Help me in chat application !

I used indy TCP to make chat application both in client and server.

after a time (about 3 hours upper), CPU of server.exe near 100%, make my system LAG

I know function sleep() can solve this problem but I dont know where to put function sleep in.
in client code or in server code,

or is there a better way for server.exe than use sleep ?

please help me in detail.

thank all experts.

Who is Participating?
Wim ten BrinkSelf-employed developerCommented:
I don't think Sleep() will solve this problem. All sleep does is halt the current thread and give another thread some CPU time. In general you would use Sleep(0) and not Sleep(1) if you just want another thread to start processing a bit more. (A Sleep(1) would add a delay of one millisecond, which might slow down your app considerably if you execute it often enough.)

The question is of course why your system needs so much CPU time. Maybe you're running out of memory because of a memory leak. Then it would be swapping to the swapfile. Or maybe something else is going wrong. Are you testing on multiple computers, where one is running the server and the other the client(s)? If so, which computer gets the 100% CPU?

It could also be that your application is calling Application.ProcessMessages or Sleep() too often. But I don't think Sleep() will solve it.

you will put a sleep(1) tipically or other small value in  loopes that take "forever" without doing anything. like

while not terminated do

it is also advisable that you put application.processmessages; calls in such repetitive structures.
also, when doing client-server applications, you must use threads at least on teh server side to habdle client connections.
there are also other general issues that can cause a cpu eating up 100%.

so better post the code here so we can see exactly where those issues are. (maybe sleep is not the answer ;) )
TheRealLokiSenior DeveloperCommented:
the server runs its' clent connections inside a thread, so you do not need sleep
I would look for the problem elsewhere
can you post some of your code, and we might be able to spot the real problem
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Have to agree here with TheRealLoki, we do not have enough information to help you. Also as Loki said its not a thread problem more likely a source twitch...
So paste you code where you think it use the most CPU time...

Peace Scay7
lhquangAuthor Commented:
the source code I developed from the chat demo in INDY 9. thank experts
TheRealLokiSenior DeveloperCommented:
The Indy 9 chat demo is very buggy
firstly, the client can lock up on the
Msg := IdTCPClient1.ReadLn('', 5);
line in the Timer1Timer() event

This can be resolved by putting a TIdAntiFreeze on the form, but you still get a memory leak
(just watch the task maanger while your client is connected)
To resolve this you need to disable the TTimer while doing the ReadLn, so your Timer1Timer routine ends up looking something like this :-

procedure TForm1.Timer1Timer(Sender: TObject);
  Msg : String;
  if not IdTcpClient1.Connected then
  Timer1.Enabled := False;
    Msg := IdTCPClient1.ReadLn('', 5);

    if Msg <> '' then
      if Msg[1] <> '@' then
        { Not a system command }
        { System command }
          Com := UpperCase(Trim(Copy(Msg, 2, Pos(':', Msg) -2)));
          Msg := UpperCase(Trim(Copy(Msg, Pos(':', Msg) +1, Length(Msg))));
          if Com = 'CLIENTS' then
            lbClients.Items.CommaText := Msg;
      Timer1.Enabled := True;

anyway, this may be the cause of your problems...
lhquangAuthor Commented:
anyone can give me the better demo than INDY DEMO ?
lhquangAuthor Commented:
oh, now I found out the my problem and fixed it.

thank everybody
Wim ten BrinkSelf-employed developerCommented:
Am just curious... What was the error exactly? :-)
Which reminds me... memlines.lines.add just keeps adding strings to a memo field. Does it also clean up this memo a bit? If not, lots of memory usage there...
lhquangAuthor Commented:
Workshop_Alex , u r right, memlines.lines.add just keeps adding strings to a memo field and I solved it
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