Memory gradually increasing on running DSCengine.exe

[activeX and labview]

I have updated LabVIEW DSC 6.1 Runtime System Module with the patch "LabVIEW Datalogging and Supervisory Control Module 6.1 fixes, Last update: 2/26/2003" as per the instructions written in the "readme.txt" file along with it.
After that I have created 150 memory tags in the DSC Runtime Module. There is no program to write values to these tags. Only the DSCEngine is run through the run button on the window of the DSC Runtime Module.
I have observed that memory usage of DSCEngine.exe gradually increases over time.
Iam attaching 2 bmps which will clarify the rate of increase of memory which I have observed. Please tell me why is this happening.

[Remzi]

Hi,
Have you had this memory leakage problem before you applied the DSC fixes? Make sure that you are using the latest citadel. You can find the most recent version at
http://digital.ni.com/softlib.nsf/websearch/C1A484551A75614686256AE300734336?opendocument

Regards,
Remzi A.

[activeX and labview]

Hello,

I had this memory problem earlier but then I updated my LOGOS to version 4.5 and applied the fixes. Please clarify what do you mean by 'latest citadel'.

regards,
Ravinder

[Remzi]

Hi,
I meant the latest version of logos, but you said you have already installed it. If you want, I can take a look at the LabVIEW code, please also attach the scf file.
Regards,
Remzi A.

[activeX and labview]

Hello,
I have not written any LabVIEW code for writing values to the 150 tags. Just open the attached scf file in the Tag Configuration Editor, save it and run the DSC engine from the run button on the window of the Tag Configuration Editor. In this condition itself observe the memory usage of DSCRTS.exe/LabVIEW.exe and the DSCEngine.exe for 4 to 5 hours. I have observed slow increase in memory usage of DSCEngine.exe.
My applications run continously (without shutting down for months/years) in the field so this small increase in memory multiplies and finally the PC hangs. I am using a P-IV processor with 256MB RAM and the OS is WinNT 4.0 (S.P. 6.0).
regards,
Ravinder

[Remzi]

Hi Ravinder,
I have observed some changes in memory usage but did not have a chance to run it more then 1 hour. I will test it over the weekend and let you know. On the other hand, I haven't seen the same change in DSC 7.0 version.
Best Regards,
Remzi A.

[Ravinder Jagdev]

Hello,
Please let me know what is your observation ... Iam eagerly waiting for a solution.
regards,
Ravinder

[Remzi]

Hi Ravinder,
Sorry about the delay. What I observed was a very slow increase in the memory usage of DSCEngine.exe but I couldn't determine the rate of increase, because of two reasons, 1) the rate of increase was too slow, it may take a long time to determine it, 2) the rate was different every time I tested it. Although I cannot say for sure that it is a memory leakage problem, I would definitely recommend you to create an e-mail support request at http://www.ni.com/support to let DSC developers know about this issue.

Best Regards,
Remzi A.

[rem]

I have a partial answer for you, and a question.

The partial answer - when logging to Citadel 4 each logging trace has a buffer cache of 4096 byte. It is possible, therefore, that ~600K of this memory increase is related to filling these buffers.

The question - are any alarms associated with these tags? If so there are several possibilities:

1. If any tag is cylcling between two limits (say HI and HIHI), the engine must cache a refnum for each change in the alarm state to be able to acknowledge the alarms in the future.

2. If you have a large number of unacknowledged alarms the engine memory will grow for the reason explained in item #1.

3. There is a small memory leak that exists when auto-acknowledgin alarms. This problem was corrected in 7.0 but
could not be fixed in earlier versions due to architectural limitations.

Hope that helps,
Robert

[Ravinder Jagdev]

Hello Mr. Robert,

I am not using any alarms for the time being, but in future I have to use alarms with the option "User must ack".
Iam sending the test tags which I have used to test the memory leakage problem. Please look into the matter and give me a solution.

Thanks !
regards,
Ravinder