[rrd-users] Fetching from the beginning of an RRD file

[Alex van den Bogaerdt]

On Sat, Mar 03, 2007 at 10:18:30AM -0800, Travis Spencer wrote:
> On 3/2/07, Alex van den Bogaerdt <alex at ergens.op.het.net> wrote:
> > If you're interested in as much data as possible, without paying too
> > much attention to resolution, go for the RRA with the largest amount
> > of time in it.
> 
> I'm only interested in knowing the oldest time stamp for the AVERAGE
> CF.  The least expensive, quickest way to get this is what I would
> like.

Define "the" average cf.

> What do others think of a patch to allow a start time of `beginning'
> which would go through the steps Alex has outlined in previous posts
> to include data from the "beginning" of an RRD file?  Thus,
> 
>     rrdtool fetch foo.rrd AVERAGE -s beginning
> 
> would return the all averages in foo.rrd.


Questions you need to answer:
Which RRA should be selected, in different cases?  Example: what
if no resolution is mentioned, what if an existing resolution is
mentioned, what if a resolution is mentioned which is not available?

You also say: "I'm only interested in knowing the oldest time stamp"...
So, similar to "rrdtool last", you are proposing "rrdtool first".
That's different from getting data out of RRAs.

quote:
$ rrdtool first
RRDtool 1.2.12  Copyright 1997-2005 by Tobias Oetiker <tobi at oetiker.ch>
               Compiled Apr 27 2006 13:22:35

Usage: rrdtool [options] command command_options

* first - show first update time for RRA within an RRD

        rrdtool first filename.rrd [--rraindex number]

RRDtool is distributed under the Terms of the GNU General
Public License Version 2. (www.gnu.org/copyleft/gpl.html)

For more information read the RRD manpages
$
endquote

No, I have not tried this myself.

HTH
-- 
Alex van den Bogaerdt
http://www.vandenbogaerdt.nl/rrdtool/