[rrd-users] Fetching from the beginning of an RRD file

Travis Spencer travislspencer at gmail.com
Sun Mar 4 00:19:47 CET 2007

On 3/3/07, Alex van den Bogaerdt <alex at ergens.op.het.net> wrote:
> Questions you need to answer:
> Which RRA should be selected, in different cases?

Why not use RRA zero as in rrd_first when no RRA index is given?

> Example: what
> if no resolution is mentioned,

Then do like rrd_fetch and use a resolution of one.

> what if an existing resolution is
> mentioned,

Then set the step value to that unless it's less than one.  In that
case, return an error.

> what if a resolution is mentioned which is not available?

Again, do like rrd_fetch and attempt to find the best match.

> You also say: "I'm only interested in knowing the oldest time stamp"...

Let me clarify.  I would like to add a new token to SpecialToken
called "begin" or "first" that will allow the user to specify that
they would like processing to begin with the oldest time.  I would
like the patch to work with rrd_fetch, rrd_graph,rrd_xport, etc.

To do this, it seems that the changes would have to be made to
parsetime.c; however, parsetime doesn't have all the necessary
information (e.g., the RRD file, which CF, etc.), so things might have
to be handled elsewhere.

> So, similar to "rrdtool last", you are proposing "rrdtool first".

I am proposing a new special word that can be used as a start time; it
will be equated to the same time as that returned by rrd_first.

Perhaps we should move this discussion to the developer's list.



Travis Spencer

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