
displayed. This was reported to me, I did not see it.

We also got a warning/error "Component using serialization may cause
deadlock".

This used to work fine on NT4, but Windows 2000 breaks it.

Any ideas?
My own are:
the COM+ components being all STA are not scallable
the thread pool for STA in Windows 2000 and later is 7*NumberOfProcessors
maybe the deadlock is activity related, i.e. usage of shared components,
which is worsened by the higher concurrency

--
Thanks in advance,

Juan Dent, M.Sc.

[Walter Wang [MSFT]]

Hi Juan,

As the article suggested, if applications migrated from MTS to COM+ and
client is sharing references to an "Apartment" instance, the
synchronization deadlocks will become more magnified under COM+. So it's
recommended avoid sharing reference to any objects, especially those marked
as "Apartment."

Of course I understand that changing code may have great impact and not
practical sometimes. So another possible workaround is to emulate MTS
behavior as described in following kB:

#Registry key for tuning COM+ thread and activity
http://support.microsoft.com/kb/q303071/

Please tell me the result of this suggestion and we can further discussion
what to do next.

Sincerely,
Walter Wang (wa****@online.microsoft.com, remove 'online.')
Microsoft Online Community Support

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