[rrd-developers] RRD PostgreSQL extension

[Dustin Fisch]

Hm. Also a nice idea.

But the benefit I want to from the PostgreSQL extension is to use psql
as a network protocol and feeding the RRD database from data I have in
my PostgreSQL database.

The idea is to have a table with the following columns:
id BIGSERIAL,
name VARCHAR,
value DOUBLE,
history RRD

now I can use a trigger for the "value" column to update the history on
each update automatically.

And as almost all programming languages have a PostgreSQL driver, they
can would have a network-able RRD interface out of the box.

cheers
fooker


Anthony Johnson <ansoni at gmail.com> wrote:

> Just curious... couldn't you simply build or use one of the existing
> Database filesystems that work with Fuse?  Then you could mount a
> filesystem whose backend is Postgres.
> 
> http://sourceforge.net/apps/mediawiki/fuse/index.php?title=DatabaseFileSystems
> 
> 
> The postgres FUSE project seems to be dead, but these seem to be
> pretty simple to create.  This would mean that all existing tools
> such as Cacti would not need any changes and migrating to such a
> setup would require only a cp /olddirectory/* /sqlbackeddirectory/
> 
> I would hope that a database backed filesystem would also be able to
> take advantage of filesystem caches at the OS-level which might be a
> free performance gain.
> 
> Good luck,
> 
> Anthony
> 
> On Tue, Sep 11, 2012 at 7:44 PM, Dustin Fisch <fooker at lab.sh> wrote:
> 
> >
> >
> > Tobias Oetiker <tobi at oetiker.ch> wrote:
> >
> > > Hi Dustin,
> > >
> > > Yesterday Dustin Fisch wrote:
> > >
> > > > Hi,
> > > >
> > > > I am currently thinking about building an RRD extension for
> > > > PostgreSQL.
> > > >
> > > > The extension will provide a RRD data type which represents a
> > > > complete database and functions for all the existing functions
> > > > of the RRD tool, like create, update, first and graph...
> > > >
> > > > PostgreSQL has a nice API for LOB, which allows to store the
> > > > whole RRD database using the PostgreSQL file management.
> > > >
> > > > I already have taken a look to the RRD code. As far as I can
> > > > see, there are functions like rrd_create_r(...) which provides
> > > > the functionality I need for such an extension.
> > > >
> > > > The PostgreSQL LOB API currently provides a file descriptor for
> > > > the access to the data stored in the LOB.
> > > >
> > > > Unfortunately, it looks like the RRD API only allows the usage
> > > > of a filename.
> > > >
> > > > Is there any way to use a file descriptor instead of the
> > > > filename? Or is there any chance such a patch would be accepted?
> > >
> > > if done nicely, I'll be glad to integrate such a patch ... I guess
> > > you would have to compile without mmap support ...
> > I'm not sure about mmap. I think I have to try it.
> >
> > The plan for the patch is to refactoring the rrd_*_r methods by
> > moving out the real work of the method into something called
> > rrd_*_x. The only thing remaining in the original method are the
> > calls to rrd_open and rrd_close and the call to the new method.
> >
> > The new rrd_*_x methods will mirror the interface of there rrd_*_r
> > counterparts expect the filename parameter, which will be replaced
> > by the already opened rrd_file_t.
> >
> > >
> > > how would this pg integration work, would the rrd data be stored
> > > in a blob ? wouldn't this get read from disk entirely on every
> > > update and make things rather slow ?
> > Right. The idea is to store the RRD data in a BLOB.
> >
> > But I don't see any performance problem with this as a PostgreSQL
> > extension is allowed to work on the file backing the BLOB directly
> > using a file descriptor.
> >
> > This makes no difference to the way RRDtool currently works. Maybe
> > this allows to to use the current mmap code, too.
> >
> > >
> > > cheers
> > > tobi
> > >
> > >
> >
> > cheers
> > fooker
> >
> > --
> > http://lab.sh
> >
> > _______________________________________________
> > rrd-developers mailing list
> > rrd-developers at lists.oetiker.ch
> > https://lists.oetiker.ch/cgi-bin/listinfo/rrd-developers
> >
> >


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