[Opensim-dev] Proposal to eliminate the name, description and invType fields from the assets db table

[Sean Dague]

On Mon, Jun 23, 2008 at 03:59:14PM +0100, Melanie wrote:
> But, as far as I believe, if two people upload the exact same asset, 
> they should not be coalesced. I know I would not want that to happen 
> on my grid.
> 
> It would rob me, as a content creator, rob me of the ability to 
> determine whether they used my texture ID via script, or uploaded a 
> copy (which will cause the asset ID to be different).
> When using SHA hashing, the second uploader would be handed the same 
> ID, which, from my point of view, is not desired.

Let's seperate the use case you have, from the way you would implement
it on top of the existing system, which is wasteful in a bunch of ways.
The use case is to track inventory generations of the same asset.  I
think that would be much better done by adding a field to inventory
which is seeded on a new upload.  Inventory transfers/copies keep that
seed.

> Also, in the case of a hash collision (same hash for different 
> items), the uploader would be getting my texture instead of his, not 
> what he wants. He would basically be handed a full perm copy of a 
> texture I may have taken hours to create.

This isn't a viable attack unless you are the NSA, and have a lot of
years to burn (even with all published weakenings in SHA1).  So unless
you think the government is after your textures, don't worry about this
case.

> So, since duplicate prevention is not proper to attempt, hashing 
> seems pointless.

Making assets content addressable storage would be very useful,
especially for large scale installations.  To read up more on the entire
space, the wikipedia entry is pretty good:
http://en.wikipedia.org/wiki/Content-addressable_storage

    -Sean

-- 
__________________________________________________________________

Sean Dague                                       Mid-Hudson Valley
sean at dague dot net                            Linux Users Group
http://dague.net                                 http://mhvlug.org

There is no silver bullet.  Plus, werewolves make better neighbors
than zombies, and they tend to keep the vampire population down.
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