It's hard to tell you anything without seeing your code, or even knowing what kind synchronization you use (semaphores? queues?).

If you let the thread sleep for as long as the 13MB download lasts, does the same error occur? Do you actually load the file to memory?

I am not using any synchronzation( no queues, no semaphores). And the second thread is spawned after the file is downloaded completely to the web server.

In the main while loop, i do the following

      foreach (@connections_pending) {
            my $fh;
            my $remote = accept( $fh, $_ );
            my ( $port, $iaddr ) = sockaddr_in($remote);
            my $peeraddress = inet_ntoa($iaddr);
            my $t = threads->create( \&connection, $fh );
      }
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So when the request for file upload comes from front0end, i spawn the thread.

Now, in the connection subroutine, i check if its a POST method and if so, i call a subroutine to handle that

sub upload_file {    
        my ( $fh, $req_ ) = @_;
    my %req     = %$req_;
    my $header_ = $req{HEADER};
    my %header  = %$header_;

        my ($file, $desc, $dirpath ) = (undef, undef, undef);
    my $boundary = trim (form_data_boundary( $header{'content-type'} )
+);
    my $user_agent = $header{'user-agent'};

 # Now i will process the post buffer and copy the file #to local mach
+ine into a temp directory. I shall also #receive the filename, destin
+ation directory and some #other metadata information.

($file, $desc, $dirpath) = process_POST_buffer($fh, $req_, $boundary);

# Then i spawn another thread to do the pre-processing on this file
my $t = threads->create( \&pre_process, $file, $desc, $dirpath );

}
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The pre-process thread does this

sub pre_process {
    threads->detach();
    my ( $file_name, $desc,  $dirpath ) = @_;
    my ( $file1,  $file2, $file3 )   = ( getTempFile(), getTempFile(),
+ getTempFile() );
    my $metadata = i_PreProcessor->new(
        FILENAME      => $file_name,
        SEARCHXMLFILE => $file1,
        DESCRIPTION   => $desc,
        MAPXMLFILE    => $file2,
        TAGXMLFILE    => $file3,
        DIRNAME       => $dirpath
    );
    $metadata->build2();

    #delete temp files.
    my @files = ( $file1, $file2, $file3 );
    unlink(@files);
    threads->exit();
}
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~Arun

I dont think so. The file is completely uploaded. the only problem is the thread does not get spawned.

~Arun