[Opensim-dev] About Processing on Assets Table (Discussion #2057)

[Sean Dague]

Michael Wright wrote:
> If it is creating a new asset every time a user simple attaches/detaches a prim, then it is something that should be looked at. As I don't think it should be happening.
> 
> But as Melanie explain in the mantis issue, if a user makes a change, like changes the attachment point, then this does result in a new asset being created. Assets are sharable and as Melanie explained you never know who else has a refference to that asset. So you can't update it, as it would effect everyone who is using that asset.
> 
> There has been talk in the past about lots of different possible changes to the asset system. But any big changes would need a lot of changes deep in the core of opensim. 
> 
> "Tao YANG (GMAIL)" <thomas.tao.yang at gmail.com> wrote: Hi everyone,
> 
> I discussed this issue a little with melanie in Mantis #2057.  Thanks melanie!
> Even though #2057 was turned into resolved, not fixable,
> I still have some questions and want to discuss it with you all.
>   
> Please allow me describe this issue again in brief.
> I first noticed the problem when I was testing attachment using MySQL,
> that "assets" table increased without limit if you attach/detach repeatedly.
>   Reading source code, there is no real deleting, updating, but adding on the table.
> So I report it in #2057 and tried to attach a patch.
> And melanie explained the reason why assets cannot be updated or deleted.
> 
>  The point could be whether the records in assets table can be updated or deleted.
> 1. Is it good technically that asset table is increasing without any limit?
>  2. In case of attachment, for example,
>    if an attached object is not shared with others, after modifying or when
>    detaching it, should we still create a new record in assets table, letting
>    the previous one become garbage and never be used?
>     I think the process on attachment should be improved.  But that could be based
>    on how assets work.

Also remember, assets being immutable is a function of the protocol.
The client will never fetch an asset that it already has, so if you were
to ever update an assets content you would need to force all viewers to
clear their caches and restart their viewers.  This is a protocol
optimization which may be good or bad, but it out of our control.

	-Sean

-- 
Sean Dague / Neas Bade
sdague at gmail.com
http://dague.net


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