Solved

Memory

Posted on 2003-11-26
8
323 Views
Last Modified: 2010-04-05
Hi,

Can anyone tell me how to create a program as memory efficient as possible.
Do you need to create all objects in code to do this?
Are there any more ways than, Free, FreeAndNil etc to release memory once
my program has finished with it.

I have a program that has a timer and every 10 seconds it runs code to process instructions on a database. I use query's to access the data and also to update my data. But as my program runs, which is 24/7, I can see the Mem Usage in Task Manager slowly accumulating over time. I create all my query's in code and free them up once im finished so I am struggling to think why this memory is accumulating over time.

I am using Delphi 5 Pro and my app is a standard windows exe.

Any help would be greatly appreciated
Thanks
0
Comment
Question by:HotRod40
8 Comments
 

Expert Comment

by:lamtl354
ID: 9829397
hi,

you could:
use less Database object as posssibly
create object dynacmic instead of placing on form
free up (obh.free) after use.

hope helps
0
 
LVL 2

Expert Comment

by:Robn
ID: 9831885
Is it possible for this routine to take longer than 10 seconds to complete? If so, depending on how your code was written, you may be creating objects that are already created and then loosing the reference to them.

Just a thought.

You may also have a memory leak somewhere in your code that you may not see right now.
0
 
LVL 3

Expert Comment

by:gandalf_the_white
ID: 9857251
if you create objects with AOwner set to self you will not have a memory leak if you close
the application but during the runtime of the programm you will
experience incrementing memory usage

0
 

Author Comment

by:HotRod40
ID: 9873408
Gandalf,

Is there any other options to set AOwner to other than Self ?

Thanks
0
Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

 
LVL 2

Expert Comment

by:Robn
ID: 9874235
I've seen code where a form is created with Application as the owner. I personally do not like this coding style. I also don't like to code objects that stick around for longer than they need to be.

However, I have seen some recent posts on EE where they talk about memory leaks in the Query objects (I'm not a DB guy so I'm not really sure if this applies to you). Your code may be correct and the problem may lie elsewhere.

Here are some links
http://www.experts-exchange.com/Programming/Programming_Languages/Delphi/Q_20815252.html
http://www.experts-exchange.com/Programming/Programming_Languages/Delphi/Q_20812633.html

Regards,
Rob
0
 
LVL 3

Expert Comment

by:gandalf_the_white
ID: 9880795
you can set the owner to nil

that also means you have to free the objects yourself.

but that also means that you can free the objects at the time you
want and you must not wait until the Owner is freed.

for instance:


procedure formcreate()
begin
  myPanel := TPanel.create(nil)
  mypanel.parent := Mainform;  { to show it somewhere }
...
end;

procedure Formdestroy();
begin
  myPanel.free;
 
...
end;


you can call the mypanel.free anywhere you like
but it also means if you forget it you have a memory leak after the programm is closed


0
 
LVL 2

Expert Comment

by:Robn
ID: 9882034
gandalf_the_white is correct, however to avoid any confusion, you can still create the panel with an owner and free it anytime you like before the owner is freed. When this happens, the owner will Remove that component from its internal list so that it knows not to free it when it is destroyed.

However, I still bet the leak isn't in your code but in the components you are using (then again, I haven't seen your code).

Regards,
Rob
0
 
LVL 3

Accepted Solution

by:
gandalf_the_white earned 150 total points
ID: 9903532
my point was that if you create components with Owner set to the form during runtime
they are not freed until the program is closed.

that means your memory usage will raise during the execution if you create ANY Components during runtime.
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
Hello everybody This Article will show you how to validate number with TEdit control, What's the TEdit control? TEdit is a standard Windows edit control on a form, it allows to user to write, read and copy/paste single line of text. Usua…
Migrating to Microsoft Office 365 is becoming increasingly popular for organizations both large and small. If you have made the leap to Microsoft’s cloud platform, you know that you will need to create a corporate email signature for your Office 365…
Sending a Secure fax is easy with eFax Corporate (http://www.enterprise.efax.com). First, just open a new email message. In the To field, type your recipient's fax number @efaxsend.com. You can even send a secure international fax — just include t…

912 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

18 Experts available now in Live!

Get 1:1 Help Now