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[Nicholas Leskiw <question148743@xxxxxxxxxxxxxxxxxxxxx>]

Question #148743 on Graphite changed:
https://answers.launchpad.net/graphite/+question/148743

Nicholas Leskiw proposed the following answer:
All facets of Graphite, Carbon and Whisper assume that you're using data in
buckets, not time,value pairs. There's lots of good reasons for this as
well. It's one of those things that looks simple at first, (oh, sure, just
make 'em time value pairs.) but becomes deviously complicated in the
implementation. Changing this would practically be a complete re-write of
the whole application.  Rendering, storage, and collection would all have
to change.

Why don't you calculate bytesPerTenSeconds, bytesPerMin (and maybe
megabytesPerHour) with no rollup (i.e. only one retention rate) and store
them in 3 separate .wsp files? If your data source can't produce that data,
I feel for you, but it's probably a lot easier to do some simple math
before sending the data than re-writing the entire Graphite storage system
for an edge case like this.

-Nick

On Mon, Feb 27, 2012 at 4:11 AM, magec <question148743@xxxxxxxxxxxxxxxxxxxxx
> wrote:

> Question #148743 on Graphite changed:
> https://answers.launchpad.net/graphite/+question/148743
>
> magec posted a new comment:
> I think, the summarize approach is not enough. Now I'm experiencing
> another issue and I think there whould be no way of solving it. When
> carbon writes the points into whisper it uses the timestamp just to know
> what "metric slot" the data should be stored into and, as far as I know,
> the timestamp is then discarded.
>
> If a proper derivative function is to be implemented it should have into
> account the time interval between every two points. The summarize
> approach will still have this problem.
>
> My question is: Is the timestamp discarded as I say? There is another
> backend to store data, Does it discard the timestamp information as
> well? Whouldn't it be possible to store an offset for every point in the
> whisper file with the "drift" of the metric so a better derivative
> function can be implemented?
>
> I think this issue should be well resolved cause this case is so common,
> counters in network appliances, cpu, memory, etc...
>
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