# [rrd-users] Re: fetch problem?

Alex van den Bogaerdt alex at ergens.op.het.net
Fri Nov 24 20:59:13 MET 2006

```On Fri, Nov 24, 2006 at 12:31:20PM -0500, luc.belleville at connexim.ca wrote:
> May be it has been discus before but I can not find any trace of it.  I
> also check all the release not and I could not find any information on
> it.

It has been discussed here on this list, very recently.

The problem:  1.0.33 returned more than you asked for.

RRDtool round robin archives describe rates during an interval.
Each interval has a start, an end, and a duration.  Two out of
three are necessary to find out which interval you need to look
at.

The duration is "steps times step", in other words the step size
(often 300, 5 minutes) multiplied by the number of these steps
per RRA entry.

Then you need either start or end.  RRDtool was designed to use
the end time.

Assuming 1164214200 is on a boundary, and assuming step==300,
with one step per RRA row (step*steps=300*1=300):

Interval at 1164214200 describes time 1164213900 to 1164214200
Interval at 1164214500 describes time 1164214200 to 1164214500

"--start 1164214199":
the interval describing time 1164213900 to 1164214200 does include
what you ask. This is the interval marked 1164214200.

"--start 1164214200":
the interval describing time 1164214200 to 1164214500 does include
what you ask. This is the interval marked 1164214500.

"--start 1164214201":
the interval describing time 1164214200 to 1164214500 does include
what you ask. This is the interval marked 1164214500.

"--end 1164214199":
the interval describing time 1164213900 to 1164214200 does include
what you ask. This is the interval marked 1164214200.

"--end 1164214200":
the interval describing time 1164213900 to 1164214200 does include
what you ask. This is the interval marked 1164214200.

"--end 1164214201":
the interval describing time 1164214200 to 1164214500 does include
what you ask. This is the interval marked 1164214500.

Notice how "--start 1164214200" and "--end 1164214200" result in
different intervals.

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

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