Shared variable engine memory problem

Question

Hello,
I have a lot of problems with DSC 8. The server that worked very well in DSC 7, in DSC 8 is creating a lot of problems starting with memory leaks in tagsrv process. I have over 5000 shared variables and when I publish them the tagsrv is around 90Mb of memory. After approx. 30 min is around 130Mb and so on until the computer becomes useless. If I restart the computer the process is the same, even if I don't start the VI that updates the shared variables. I tried to uncheck different things in the variables definition like: no alarming, no buffering, no scaling, with no improvement.
Is there a way to undeploy the shared variables or processes manually, not from the labview project, or Variable Manager. To undeploy the mentioned library with the Variable Manager takes more that an hour (just to enumerate all the shared variables).
Any suggestion is welcomed,
cosmin

Answer 1

cosmin,
  I have several thoughts for you.  First, I recommend
splitting up
your 5000 variable library into a set of smaller libraries.  In
contrast
with the LabVIEW DSC 7 engine, the LabVIEW 8 Shared Variable Engine is
optimized for multiple smaller libraries.  I would recommend
having at
most about 1000 variables per library.  You'll see some different
recommendations from different people at NI, but in my personal
experience I
think 1000 is about as many Shared Variables that can be easily managed
at
once.  For your case this would mean having 1000 variables in 5
different
libraries.   --Splitting up your library gives you the added
benefit of being able to
undeploy/disable individual libraries without affecting the other
libraries.  Unfortunately, the SCF migration tool will not do this
for you manually so it may take a little time to get everything
organized.
  Your comment about ever-increasing memory usage is
concerning.  Do
you see this while deploying your library, or while writing
values?  If
you write to values very fast (like in an untimed loop) for an extended
period
of time memory usage will increase as the variable buffers
increase. 
Please elaborate more on this topic and let me know what happens if you
separate your variables into multiple libraries.  I was not able
to reproduce this on a similarly spec'd computer using 10 libraries of
500 variables each.
  You can programmatically undeploy libraries using the delete process VI
on the DSC Engine Control palette in LabVIEW.  Use this VI in combination
with the get process list VI to quickly remove all currently deployed
libraries.
  Also, regarding your question about why variables sometimes show up the
Published Variable Monitor window; the different utilities you described may
use different methods to get that variable list.  These methods behave
differently depending on how stressed the Shared Variable Engine is.  If
you're in the middle of loading a library with 5000 variables I'm not surprised
that the list won't get populated immediately in the Published Variable Monitor
window.  After the library successfully loads though, you should be able
to refresh the view and see all the variables. 
Regards,
Nick F
LabVIEW R&D
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