By default there are a series of timeouts that are set that could be affecting 
what you are seeing. Adjusting the timeouts completely depends on the behavior 
of the users.

 

For example as a developer working on a map you may want to significantly 
increase the timeout settings to allow connections to last for 20 min or more 
whereas a user on the production server may spend no more than 5 or 10 min 
querying a map so holding connections for too long is a waste or can 
potentially not free up resources for other users.

 

Most of the default settings hold a session for about 20 min. So after you let 
your map sit for 20 min you will have to refresh it. However below the main 
timeout settings there is Connection Pooling taking place within FDO. These 
connections are held for 10 min (600 seconds) and then released. You may want 
to try and up this to 20 min to match the other timeouts. However in testing we 
have never seen the link failure error that I am aware of.

 

A communication link failure seems more like something external to FDO has 
dropped the connection rather than FDO dropping the connection. FDO is trying 
to use a connection that is no longer valid for some reason. Is there a proxy 
server or firewall or router in between your MapGuide server and your database 
server that could be dropping the connection? I’ve done some Google searches 
and one possibility is that your DSN has connection pooling enabled and it may 
be that the connection is dropped by SQLServer by the time you try to reuse it. 
It’s not clear yet if it’s actually a MapGuide bug.

 

The Google searches weren’t very informative. You might try to search msdn 
instead.

 

Dave

 

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Thursday, July 05, 2007 11:05 AM
To: MapGuide Users Mail List
Subject: RE: [mapguide-users] ODBC Point features failure

 


Hi Dave, thanks for the responses... 

I didn't know about the error log - there are indeed error messages like the 
following: 

<2007-07-05T13:54:45>                         fac 
 Error: Failed to stylize layer: Points 
        An exception occurred in FDO component. 
        RDBMS: [Microsoft][ODBC SQL Server Driver]Communication link failure 
 StackTrace: 
  - MgStylizationUtil.StylizeLayers line 923 file 
c:\build_bond_area\mapguide_open_source_v1.2\build_18.1\mgdev\server\src\services\mapping\StylizationUtil.cpp
        Failed to stylize layer: Points 
An exception occurred in FDO component. 
RDBMS: [Microsoft][ODBC SQL Server Driver]Communication link failure 

Why would there be a Communications link failure?  We have lots of processes 
which communicate to that particular database continually.   It seems that 
something inside the FDO provider times out and it thinks it can no longer 
access SQL Server.   

If I restart the mapguide service and re-open the site, it initially works.  If 
I let it just sit there for a few minutes, without doing any zooming or panning 
or clicking, then when I try to zoom after that, the points disappear - and 
that error message above is in the error log.   So it seems that something in 
the FDO provider is timing out - it is allowing the connection to timeout 
perhaps and it doesn't re-establish it? 

Thanks for your help, 

Ian Elsinga




"Dave Wilson" <[EMAIL PROTECTED]> 
Sent by: [EMAIL PROTECTED] 

07/05/2007 11:36 AM 

Please respond to
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RE: [mapguide-users] ODBC Point features failure

 

                




Are there any errors logged in the server error log? It seems to me something 
is causing the provider to die? Usually there is at least 1 error logged before 
something like this can happen. 
  
What coordinate system is your data in and what coordinate system is your map 
in? 
  
Have you tried using the DWF Viewer/Autodesk Design Review? I’m curious if it’s 
the data or something in the viewer behavior. 
  
Regards, 
Dave 
  
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Thursday, July 05, 2007 6:25 AM
To: MapGuide Users Mail List
Cc: MapGuide Users Mail List; [EMAIL PROTECTED]
Subject: RE: [mapguide-users] ODBC Point features failure 
  

I noticed that when it stops working, there are no more SQL statements being 
sent to the database.  (Discovered by using SQL Profiler).   

Ian Elsinga
Senior Client/Server Application Developer
First Atlantic Commerce
Bermuda

mailto:[EMAIL PROTECTED]
Phone : (441) 294-4640
Primary Fax : (441) 295-6855 
Secondary Fax : (441) 295-6708

http://www.firstatlanticcommerce.com

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[EMAIL PROTECTED] 
Sent by: [EMAIL PROTECTED] 

07/05/2007 09:15 AM 

 

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RE: [mapguide-users] ODBC Point features failure


  

 

                






Thanks for the response - there is 4GB of RAM on the mapguide server which is 
running Windows Server 2003.  There are no properties selected and there are 
only two layers.   It is pulling data via ODBC from SQL Server on another 
server which is configured similarly.   

I can use the map for a few minutes, zooming, panning, clicking on points, 
etc., but then the points disappear for no reason and the only way I can get 
them back is to restart the mapguide service.   

Is this a bug I should report somewhere? 

Thanks, 

Ian Elsinga
Senior Client/Server Application Developer
First Atlantic Commerce
Bermuda

mailto:[EMAIL PROTECTED]
Phone : (441) 294-4640
Primary Fax : (441) 295-6855 
Secondary Fax : (441) 295-6708

http://www.firstatlanticcommerce.com

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
The information in this Internet e-mail, including attachments, contains 
information that is confidential and may be protected by attorney client 
privileges. This email, including attachments, constitutes non-public 
information intended only for the use of the designated recipient(s) to which 
it is addressed and may contain legal or financial information which is 
privileged, confidential or subject to copyright. Access by any other person to 
this Internet e-mail is not authorized. If you are not the intended recipient, 
please delete this Internet e-mail, including attachments, immediately and 
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action taken or omitted to be taken in reliance on it is prohibited, and may be 
unlawful.

"Dave Wilson" <[EMAIL PROTECTED]> 
Sent by: [EMAIL PROTECTED] 

07/04/2007 06:47 PM 

 

Please respond to
MapGuide Users Mail List <[email protected]>

 

To

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cc

        
Subject

RE: [mapguide-users] ODBC Point features failure


  

 

                






In house testing with a feature source containing almost 10,000 features 
appears to work fine. 

How much memory on your system? What is the OS? Do you have properties selected 
on your layer? How many other layers are in your map? 

Regards, 
Dave 

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Wednesday, July 04, 2007 10:33 AM
To: [email protected]
Subject: [mapguide-users] ODBC Point features failure 


I am using MGOS 1.2 RC2 and am experiencing a problem with an ODBC connected to 
SQL Server point source.    Points are displayed initially, but then eventually 
they are not displayed any longer.  Opening a new web browser does not help.  
The only way I can get them to come back is to restart the MapGuide windows 
service - then the points will come back - for a few minutes of interaction.   

I am bringing back 1000 points from a SQL Server database.    This behaviour 
was the same in 1.2 RC1. 

This will obviously make mapguide unusable for our purposes - is there a 
problem with the ODBC FDO?   

I will be grateful for any assistance!   


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