[rrd-developers] Update ex post?

Tobias Oetiker tobi at oetiker.ch
Mon Aug 23 20:30:46 CEST 2010

Hi Till,

Today Till Dörges wrote:

> Hello everyone,
> I know that RRDtool doesn't support updates ex post and that this is by design. I've
> looked around a bit and didn't manage to find a more a detailed reasoning as to why
> this is so. So I'd be very curious about pointers or hints.

the reason is that rrdtool 're-samples' data as you hand it to the
tool and then stores it at the resolution set by --step and the
different RRAs. The whole process is like a conveyor belt ... if
you do not enter at the beginning things get complex ...

> Along the same lines, RRDtool is in deed the best OSS tool I'm aware of for recording
> and visualization of time series :-) - sometimes except for the missing ability to
> provide updates for time slots in the past. I'm wondering how much effort would it
> take to extend RRDtool to provide such a feature? (I've seen rrdgraph_libdbi which is
> already kind of close if you don't worry about aggregation/consolidation.)

have a look at:

this might be an interesting basis for such a feature ...


> TIA -- Till

Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
http://it.oetiker.ch tobi at oetiker.ch ++41 62 775 9902 / sb: -9900

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