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Can anybody explain to me why I get different values when I fetch from my rrd-db than what I filled it with.

Here are the commands:

a. Create database

rrdtool create temperature.rrd --step 300 -b 1374150100 \
 DS:temp:GAUGE:300:N:N \
 RRA:AVERAGE:0:1:5

b. Fill with data

rrdtool update temperature.rrd \
 1374150400:6 \
 1374150700:8 \ 
 1374151000:4 \ 
 1374151300:4

c. Fetch data

rrdtool fetch temperature.rrd AVERAGE --start 1374150099 --end 1374151301

Output:

                           temp

1374150300: 6.0000000000e+00
1374150600: 7.3333333333e+00
1374150900: 5.3333333333e+00
1374151200: 4.0000000000e+00
1374151500: -nan

I fill the database in the exact period with data. I have no idea why it displays 7.3 and 5.3?! Did I missed something?

Steven V
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appsthatmatter
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1 Answers1

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OK, I got it. The problem is, that the start time does not fit to the step interval. As you can see in the output, the steps begin with ...300, then ...600 and so on. I filled the data with ...400, ...700 etc. So the solution is to set the values in the correct step interval and then it works

appsthatmatter
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