Beefy Boxes and Bandwidth Generously Provided by pair Networks
Problems? Is your data what you think it is?

scripts die when calling other program, but only certian circumstances

by xxqtony (Initiate)
on Oct 18, 2008 at 05:15 UTC ( #717906=perlquestion: print w/ replies, xml ) Need Help??
xxqtony has asked for the wisdom of the Perl Monks concerning the following question:

Hi, hopefully someone can help me out.

Short version: my scripts is a GUI wrapper which directly/indirectly calls other applications, it runs ok with small datasets, but dies when I test it with large datasets.

Long form: I'm using Perl/Tk to design a GUI, in the scripts a subroutine A calls another Perl scripts, which in turn calls a third party application C. I have lines like this:

my $call = system(" -a option1 -b option2 -c option3");

my $res = $path . "$result_file_generated_by_application_C";

The lines work no problem when my datasets are small (1 Gigs), and with small datasets, it takes about 2 or 3 minutes for C to complete; however the line of 'my $res' complains uninitilized $result_file_generated_by_application_C when my testing datasets are big (10 Gigs); with big datasets, it usually takes 10-30 minutes for C to complete. In the failing case, I found no result_file_generated_by_application_C file generated. In another word, it looks like my scripts keeps going forward even the calling of (and then calling application C) does not finish.

I wonder if the problem is because my scripts calls B, which is submitted and returned, even C is still running. However, if my guess is right, then it should have problem too even when my datasets are small. Since no code available for application C, I think maybe I should try to incorporate codes into my scripts, which I hate to do because of legal issue.

Anyone knows what might cause the problem when my datasets are big? I don't think it's memory issue, because it can run in non-GUI version no problem.

Comment on scripts die when calling other program, but only certian circumstances
Replies are listed 'Best First'.
Re: scripts die when calling other program, but only certian circumstances
by Perlbotics (Canon) on Oct 18, 2008 at 09:10 UTC

    Can you elaborate on die? Do you mean, your GUI window disappears, or does the GUI freeze ... ?

    You could check:

    • the return value $call: was a signal caught?
    • the string given to system(): does it contain characters which are interpreted by the shell - maybe in the 'C'-case only? Alternatively, try system with a list argument.
    • for any output your chain of calls send to STDOUT and STDERR
    • experimentally, if the problem is in your GUI by running e.g. system("sleep 2000") instead of
    • memory consumption again

    Because of submitted and returned, even C is still running..., maybe an unescaped & sneaked into the system call? That could also explain the uninitialised $res, because the result is not yet ready for long running tasks when the GUI checks for the result-files existence. For short running tasks, some (maybe not all) results are processed and the result file is already opened/created, giving the impression the GUI work fine for small tasks. Well, just some speculations...

Re: scripts die when calling other program, but only certian circumstances
by zentara (Archbishop) on Oct 18, 2008 at 12:44 UTC
    If I understand your question correctly, you probably need to put your long db stuff into a separate thread. Calling a long system command in a Tk program will interfere with the eventloop, and make it unresponsive while system is running.

    As a quick test, can you fork off the commands(instead of system), and write the results to a file? If forked, does Tk stay alive?

    I'm not really a human, but I play one on earth Remember How Lucky You Are
Re: scripts die when calling other program, but only certian circumstances
by Anonymous Monk on Oct 18, 2008 at 06:21 UTC
    when a program die's, there's an error message

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: perlquestion [id://717906]
Approved by CardinalNumber
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others drinking their drinks and smoking their pipes about the Monastery: (6)
As of 2016-02-13 11:38 GMT
Find Nodes?
    Voting Booth?

    How many photographs, souvenirs, artworks, trophies or other decorative objects are displayed in your home?

    Results (428 votes), past polls