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  1. #1
    Join Date
    Nov 2002

    Unanswered: strange connectivity problem...

    Here's a strange one...

    I'm supporting two similar 3 tier apps for a custumer using the same middle tier component and basic architecture. IIS web app uses COM+ to communicate with the middle tier component. The middle tier component uses ODBC to link to the SQL Server 2000 backend. All servers are Windows 2000.

    One of the two web apps has a separate server for the middle tier - an application server. The other web app has the middle tier application server code on the database server. Otherwise, the two apps are pretty much the same. **The problem occurs on the server where the application server code is on the same server as the database**.

    **The problem seems to occur when I open up Enterprise Manager on the database server and leave it open for quite a while**. What happens is that the web application as viewed from a browser on the Internet will suddenly fail as follows:-

    Event Type: Error
    Event Source: Unipower Retail.UPREvent
    Event Category: None
    Event ID: 0
    Date: 27/11/2002
    Time: 10:04:22
    User: N/A
    Computer: {removed for security}
    The description for Event ID ( 0 ) in Source ( Unipower Retail.UPREvent ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. The following information is part of the event: Log entry, "27-11-2002","10:04:22",2,0,0,"XAbcBase",'<Error class = "XError" >\n
    <Error class = "XError" >\n
    HRESULT of 80020009, error description of (<Error class = "XError" >\n
    <Error class = "XError" >\n
    Could not create DAServer object. Result was (800706ba). at line 1049 of file D:\SourceFiles\Retail5\UPRBusinessObjects\UPRObjec t.cpp\n
    </Error><Activity name="CUPRObject::Load()" action="Create DAServer Instance" />\n
    </Error> at line 264 of file D:\SourceFiles\Retail5\UPRBusinessObjects\UPRObjec t.cpp\n
    </Error><Activity name="CUPRObject::Invoke" action="Invoke" />\n

    This has been happening a while and there definitely seems to be a pattern associated with me having Enterprise Manager open on the database server for a good while. I've obvioiusly been talking to the software developer but their techie can't explain why it is happening.

    The problem can be reproduced exactly by taking the database 'off-line'. I'm not sure why the front-end web page should error when it is communicating with the middle tier. It is as if having Enterprise Manager open can sometimes trigger a COM+ resource conflict between the middle tier app and Enterprise Manager - Enterprise Manager wins! This might explain why the problem does not occur when the middle tier app is on its own separate server?

    Can anyone suggest what this problem is or a way to pin it down to exactly what is causing it? I will be carrying out some connectivity tests soon to see if ADO and ODBC connections are success when COM+ is not. I will also be running these tests from different servers to see if there are any firewall issues affecting this. However, maybe someone else has come across something similar and this will save me a lot of time groping around for the answer?

    Thanks in advance.

    Clive Richardson

  2. #2
    Join Date
    Oct 2002

    Re: strange connectivity problem...

    **The problem seems to occur when I open up Enterprise Manager on the database server and leave it open for quite a while**.

    EM* Enterprise Manager, can be very resource intensive.

    Whenever possible, it is safest and arguably therefore best, to only run EM on a client (an administrative workstation) and not at the console of production servers. In particular, it is an especially good idea to avoid "leaving it open for quite a while" at the console (including. terminal services connections) of any production server(s).

    *EM, affectionately a.k.a. "Enterprise Mangler".
    Last edited by DBA; 01-06-03 at 14:27.

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