[rrd-users] api for iterating over single rows in a rrd file

[Plamen Dimitrov]

Hi rrdtool users!

As part of my google summer of code project with Ganglia I'm developing an
R package that imports the values from an RRD file into vectors in R
(without exporting to csv, xml or other intermediate format first). I'm
using the rrdfetch api to do this. Here is a working prototype:

https://github.com/pldimitrov/Rrd


Wnile this seems to work fairly well, it struck me that in a scenario when
I'm only interested in reading one row at a time (e.g. to compare values
from many RRDs simultaneously) , the rrdfetch code would need to go through
all error/sanity checks, find the RRA we want and seek to the desired
location in the file at each iteration.

I know the use of the internal rrd_read, rrd_seek, rrd_open, etc...
functions is not encouraged so I'm wondering what might be a good solution.
Ideally, it would be useful to have something that iterates one row at a
time, reads and caches the data.

Does anything like this already exist?  Would you agree it makes sense to
have this in addition to rrdfetch?

Regards,
Plamen
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