Hi Stacey
We are experiencing the same issues with a similar multi-tiered system using datasnap/midas and were actually just discussing this issue when these postings came through.
Until now we have been using e-mail messages as a means of trying to locate problems, but obviously have to limit the number of messages sent so it is not always catching the issues. We were just kicking around the same basic idea that Dave Jollie replied with and think that this would be the best solution, we curently have the Server app with the ability to run in debug mode "where messages are sent" or standard mode " no messages".
It is now just a matter of finding the actual time to retro fit to existing code..
But will certainly let you know if we find anything obvious...
Cheers
Robert Wilson
| "Stacey Verner" <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED] 02/09/2005 09:48 a.m.
|
To: "NZ Borland Developers Group - Delphi List" <[email protected]> cc: Subject: [DUG] DataSnap/Midas App Server Error |
We have an DataSnap/Midas app server which fails randomly.
We can't make it happen no matter how hard we try, but it happens fairly regularly on our production machine.
A little bit of info on the app and app server:
- The applicaiton is a normal database application.
- The application also needs to get information from a settings (metadata) database such as:
- Which databases they have access to
- What permissions they have on the database etc
- Instead of connecting directly to the settings database we use the app server which shares one database connection between all clients.
- This means that there is one database connection for each application instead of 2 which reduces licencing costs
- We use the borland socket server and a socket connection to connect to the app server.
- When we used a normal DCOM connection each client got its own copy of the app server, so the settings database connection is not shared and in effect each application had two connections to the database.
Sometimes the app server locks up and the clients can't connect.
We have a work around that will try app servers on other machines if this fails which works OK, but if it never gets a connection the all sorts of odd things happen.
Firstly, does anyone have any thoughts on this. Debug ideas etc?
Secondly, when the connection to the app server fails it takes forever (minutes) to return no matter what I set the socket connection timeout to.
Thanks
Stacey
Stacey Verner Ph: +64-9-4154790
Software Developer Fax: +64-9-4154791
DDI: +64-9-4154797
CJN Technologies Ltd. Email: [EMAIL PROTECTED]
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Visit our website at http://www.cjntech.co.nz/
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- When we used a normal DCOM connection each client got its own copy of the app server, so the settings database connection is not shared and in effect each application had two connections to the database.
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