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Full Discussion: Performance issue
Top Forums UNIX for Dummies Questions & Answers Performance issue Post 302499390 by pludi on Thursday 24th of February 2011 09:46:59 AM
Old 02-24-2011
You're probably losing most of the time on the actual output. Each call to printf costs the time of a process spawn. And the file has to be opened, written, and closed on each call.

The below Perl script creates the permutations (same number of records as in your example) in just over 2 minutes on an average sized laptop
Code:
# ./perm.pl
Thu Feb 24 15:28:41 CET 2011
Thu Feb 24 15:30:56 CET 2011
# cat perm.pl
#!/usr/bin/perl

use strict;
use warnings;

my ( $fh1, $fh2, $fh3, $out );
my ( @file1, @file2, @file3 );
system("date");
{
    local $/;
    open $fh1, '<', 'file1';
    my $file1 = <$fh1>;
    @file1 = split /\n/, $file1;
    close $fh1;
}
{
    local $/;
    open $fh2, '<', 'file2';
    my $file2 = <$fh2>;
    @file2 = split /\n/, $file2;
    close $fh2;
}
{
    local $/;
    open $fh3, '<', 'file3';
    my $file3 = <$fh3>;
    @file3 = split /\n/, $file3;
    close $fh3;
}

chomp @file1;
chomp @file2;
chomp @file3;

open $out, '>', 'file2.txt';
foreach my $first (@file1) {
    foreach my $second (@file2) {
        foreach my $third (@file3) {
            printf $out "%-9s %-9s %-9s %-9s %-9s %-9s %-9s %-9s %-9s %-9s\n",
              $first, $second, $third, 4, 5, 1, 2, 1, 5, 2;
        }
    }
}
close $out;
system("date");

---------- Post updated at 15:46 ---------- Previous update was at 15:38 ----------

Addendum: on the very same setup, the script as you have given it managed to produce ~50% of all combinations in about 17 minutes. There has to be something entirely different wrong with your setup for it to take 70 hours.
 

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LEARN ABOUT HPUX

diff3

diff3(1)						      General Commands Manual							  diff3(1)

NAME

       diff3 - 3-way differential file comparison

SYNOPSIS

       file1 file2 file3

DESCRIPTION

       compares three versions of a file, and prints disagreeing ranges of text flagged with these codes:

	      all three files differ
	      file1	is different
	      file2	is different
	      file3	is different

       The type of change required to convert a given range of a given file to some other is indicated in one of these ways:

	      Text is to be appended after line number
			     n1 in file f, where f = or

	      Text is to be changed in the range line
			     n1 through line n2.  If n1 = n2, the range can be abbreviated to n1.

       The  original  contents of the range follows immediately after a indication.  When the contents of two files are identical, the contents of
       the lower-numbered file is suppressed.

	      Produces a script for the
			editor that can be used to incorporate into file1 all changes between file2 and file3 (see ed(1)); i.e., the changes  that
			normally would be flagged and

	      Produces a script to incorporate only changes flagged

	      Produces a script to incorporate only changes flagged

	      Produces a script that will incorporate all
			changes  between  file2  and  file3,  but treat overlapping changes (that is, changes that would be flagged with in normal
			listing) differently. The overlapping lines in both files will be inserted by the edit script bracketed by and lines.

	      Produces a script that will incorporate only changes flagged
			, but treat these changes in the manner of option.

       The following command applies the resulting script to file1.

EXTERNAL INFLUENCES

   International Code Set Support
       Single- and multi-byte character code sets are supported.

WARNINGS

       Text lines that consist of a single period defeat

       Files longer than 64K bytes do not work.

FILES

SEE ALSO

       diff(1).

																	  diff3(1)
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