[rrd-developers] Re: RRDs::fetch zero values returns NaN

[Mark Mills]

No, you have Borked your perl code...  You need to test
for "defined"ness rather than truth. 

#!/usr/bin/perl
#

use lib '/usr/local/rrdtool-1.0.33/lib/perl';
use RRDs;
($start,$step,$names,$data) = RRDs::fetch ("$ARGV[0]",'AVERAGE');
if ( $error = RRDs::error ) { 
  print "rrdtool fetch failed: \"$error\"\n";
  exit 1;
}
$d_start = $start;
foreach $line (@$data) {
  print " $d_start: ";
  $d_start += $step;
  foreach $val (@$line) { 
    printf "%1.10e ", $val; 
    if ( !defined $val ) { print " (undef)"; }
  }
  print "\n";
}

-----Original Message-----
From: steve rader [mailto:rader at ginseng.physics.wisc.edu]
Sent: Thursday, March 15, 2001 11:47 AM
To: rrd-developers at list.ee.ethz.ch
Subject: [rrd-developers] RRDs::fetch zero values returns NaN 



 > From: me
 > The problem is that NaN values fetched with RRDs::fetch are now
 > returned as 'undef' instead of the string 'NaN'.  

Now I find that RRDs::fetch is broke with respect to zero values:
with 1.0.33, RRDs::fetch of zero values returns 'undef'.  

I wrote a little script to demonstrate the problem... and here's
the results...

 chive(rader): rrdtool fetch -s -10min -e now \
   /usr/local/nrg/web/apache/Chive/Chive-tp.rrd AVERAGE \
   | tail -4
 984673800: 1.1650888889e+00
 984674100: 0.0000000000e+00
 984674400: 0.0000000000e+00
 984674700:        NaN

 chive(rader): ./rrdfetch.pl \
   /usr/local/nrg/web/apache/Chive/Chive-tp.rrd AVERAGE \
   | tail -4
 984673800: 1.1650888889e+00 
 984674100: 0.0000000000e+00  (undef)
 984674400: 0.0000000000e+00  (undef)
 984674700: 0.0000000000e+00  (undef)

steve 
- - - 
systems & network guy
high energy physics
university of wisconsin
- - - 

#!/usr/bin/perl
#

use lib '/usr/local/rrdtool-1.0.33/lib/perl';
use RRDs;
($start,$step,$names,$data) = RRDs::fetch ("$ARGV[0]",'AVERAGE');
if ( $error = RRDs::error ) { 
  print "rrdtool fetch failed: \"$error\"\n";
  exit 1;
}
$d_start = $start;
foreach $line (@$data) {
  print " $d_start: ";
  $d_start += $step;
  foreach $val (@$line) { 
    printf "%1.10e ", $val; 
    if ( ! $val ) { print " (undef)"; }
  }
  print "\n";
}


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