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

[Martyn Russell <martyn lanedo com>]

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.

-- 
Regards,
Martyn