[rrd-users] Re: Inconsistencies between graph and fetch

[Philip Molter]

: Today Philip Molter wrote:
:
:  |
:  | I'm using 1.0.28 on a Solaris 8 x86 box with the Perl hooks.
:
: make sure you are using 1.0.33 ... (hint hint)

Ugh, I upgraded everything to 1.0.33 and now graphing is one off
in the other direction.

For example, with the same setup, I get these results from RRD fetch:

  Time      test1      test2
  ---------------------------
  $time + 5   5         NaN
  $time + 10  3         2
  $time + 15  4         4

But when I do averages using graph for the exact same start and
end times ($time + 5 through $time + 15), I get averages of test1:3.5
and test2:3.  If I increase the period by doing (-s $time + 5 -
1), then I get the correct values back using rrdgraph.

Again, that seems like a pretty big inconsistency.  I would expect
my 'graphed' values to be using the same data that my fetch query
returns.  Apparently, now, graphing is inclusive of the ending
time, but exclusive of the start time, while fetching is still
inclusive of both.

I've included my previous message below for refernece
Philip

----- Previous Message -----

: I've setup a very basic file for testing.  Two fields, 5 second
: intervals, starting at time $time ($time is adjusted to be on a 5
: second boundary).
: 
:   Field test1 is a GAUGE
:   Field test2 is a COUNTER
: 
: At these times, I put in these values:
: 
:   Time       test1      test2
:   ----------------------------
:   $time + 5    5          8
:   $time + 10   3          18
:   $time + 15   4          38
: 
: When I do a fetch for the time period starting at $time + 5 and
: ending at $time + 15, I get these three rows:
: 
:   Time       test1      test2
:   ----------------------------
:   $time + 5    5         NaN
:   $time + 10   3         2
:   $time + 15   4         4
: 
: Thus, using that data, between the times of $time + 5 and $time +
: 15, I get an average value of 4 for test1 and 3 for test2.
: 
: However, if I do a graph using the following values:
: 
:   -
:   -s $time + 5
:   -e $time + 15
:   DEF:test1=file.rrd:test1:AVERAGE
:   DEF:test2=file.rrd:test2:AVERAGE
:   PRINT:test1:AVERAGE:%lf
:   PRINT:test2:AVERAGE:%lf
: 
: I get back averages of 4 for test1 and 2 for test2.  It's like it's
: ignoring the $time + 15 entry for calculating the average value.
: If I increase the period by using (-e $time + 16), then I get the
: correct values.

* Philip Molter
* DataFoundry.net
* http://www.datafoundry.net/
* philip at datafoundry.net

--
Unsubscribe mailto:rrd-users-request at list.ee.ethz.ch?subject=unsubscribe
Help        mailto:rrd-users-request at list.ee.ethz.ch?subject=help
Archive     http://www.ee.ethz.ch/~slist/rrd-users
WebAdmin    http://www.ee.ethz.ch/~slist/lsg2.cgi