[rrd-developers] Add `FETCH' command to rrdcached

[Florian Forster]

Hi Tobi,

On Wed, Apr 08, 2009 at 06:08:18PM +0200, Tobias Oetiker wrote:
> > > a) looking at the patch I see that the flushing operation is
> > >    included in rrd_graph (this is not new).
> >
> > It is? I can't find it:
> > -- 8< --
> >  octo at leeloo:~/rrdtool-trunk.git $ git branch | fgrep '*'
> >  * ff/rrdc_fetch
> >  octo at leeloo:~/rrdtool-trunk.git $ grep -i flush src/rrd_graph.c || echo "No match"
> >  No match
> > -- >8 --
> >
> > Anyways, the changes made to ?rrd_{fetch,graph}.c? were meant for
> > discussion only, and I think we've reached the consensus that including
> > a daemon address on a per-file level is preferable to the existing code.
> 
> well it is in the official repo ... dont know about the git mirror
> though ...

I'm confused. Of course the call to ‘rrdc_flush’ is in the SVN
repository – my patch *removes* it. So after applying the patch, the
call to ‘rrdc_flush’ is gone, which is exactly what you expected and
presumable wanted to have..?

> >    Also, this keeps magic
> >    out of `rrd_fetch' and keeps the distinction clear and easy:
> >
> >     * ?rrd_fetch? and ?rrd_fetch_r? are for local file access.
> >     * ?rrdc_fetch? is for remote file access.
> 
> hmmm the 'problem' is that through this only graph will benefit and
> fetch will not, causing all code that uses both fetch and graph to not
> be able to use the remote data access ...

I don't see the problem: Previously, when a daemon address was given,
‘rrd_fetch’ sent a ‘FLUSH’ command then then read the local file. With
the proposed patch, ‘FLUSH + local file’ is substituted by ‘FETCH’ only.
Either way, the user gets up-to-date, albeit not from a local file in
the latter case. In either case users or programs can configure the
daemon using the environment variable.

Regards,
-octo
-- 
Florian octo Forster
Hacker in training
GnuPG: 0x91523C3D
http://verplant.org/
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