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[Question #228438]: Values written randomly differ from values read

To: graphite-dev@xxxxxxxxxxxxxxxxxxx
From: Michael Turner <question228438@xxxxxxxxxxxxxxxxxxxxx>
Date: Wed, 08 May 2013 16:31:19 -0000
Reply-to: question228438@xxxxxxxxxxxxxxxxxxxxx
Sender: bounces@xxxxxxxxxxxxx

New question #228438 on Graphite:
https://answers.launchpad.net/graphite/+question/228438

I don't understand why this is happening.  It's random, and not happening consistently.  Maybe it's a product of internal rounding, floats to int conversions, or something like that.

My aggregation method is "last" for this pattern.

I write the data to graphite here (the numeric value only):

D, [2013-05-07T15:05:00.871314 #49343] DEBUG -- : TS: 1367964300

I sleep for 60s in the code, and then I pull the last 10 data points:

D, [2013-05-07T15:06:00.885138 #49343] DEBUG -- : Result body was [{"target": "XXX.YYY.ZZZ.graphite.avail", "datapoints": [[null, 1367963820], [null, 136796388
0], [null, 1367963940], [1367964000.0, 1367964000], [null, 1367964060], [null, 1367964120], [null, 1367964180], [null, 1367964240], [1367964301.0, 1367964300], [null, 13
67964360]]}]

The null data points are fine, as I just didn't write anything there, but on the point I did write, the value is not the same as the one I wrote:

[1367964301.0, 1367964300]

Why is this value sometimes being incremented by 1.0?

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