[opensource-dev] User Story: Improved Cache

Tateru Nino tateru at taterunino.net
Sun Sep 19 12:53:59 PDT 2010

On 20/09/2010 3:49 AM, Oz Linden (Scott Lawrence) wrote:
>    On 2010-09-19 10:21, Tateru Nino wrote:
>> I believe he was referring to the fact that a UUID does not always refer
>> to the same inworld object. There are instances where an object UUID
>> will be used more than once.
> Those would be bugs, by definition.
Well, it pretty much happens when a sim is down. When that happens, 
objects being instantiated in other sims may be given the same UUIDs as 
objects that are in another sim that is not presently online on the 
grid. When the sim comes back up, the clash in UUIDs is noted, and new 
UUIDs are chosen for any conflicts in that sim. It's been around for 
quite some time, and is a particular pest for someone who wants to refer 
to a server-object by UUID in - for example - an inworld or outworld 
script. Common workarounds involve using an external server for the 
object to register its current UUID to.

That's been the case since 2005, but being a server-side issue is 
probably out-of-scope here.

As far as textures go, I believe the way they are handled as assets is 
different to instantiated objects, and that they do not suffer from the 
same issue. Of course, if log in to more than one grid, there's no 
guarantees that a texture with a given UUID in your cache is the same 
texture that you're supposed to be getting. While the space for texture 
UUIDs is very large, they're only unique to a specific grid and clashes 
will inevitably occur over time.

Tateru Nino

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