in reply to Application Not Responding

Ok, I obviously should have said more. My app is compiled using PerlApp. It is a very simple Perl/Tk widget which has three buttons: backup, restore, and exit; each calls a subroutine to handle the action.

Backup subroutine shutsdown an Oracle 8i database, creates a .zip archive, and puts the contents of two arrays (filenames) into the archive and writes the .zip file. The first array is a list of the database files (these range from 50 MB to 400 MB in size), the second array are user files such as output reports and queries which are almost all less than 50 KB. It does not show a progressbar because it takes less than a second to add all the files to the zip archive (the loop) but it takes over ten minutes to complete the command $zip->writeToFileNamed($new_zip_file). While this one command is running, NT shows my app as "Not responding".

Restore opens a top-level widget with a listbox allowing the user to choose which backup to restore. When they select one and press the "OK" button, it shuts down the database unless it's already shutdown, builds an array with the name of every file in the archive and then extracts each one displaying a progress bar based on the number of files extracted '$percent_done = int(($file_num / $total_files) * 100)'. Even with the progressbar up, the application shows as "Not responding".

Exit restarts the database if it was shutdown and then destroys the widget.

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Re: Re: Application Not Responding
by Thelonius (Priest) on Feb 28, 2003 at 01:47 UTC
    What you need to do is create a subprocess. If this were C/C++, you would create a thread, but I don't think you can do that with Perl/TK on Windows.

    Anyway, the subprocess does all the time-consuming stuff and sends back progress/error/completion reports via an IPC mechanism (e.g. a socket). You can use Tk::Event->fileevent for the parent process to get these notifications. Meanwhile the parent process is responding to normal window messages.

    Update: Well, I spoke too soon. fork() blows chunks with Perk/Tk under Win32 and fileevent doesn't work either (althought it may "soon"). You can create a subprocess using Win32::Process. For one approach to IPC, see this.

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Re: Re: Application Not Responding
by BrowserUk (Patriarch) on Feb 28, 2003 at 02:11 UTC

    As all you need is an indication of when the task is finished, you can fork a subprocess and write the file from there leaving the parent process to maintain the gui and report when the background process has completed.

    This works fine under AS 5.6.1 and 5.8, whether PerlApp can handle it I have no experience.

    ..and remember there are a lot of things monks are supposed to be but lazy is not one of them

    Examine what is said, not who speaks.
    1) When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
    2) The only way of discovering the limits of the possible is to venture a little way past them into the impossible
    3) Any sufficiently advanced technology is indistinguishable from magic.
    Arthur C. Clarke.
[reply]
      Thanks all for your help. I've gotten around my problem for this particular case by delving deep into other people's modules. Basically, I re-wrote the Archive::Zip module so that I could pass it two new variables ($window_handle & $percent_done_reference). Then, after every chunk of data is written out to file, I redo the math for percentage done $$percent_done_reference = 100*($total_size - $self->_readDataRemaining)/$total_size; and then update the window $window_handle->update();. The update happens often enough that my program very rarely falls into "Not Responding" status. I happen to also be using the $percent_done variable in a progress bar. :)

      Again, thanks for the help!
      Arden

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        Have you contacted the author to offer your patch? I'm sure you're not the only one to run into this (or a similar) problem.

        ------
        We are the carpenters and bricklayers of the Information Age.

        Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

        Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.

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