[Opensim-users] Are unused assets deleted? (Fred Beckhusen)

[Ethan Gardener]

Thank you for your reply, melanie.  Reasoning on the problem, I've come to agree that deleting unused assets is an extremely difficult problem, perhaps not worth solving.

However, everything I've ever learned about databases says that it's a bad idea to just look at the cost of the disks.  The cost of *accessing* the data (with acceptable performance) goes up exponentially with the size of the dataset.  There is a solution which I think practically returns the problem to just counting the cost of the disks:  Cache the asset server.  The actual asset server which never deletes anything can then be very slow, with all regularly used assets served from the much faster cache.  

I'm almost certain Second Life implemented such a cache years ago.  I remember when I logged in there after a long absence, things which I'd made or which were old-style took minutes to rez.  I don't ever remember seeing such an effect in InWorldz, so I think it's possible InWorldz didn't have such a cache.  

Does OpenSim cache the asset server?  I'm thinking it doesn't, because some grid techs will tell you the first thing they did for their new grid was rewrite the asset server.  Of course, maybe it does now but didn't when they were getting started.  I'd be interested to know.

On Sun, Aug 12, 2018, at 6:08 PM, Melanie wrote:
> There isn't a real reason to expend that sort of time and effort on 
> cleaning assets. First off, for assets named in scripts, a heuristic is 
> used. It can't detect all assets with certainty and it will also have 
> false positives. Therefore, some things may break an some unused assets 
> will be kept. However, and that is the more important part, even a large 
> commercial grid operating for years accumulates assets that still easily 
> fit on a modern hard disk. Furthermore, if one disk fills up another can 
> be added. So, for many grids I know and certainly for myself, the mantra 
> is "disk space is cheap" and that way there isn't a risk of breaking 
> users' creations. Deduplicating asset systems like fsassets make this 
> even more relevant, because most large assets are meshes and textures 
> that are uploade by many people, but are actually identical. 
> Deduplicating is a massive help there. At the end of the day, there is 
> only one way to remove a prim, even one without contents, completely. If 
> you rez a prim and then delete it, it will be taken off the region, 
> serialized and put into an asset to be put into your trash. So that is 
> not the solution. In fact, the only way to remove a prim from a region 
> without creating an asset is llDie(). It creates no copy. - Melanie ---- 
> On Sun, 12 Aug 2018 16:46:15 +0000 Fred Beckhusen <fred.b at mitsi.com> 
> wrote ---- 1. Are unused assets deleted? (Ethan A. Gardener) Dumping and 
> reloading breaks all Firestorm links to Outfits. Take a look at thi web 
> page at Wizardry and Steamworks (grimore.org/opensim/database/
> asset_cleaner) for a possible way to clean a db It uses PHP with OARS 
> and IARS to make lists of what to keep, then deletes the rest. Fred 
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