[sldev] Fun with 010 Editor + some random tought about texture cache

[SignpostMarv Martin]

Argent Stonecutter wrote:
> On 2008-06-09, at 14:35, SignpostMarv Martin wrote, regarding 
> Laurent's suggestion for a sim cache:
>> referenced by name or sim UUID ?
>
> I would think that since it's a cache it doesn't really matter. If the 
> UUID is well distributed it could use it directly, or the sim name, or 
> a hash of the sim name. It probably doesn't even matter much if 
> there's sim name collisions.
Clarification: VFS references, or LLSD list of assets UUIDs ?

Problem 1) Sim gets renamed. Does the UUID stay the same ? Use case: 
metaverse development company X gets hired to develop a sim for company 
Y.  company X owns the sim while the work is being done (with an 
inconspicuous name so as to avoid PR issues), company X then transfers 
ownership of sim to company Y. Company Y has name of sim changed. No 
assets within the sim are changed.

Problem 2) beta grid vs main grid (and LL's SL vs OpenSim). Use case: 
aside from visitors, region A is identical on both grids. region B has a 
few differences (one or two buildings weren't yet erected at the time 
the beta grid snapshot was made). region C is completely different- few 
if none identical assets.

Problem 3) region being withdrawn. Use case: short term events, like 
Burning Life/ SL Birthday


With problem 1, if the cache is references by name, then you just 
duplicated your effort. if the cache references by UUID, then the region 
UUID should remain the same, lest the same duplicated effort issue crops up.

With problem 2, in case C, you'll have the cache reference bloat to 
twice the size it needs to be.

Garbage collection:
Problem 2)  If regions have the same identifier, when the viewer 
connects to one grid then the other, you'll either have twice the amount 
of assets loaded than is needed, or you'll have half of the assets going 
missing and needing to re-download. If identical sims on seperate grids 
have the same content, but different UUIDs, should such region-based 
caching make allowances for that ? Also, because of case C in problem 2, 
such a region-based referencing mechanism should probably have the grid 
the region is attached to as a root reference.

Problem 3) Assuming the grid-based root reference is in place, I shall 
illustrate a conversation between the viewer and server that solves 
problem 3:
Viewer) (upon login) "Does region x exist within the grid ?"
Server) "Yes" (load/fetch referenced assets). "No" (remove region 
reference files)

The server's response of "Yes"/"No" should not be based upon credentials 
(e.g. whether or not a Resident can access the given region should not 
be taken into account).


~ Marv.
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