Re^5: Thread Design help

[Corion]

The following code works for me.

use strict;
use threads;
use Data::Dumper;
use Thread::Queue;

warn "Using threads $threads::VERSION";
warn "Using Thread::Queue $Thread::Queue::VERSION";

my $THREADS = 2;

my %dataEntity;

while(<>){
    chomp;
    next if !length($_);
    my ($dsName,$passwd) = split /\|/, $_;
    $dataEntity{$dsName} = $passwd;
}

my $request  = Thread::Queue->new;
my $response = Thread::Queue->new;

# Submit all requests
for my $dbname (keys %dataEntity) {
    $request->enqueue([$dbname,$dataEntity{$dbname}]);
};

sub getConn {};

# Tell each thread that we're done
for (1..$THREADS) {
    $request->enqueue(undef);
};

# Launch our threads
for (1..$THREADS) {
    async(\&getData);
};
sub getData {
    my $idx = 1;
    while (my $job = $request->dequeue()) {
        my ($dbname, $credentials) = @$job;
        #connect to DB, retrieve information
        my $dbh = getConn($dbname,$credentials);
        my %results;
        #my $resArrRef = $dbh->selectall_arrayref("select srvname,dbna
+me from syslogins",{ Slice => {} });
        # package some dummy results
        my $resArrRef = [
            { srvname => "server:$dbname:".$idx++, dbname => $dbname, 
+},
            { srvname => "server:$dbname:".$idx++, dbname => $dbname, 
+},
            { srvname => "server:$dbname:".$idx++, dbname => $dbname, 
+},
            { srvname => "server:$dbname:".$idx++, dbname => $dbname, 
+},
        ];
        foreach my $row ( @$resArrRef ) {
            $results{$row->{srvname}} = $row->{dbname};
        }
        $response->enqueue(\%results);
    };
    # tell our main thread we're done
    $response->enqueue( undef );
};

while ($THREADS) {
    while (my $payload = $response->dequeue()) {
        print Dumper $payload;
    };
    $THREADS--
};

Output

Using threads 1.73 at tmp.pl line 6.
Using Thread::Queue 2.11 at tmp.pl line 7.
qwe
asd
yxc
zui
jjj
^Z
$VAR1 = {
          'server:asd:4' => 'asd',
          'server:asd:2' => 'asd',
          'server:asd:1' => 'asd',
          'server:asd:3' => 'asd'
        };
$VAR1 = {
          'server:zui:5' => 'zui',
          'server:zui:7' => 'zui',
          'server:zui:8' => 'zui',
          'server:zui:6' => 'zui'
        };
$VAR1 = {
          'server:jjj:9' => 'jjj',
          'server:jjj:11' => 'jjj',
          'server:jjj:10' => 'jjj',
          'server:jjj:12' => 'jjj'
        };
$VAR1 = {
          'server:yxc:14' => 'yxc',
          'server:yxc:15' => 'yxc',
          'server:yxc:13' => 'yxc',
          'server:yxc:16' => 'yxc'
        };
$VAR1 = {
          'server:qwe:18' => 'qwe',
          'server:qwe:19' => 'qwe',
          'server:qwe:20' => 'qwe',
          'server:qwe:17' => 'qwe'
        };
Perl exited with active threads:
        0 running and unjoined
        2 finished and unjoined
        0 running and detached

[perlCrazy]

do you think, this is causing problem ?
do i need to get latest version of modules:
Using threads 1.05 at ./thread2.pl line 9. Using Thread::Queue 2.00 at ./thread2.pl line 10. Invalid value for shared scalar at /opt/perl-5.8.6_1/lib/5.8.6/Thread/Queue.pm line 90, <> line 10.
which is the most stable version of perl for thread purpose ?

[BrowserUk]

The combination of this line:

    $request->enqueue( [$dbname,$dataEntity{$dbname}] );

And the very down-level version of threads you are using is almost certainly the source of your problem.

You might be able to fix it without upgrading by changing the code to be:

use threads::shared;
...

for my $dbname (keys %dataEntity) {
    my @args :shared = ( $dbname,$dataEntity{$dbname} );
    $request->enqueue( \@args );
};

But I would still suggest upgrading threads, threads::shared and Thread::Queue ASAP.

[perlCrazy]

Thanks for reply and help Browser UK.
Need you help and opinion for disigning this collector.
Requirement: I will have many dataservers and host that will be divided in multiple groups( wil contain dataservers). We need to connect to each of dataserver/host and execute some commands/utility and process the data, bring back the data and write into a file.
ex: DSA1,DSA2...DSAN
1. conenct to DSA1, process and get the data and write into a file
2. once we get the data back from DSA1, may be after 1/2 hour will need to conenct again and get back data...this will continue depending on interval time.
above step 1 and 2 should run for many servers ( may be 1000s). Do you think thread queue is best way for this requirement ?
is below code is the best way to move forward ? how will I run the job again for particular group or DSA on demand basis?
Thanks a lot for your help in advance. any suggestions/directions will help.

#!/usr/bin/perl

use strict;
use threads;
use Data::Dumper;
use Thread::Queue;

warn "Using threads $threads::VERSION";
warn "Using Thread::Queue $Thread::Queue::VERSION";


my $THREADS = 3;

my %dataEntity;

while(<>){
    chomp;
    next if !length($_);
    my ($dsName,$passwd) = split /\|/, $_;
    $dataEntity{$dsName} = $passwd;
}
my $request  = Thread::Queue->new;
my $response = Thread::Queue->new;

# Submit all requests
for my $dbname (keys %dataEntity) {
    $request->enqueue([$dbname,$dataEntity{$dbname}]);
};

# Tell each thread that we're done
for (1..$THREADS) {
    $request->enqueue(undef);
};

# Launch our threads
for (1..$THREADS) {
    async(\&getData);
};
sub getData {

    ##
    my $idx = 1;
    while (my $job = $request->dequeue()) {
        my ($dbname, $credentials) = @$job;
        #connect to DB, retrieve information
        #my $dbh = getConn($dbname,$credentials);
        my %results;
        #my $resArrRef = $dbh->selectall_arrayref("select srvname,dbna
+me from syslogins",{ Slice => {} });
        # package some dummy results
        my $resArrRef = [
            { srvname => "server:$dbname:".$idx++, dbname => $dbname, 
+},
            { srvname => "server:$dbname:".$idx++, dbname => $dbname, 
+},
            { srvname => "server:$dbname:".$idx++, dbname => $dbname, 
+},
            { srvname => "server:$dbname:".$idx++, dbname => $dbname, 
+},
        ];
        foreach my $row ( @$resArrRef ) {
            $results{$row->{srvname}} = $row->{dbname};
        }
        $response->enqueue(\%results);
    }
    # tell our main thread we're done
    $response->enqueue( undef );
    ##
}

while ($THREADS) {
    while (my $payload = $response->dequeue()) {
        print Dumper $payload;
    };
    $THREADS--
}
sub getConn {
  my ($DB,$pwd) = @_;
  return $dbh;
}

[Corion]

Well, I use the following versions:

Using threads 1.73 at tmp.pl line 6.
Using Thread::Queue 2.11 at tmp.pl line 7.

So maybe just upgrading Thread::Queue or upgrading threads, or upgrading both might help. The posted code works for me, that's all I can say.