[rrd-users] Fetch the time of the first entry

Simon Hobson linux at thehobsons.co.uk
Tue Jul 1 14:23:44 CEST 2014

Steven Sim <unixandme at outlook.com> wrote:

> my rrdtool first <rrdfile> command keeps returning different timing after each rrdtool update.
> Why is that so?
> Shouldn't it ALWAYS return the Unix time stamp for the first entry?

It's not a function I've used ...

The docs say it should return the first value entered. Once you've "filled" a data set, then it's going to give you the timestamp of the oldest available value - I'm not sure what it gives you for an RRD file that hasn't been "filled".
Here I'm using the term "filled" to mean you done enough updates that the whose database (or at least data series) has been filled with data and you are now losing older data to make way for the new data.

Have you looked at how the value is changing ? Does it by any chance advance at the same rate as the timestamp of your updates ?

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