Re: [Tracker] miner-fs, files update and user metadata

[Adrien Bustany <abustany gnome org>]

On Wed, 12 May 2010 08:58:49 +0100, Martyn Russell <martyn lanedo com>
wrote:
> On Wed, 2010-05-12 at 00:03 +0200, Michele Tameni wrote:
> > Hi all, 
>
> Hi,
>
> > I think i've found a big problem and i want share my concern with you
> > all.
> >
> > The use case:
> > I save a photo ( photo.tif ) in my home directory, then miner-fs
> > extract metadata from the file and save it to tracker. Ok wow, all
> > great. I open my shiny Photo apps, i see my new file, and i assign a
> > new title (nie:title) to it. then i open photo.tif with gimp, cropt
> > it, set saturation etc, save the file. miner-fs see the modification
> > so, reindex the file... oops my title are gone... and with it every
> > other user entered metadata.
> >
> > I don't think this is expected, at least for the user.
> >
> > I found this issue trying to get
> > http://live.gnome.org/Tracker/Discussion/DirectNotification working.
> > Same problem here... every metadata wrote by the application who
> > creates the file are gone after the miner-fs analyze the file.
> >
> > miner-fs add a "drop graph....." before the insert query, and as frade
> > told me isn't trivial to remove.
> > Is this expected? any idea on how to work around or fix it?
>
> Ivan is right. It isn't simple to fix. We have known this would be a
> limitation for a while. Quad store can help here, but we haven't elected
> to implement that fully yet.
>
> The main issue here is that we have no way of knowing what was inserted
> by miner-fs and what was inserted by another application and I just mean
> for additional properties. If you store something like nie:title which
> is quite well used, miner-fs will just re-insert the nie:title found in
> the file's metadata. If the nie:title was written back to the file, then
> that partially solves this, however, storing multiple titles for each
> application is not something we can do without quad store.

Yeah actually this is showing up now as a severe limitation :/ I've been
having the same problem with my web miners. I have strictly no idea on how
hard quad store is to implement though...

Cheers

Adrien