4 replies

Last post Jun 27, 2013 09:41 AM by mvolo

  • IIS Hangs

    Apr 19, 2009 10:01 PM|ankit.g|LINK


     We are using IIS 6.0 on the MS 2003 server SP2. Application uses oracle database and the client version installed on the server is Oracle

    We are experience a performance issue where the site randomly hangs and we are not even able to take the server remotely  to debug the issue. We installed the DebugDiag tool to find the root cause. Please find below  the log from the DebugDiag.

    Request your help in resolving the issue


    The following threads in w3wp.exe__DefaultAppPool__PID__3004__Date__04_17_2009__Time_04_54_08PM__796__IIS_COM+ Hang Dump.dmp are making a database operation using ADO.

    The call to MSADO15!CCOMMAND::EXECUTE originated from vbscript!CatchIDispatchInvoke+46

    ( 33 44 46 57 )

    5.63% of threads blocked

      Warning Detected possible blocking or leaked critical section at 0x04aaa268 owned by thread 66 in w3wp.exe__DefaultAppPool__PID__3004__Date__04_17_2009__Time_04_54_08PM__796__IIS_COM+ Hang Dump.dmp

    Impact of this lock

    4.23% of threads blocked

    (Threads 56 58 70)

    The following functions are trying to enter this critical section

    The following module(s) are involved with this critical section
    D:\oracle\product\10.2.0\client_1\BIN\oracore10.dll from Oracle Corporation
    The following vendors were identified for follow up based on root cause analysis

    Oracle Corporation
    Please follow up with the vendors identified above Consider the following approach to determine root cause for this critical section problem:
    1. Enable 'lock checks' in Application Verifier
      • Download Application Verifier from the following URL:
             Microsoft Application Verifier
      • Enable 'lock checks' for this process by running the following command:
             Appverif.exe -enable locks -for w3wp.exe
      • See the following document for more information on Application Verifier:
             Testing Applications with AppVerifier
    2. Use a DebugDiag crash rule to monitor the application for exceptions
      Warning The following threads in w3wp.exe__DefaultAppPool__PID__3004__Date__04_17_2009__Time_04_54_08PM__796__IIS_COM+ Hang Dump.dmp are incomplete and also has/have an invalid Thread Environment Block pointer. As a result, the information reported is most likely inaccurate.

    ( 48 )

    1.41% of threads blocked

    If call stacks relevant to the problem could not be accurately analyzed due to bad TEB information then a new dump may need to be obtained.
      Warning 1 client connection(s) in w3wp.exe__DefaultAppPool__PID__3004__Date__04_17_2009__Time_04_54_08PM__796__IIS_COM+ Hang Dump.dmp have been executing a request for more than 90 seconds. Please see the Client Connections section of this report for more detailed information about the connection(s).

  • Re: IIS Hangs

    Apr 20, 2009 10:17 AM|ma_khan|LINK



    We are experience a performance issue where the site randomly hangs and we are not even able to take the server remotely  to debug the issue.

    You are not able to take control remotely by that we can say it is the server that is hanging rather than just the site. Next, by the analysis report that you have given ...a lot of it hints at oracore10.dll

    Did you check that ?

    Seems like your threads are in wait state as they are unable to run queries.... 

  • Re: IIS Hangs

    Apr 20, 2009 11:26 PM|ankit.g|LINK

    Thanks ma_khan for your quick help. Actually I am not sure how to troubleshoot the oracore10.dll. Is it the problem with the oracle client on the server? Because when we execute the same queries from PL/SQL we get the results in less than 0.04 seconds.

     It will be really great if you can please let me know how the issue related to oracore10.dll can be tackled.

     All the valuble inputs are well appreciated.



  • Re: IIS Hangs

    Apr 21, 2009 10:52 AM|ma_khan|LINK

    Are these pages DB intensive... I mean are you trying to get large amount of data ... Also you might want to check if there is good connectivity between the IIS server and the DB Server ...

    That is all I can tell with the data we have ? is your oracle client patched...

  • Re: IIS Hangs

    Jun 27, 2013 09:41 AM|mvolo|LINK

    Is this an ASP.NET application? Usually hangs happen due to request threads blocking on database or network calls, and exhausting available threads in the threadpool.  If you can catch the hang live, you should be able to snapshot the thread stacks in the worker process to identify where they are hanging.  Past that, you'd have to use the debugger and do some analysis.

    DebugDiag mostly focuses on synchronization deadlocks, which we see rarely these days.

    We also recently added automatic hang troubleshooting to LeanSentry, see The holy grail: Automatically diagnose IIS and ASP.NET website hangs. This will diagnose most of the common hang causes for IIS/ASP.NET applications.

    Mike Volodarsky
    CTO at LeanSentry
    Former IIS/ASP.NET PM