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

[Melanie]

Well, i guess the lindens are feeling the pain of an exploding asset 
data base by now.
On a grid that size, cleanup has to be a really slow process.

If I had to create such a process, i would probably procss small 
chunks of older assets, like 64 K worth of UUIDS

And send such a packet around the sims. Each sim would mark assets 
it references. When the packet comes back, all unmarked assets could 
be deleted. still a huge task, with tens of thousands of sims.

Melanie


Dahlia Trimble wrote:
> Thanks for the great explantion Melanie.
>  
> There was recently a discussion in sldev about asset garbage collection 
> in Linden Lab's servers. Apparently they search for references for all 
> assets in inventories, scripts, prim inventories, notecards, and 
> probably a few places I cant think of offhand. If an asset is found to 
> be unreferenced, the process will delete it. This was discussed as some 
> people were talking about obfuscating scripts to prevent copying, and a 
> linden was asking them not to do this as it could fool the asset garbage 
> collector into thinking an asset was unreferenced if the only reference 
> was in an obfuscated script.
>  
> The discussion was around May 19th and can be found in the sldev mailing 
> list archives.
> 
> On Mon, Jun 23, 2008 at 2:51 AM, Melanie <melanie at t-data.com 
> <mailto:melanie at t-data.com>> wrote:
> 
>     Yes. Assets are never given. The are always shared. You pass around
>     references, and permissions, names, descriptions, etc, apply to
>     those references only.
>     The viewer employs a transaction system to keep you from creating
>     references to arbitrary assets. If you could, you'd have a copy.
> 
>     Assets are immutable and implicitly shared. Any copy of an item
>     shares the asset with it's original.
> 
>     Texture, animation and sound are immutable items. There are no
>     changeable parts to the asset. All others get copied only when
>     changed (copy-on-write).
> 
>     So, at any given time, any asset can be referenced by any number of
>     people.
>     That is also the reason why no asset table cleanup is possible. You
>     just don't know if something is referenced. It's not just user
>     inventories, but also prim inventories and textures on prims, as
>     well as references to textures and sounds by UUID in scripts.
> 
>     So, asset naming is really a nonsense operation.
> 
>     Melanie
> 
> 
>     Mike Mazur wrote:
>      > Hi,
>      >
>      > On Mon, 23 Jun 2008 09:17:20 +0100
>      > Melanie <melanie at t-data.com <mailto:melanie at t-data.com>> wrote:
>      >
>      >> no. Assets are shared. If I give you an item, both items will refer
>      >> to the same asset. Who will have the right to rename?
>      >
>      > OK, let's see if I can understand this.
>      >
>      > If you give me an item, how many items are there? I assume if you
>     give
>      > me an item it's removed from your inventory and placed into mine.
>     There
>      > is only one reference to the asset.
>      >
>      > If you copy the item and give me a copy, what happens? The
>     reference is
>      > copied, while the asset is not? In that case we have two references,
>      > both referring to the same asset as you say.
>      >
>      > I guess if you copy an item and give me the copy, a new copy of the
>      > asset is _not_ made because that would clutter up the DB with
>     possibly
>      > thousands of identical assets?
>      >
>      > Thanks!
>      > Mike
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