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[Michael Leinartas <question205821@xxxxxxxxxxxxxxxxxxxxx>]

Question #205821 on Graphite changed:
https://answers.launchpad.net/graphite/+question/205821

Michael Leinartas requested more information:
While there's a case for storing future data, I dont think there'd be a
way to make this sanely work with whisper as it's designed. Since these
files are fixed size and written with rolling-over offsets, writing to
the future will overwrite data in the past. Ex: you have a whisper file
with 30 day retention - if you write data 1 day in the future, you'll
overwrite the data from 30 days ago. It's more confusing if you have
multiple retentions: Say you have a whisper file with a 1 week and then
1month archive. If you write a point 1 day in the future, you're
overwriting data from 7 days ago *and* from 30 days ago. While each of
these archives will still be consistent when fetched (fetches only ever
return data from a single archive - they dont get combined) this is
quite unintuitive in my mind.

I do agree that the manipulation of from/until times as is can be quite
confusing from a user perspective. I think though that any change to the
existing behavior (and this would include the future case outlined in
the original question) can be handled by the webapp. Currently the
webapp requests the datestamp the user provides (via from= and until=
parameters) but then renders only based on the time range of data it
returns. It can instead use the requested datestamps for the graph width
and render the requested data within that.

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