[rrd-users] Strange fetch behaviour (even stranger in the python bindings)

[Alex van den Bogaerdt]

On Mon, Feb 04, 2008 at 08:51:40PM +0200, Dimitris Karteris wrote:
> Hi to all,
> 
> I'm having some problems with fetch. It just doesn't seem to get things 
> right as far as "start" and "end" arguments are concerned. I'm kinda 
> newbie in rrdtool so I hope I'm not missing something here. Anyway, here 
> goes: I'm trying to fetch some values from an rrd file with step set to 
> 1. Here's what I get for the 1201849690 to 1201849693 time series:

I can explain half of it.  The other half is for somebody else.

>   $ rrdtool fetch lights_corridor.rrd LAST \
>                   -s 1201849690 -e 1201849693

You ask here for an interval starting at 1201849690, ...

>                             main
> 
>   1201849691: 0.0000000000e+00
>   1201849692: 0.0000000000e+00
>   1201849693: 0.0000000000e+00
>   1201849694: 0.0000000000e+00

... and aparently you are using step size 1 in your database.  Each
interval in your database is one second large, the entry marked
1201849691 is actually starting at 1201849690 !

That does not explain why you got to see 1201849693..1201849694, and
I cannot explain either.

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