Windows memory management?

Hi all.

I've been told by my client that the server application I'm working on has inacceptable memory requirements, since after five days of nonstop running it gets 70 MB of memory (as shown in Task Manager). So I immediately checked the program in debug and gave it a stress to at least approximately simulate the utilization it has in real usage by the client.

I found just some small leaks, which occur just once while starting the program, anyway. So nothing useful.

Few hours later he mailed me again that after changing some settings in the program and clicking OK in that settings dialog, the memory usage fell to 16 MB.

How is it possible? I checked the handler for OK button in that dialog, nothing special there.

Do you have some explanation?

I now something must go wrong because of those 70MB, but I don't understand the sudden fall after confirmating the dialog..

Thank you for all suggestions.

I don't mean to be disrespectful - but if you don't understand what's happening, what chance have we got?? You don't give us any code to look at. You don't tell us what the program does. You don't say what the Settings dialog was for or what settings were changed to produce the improvement. What have we got to go on? We don't even know what version of Windows your client uses (some have better memory managaement than others). Also, did any errors occur during the 5 days? All this could be relevant information.

My car broke down last week. Can you tell me what's wrong with it? :D

On a more constructive note - from the information you've given, I'd recommend that you implement some kind of logging system. Every time you call a function that allocates memory, write that fact into a log file. Then write to the log file again whenever that memory is released. If errors occur during your program's lifecycle, write them to the log file too.

Ask your client to run the program for 5 days with the original settings and then send you the log file. Then ask him to run for 5 days with the changed settings and send you that log file too. At the very least, you might be able to tell what the differences are when your client changes from the old settings to the new settings.