[rrd-developers] [PATCH] rrd_open and rrdcached

Tobias Oetiker tobi at oetiker.ch
Wed Oct 22 22:35:04 CEST 2008

Today kevin brintnall wrote:

> On Wed, Oct 22, 2008 at 11:37:25AM +0100, Daniel.Pocock at barclayscapital.com wrote:
> > rrdcached makes some calls to access and stat, which don't work for my
> > virtual filesystem abstraction.
> >
> > This patch:
> Daniel,
> I am OK with this idea, but there are a few implementation details that
> need fixing.
> Should the functions really be marked as RRD_DEPRECATED in "rrd.h"?  The
> same question applies to other functions you introduced in that section of
> the header (i.e. rrd_notify_row).
> rrd_daemon.c must #include "rrd_tool.h" instead of "rrd.h"..  Otherwise,
> it won't get the rrd_{access,stat} prototypes from the internal-only
> section of rrd.h.
> In bindings/perl-shared, need to add "-std=c99" to the build args in order
> to use "restrict" keyword in the rrd_{access,stat} prototypes...  Or, we
> can remove "restrict" from the prototypes (I'm not sure how portable
> "restrict" is).

using c99 in rrdtool is fine, the public headers should not use
c99isms though, since the world is not only gcc ...

> > I'm also coming up against similar issues with Ganglia - gmetad wants to
> > know if the RRD files already exist on disk, even though they only exist
> > in my virtual back-end.  To deal with that, I'm thinking of adding some
> > methods to the RRD API so that applications can do things like browsing
> > the directory of RRDs.
> We'll have to find a way of doing it without pushing any changes into the
> application (i.e. Ganglia) ...  There are zillions of custom RRD
> applications out there that expect a file to exist.  We can't expect them
> to adapt.
> A place-holder file makes sense... possibly empty, or possibly with enough
> information to locate it in the striped file.

there was this idea to have 'placeholder' files which would even
allow todo fancy things like having rrdtool store data in an sql
database for those who are so inclined.


Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
http://it.oetiker.ch tobi at oetiker.ch ++41 62 775 9902 / sb: -9900

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