Suggestions on Client Server!

[Redsz]

Hi all.

One of our applications in essence is a database replicator. The program runs on the clients machine as a scheduled task. It loops throught all the tables in the database grabbing records that have been modified or added since its last run time. These files are then zipped and sent via ftp to one of our head office servers. These files are unzipped and inserted into the correct table.

Maybe once a moth one of these "packets" of information goes missing. In our situation this is unacceptable!!!

Does anybody have any suggestions or ideas on how to accomplish the same process in a different manner?

We were thinking on using winsock and integrating a true client server approach with two way communication? Good idea? Yes. No.

Thx for your replies.

Jesse

 

[perryf]

Jesse,

At my last gig I was involved in a similar process. Unfortunately, I don't think there is any way to absolutely, 100% ensure that all files are sent/received correctly.

The way they had it setup, which was seemed like a good method of providing an audit trail, was to rename these files and use a sequence number as part of the name, filename.num.

The program that imports can check to make sure that any file imported has the next sequence number from the last import. Any errors can be reported and manually investigated.

PF

 

[terosoft]

The importing program could send back an 'acknowledgment file' to the original sender, and the sender should check for the last packet acknowledgment before sending a new packet. If the acknowledgment doesn´t exists simply send the last packet again and wait for the acknowledgment to send the new packet.

We were thinking on using winsock and integrating a true client server approach with two way communication?

What you say here is to have all the data on the head office server and let the branch office's machines to become clients of head office server? This can be done, but if you do it through internet you must consider speed and security issues.

Gerardo Czajkowski

 

[Mike Lewis]

Jesse,

I can't suggest a solution to your specific problem. However, if you were using a SQL Server back end, you would be able to do the whole thing automatically (more or less) and much more reliably, by using SQL Server's built-in replication features.

Of course, that solution could involve re-engineering the data access of your entire application, so you wouldn't want to do it lightly.

Mike


Mike Lewis
Edinburgh, Scotland

http://www.ml-consult.demon.co.uk