in reply to Threaded script eating memory

I am using Perl 5.8.5,

Try upgrading your perl.

I see no memory leaks at all on my system under both:

Update: Probably irrelevant as this is only demo code, but you are doing some mighty peculiar things.

  1. There is no need to share my $q : shared       = Thread::Queue->new();

    They are created shared.

  2. Why are you creating your big strings inside 1-element anonymous arrays: 
    while ( my $v = ["this is a test" x 250] ) {

    [download]
    to then pluck it out and push it onto your shared array: 
    push @$ary, $v->[0];

    [download]

There is weirdness with your whole architecture, but it's pointless debugging a demo app. If you can post the real code, or a sanitised but still representative example, then I would take a look at that.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
RIP PCW

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Re^2: Threaded script eating memory
by suaveant (Parson) on Jun 22, 2009 at 21:00 UTC
    Not the simplest of options... I'm on a shared system managed by other people... I can try on another system of mine.. maybe I can convince people to upgrade... or maybe I'll just have to re-write it in a less clever fashion.

                    - Ant
                    - Some of my best work - (1 2 3)

[reply]

      There really is no better way to work around fixed core bugs than upgrade.

      However, if memory serves, the main problems with threads in 5.8.5 was leaking closures. It is possible that my rearranging your code (physically within the source file) to avoid unnecessary closures you might be able to avoid the leaks you are seeing.

      The first step is to move all your subroutines to the top of the source file after the use lines, but before you declare any package level variables. Eg: for your demo code, you might do something like this: 

      use threads;
use threads::shared qw(share);
use Thread::Queue;
use Thread::Semaphore;

sub load_queue {
    my $q       = shift;
    my $loading = shift;

    my $i = 1;
    my $ary = &share( [] );
    while ( my $v = ["this is a test" x 250] ) {

        #        print "$v->[0]\n";
        push @$ary, $v->[0];
        unless ( $i++ % 10000 ) {
            print "$i\n";
            $q->enqueue($ary);
            $ary = &share( [] );
            while ( $q->pending() > 20 ) {    # try not to eat tooo mu
+ch memory
                 select(undef,undef,undef,.1);
            }
        }
    }
    $q->enqueue($ary) if @$ary;
    $$loading = 0;
}

sub type_issues {
    my ( $q, $loading ) = @_;
    #my $DB = IDC::Data->new( bes => 'webdev' );
    print "Type issues\n";
    my $issues;
    while ( ( $issues = $q->dequeue() ) ) {
        print "Got ".@$issues." - ".$q->pending()."\n";
        select(undef,undef,undef,.1);
    }
}


my $q = Thread::Queue->new();
my $loading : shared = 1;
my $threads : shared = 0;

my $thr = threads->create( \&load_queue, $q, \$loading );
$thr->detach();
$|++;

my @threads;
for ( 1 .. 6 ) {
    my $thr = threads->create( \&{type_issues}, $q, \$loading, $thread
+s );
    push @threads, $thr;
}

$_->join() for @threads;

      [download]

      Note:That makes no attempt to address any of the other issues I mention in my update to my first reply above.

      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
        It didn't help, but that's probably just as well... hocus-pokery like that is a maintenance accident waiting to happen. Thanks for the help, though.

                        - Ant
                        - Some of my best work - (1 2 3)

[reply]
      Different versions of Perl can happily co-habit one machine.
[reply]
        True, though I don't know if the Admins would be big fans of maintaining two... I have often considered maintaining my own Perl in our product releases though... I already handle my own Perl modules this way.

                        - Ant
                        - Some of my best work - (1 2 3)

[reply]
Re^2: Threaded script eating memory
by suaveant (Parson) on Jun 23, 2009 at 14:12 UTC
    The anonymous array and the $v->[0] are just remnants of the real code which did a fetchrow_arrayref.

    I didn't realize the Queues were shared though it makes sense.

                    - Ant
                    - Some of my best work - (1 2 3)

[reply]
[d/l]

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