What exactly does clearing the cache do?

Clearing the cache seems to be the standard advice given to cure a multitude of ills. It is the standard advice for inventory loss. My modeling trainers advise us to clear the cache before the start of any fashion show.

I assume that the cache stores information about your inventory. I assume that clearing the cache forces a resynchronization with the central database. This doesn't seem to occur all at once, but on an as needed basis as I open inventory folders or force a search.

I understand the need to resynchronize, especially if inventory appears lost. But what other benefits are there to doing that? I don't see how it speeds things up. In fact it seems to slow inventory retrieval down as the inventory only seems to get resynchronized on an as needed basis. I'm puzzled why my modeling trainers would recommend clearing the cache before every show.

Can someone shed light on what I may be missing here?

Other than as a way to make sure any corrupted junk is gone, it's not going to have any magical properties. If you're going to a new place, it might seem to give a little bit of a speed boost, because the viewer doesn't have to spend time deleting old cached stuff to make room for new.

yup that's about it.

It has more impact on the speed of marginal computers. I know. I just upgraded from a marginal computer, and I routinely used to clear the cache with every log off. Now I don't notice much difference.

If you have cleared your cache and want to spend a few minutes resyncing so your inventory is "good to go", open up your inventory and search for some innocuous character like "a" or a space, and sit there and watch your viewer download inventory information until it's done. Repeat with more characters as needed.

Yeah I know that doesn't answer the question but it can be handy from time to time.

mmm? I thought that the cache held items in your inventory. Why would going to a new place matter? Am I missing something here? Does the cache hold more than just your inventory?

Yes, the bulk of it is textures.

Yeah, so if I go to Sim X and wander around, forcing my client to download all the textures on the sim, then clear cache and relog, won't my client have to re-download all those textures again? Why do people claim that this IMPROVES speed? Wouldn't it decrease speed?

Perhaps people are saying that it improves speed if you go somewhere ELSE, not back to the same place. *shrug*

I know there are issues with cached textures and such not being any faster than downloading them anew, once you reach a certain point - even slower if you have too many files in your cache. That's why they reverted back to the current cap on maximum cache size after they played with allowing it to be much larger for a release or two.

It doesn't seem to speak well of the SL viewer's cache management strategy, whatever that might be.

Yes, that was I was getting at with "a new place". If you tend to frequent the same places (or even different places where you'll be running into a lot of the same textures), you would be defeating the whole point of a cache by dumping it!

I wonder if thre's a way of reading what your cache usage level is?

it's a directory on your HD so i'd say you propably could see how large the directory is.

It forces your SL client to re-get everything from the various servers. Just the act of fresh requests will sometimes result in lost items re-appearing in your inventory.

Part of the problem is that there's not really a good way to combine multiple textures into a single file so SL puts every one in its own separate file - on my system now, the textures cache has over 13,000 files in it. OS' aren't really good at dealing with directories this ginormous and it takes a lot longer than you'd think to get at one of the cached textures. Then there's the issue that textures in the cache are compressed so any time SL wants one, it's got to decompress it (again) before using it.

If your machine isn't very fast or the disk your cache is on is already busy due to you being low on memory or having other stuff in the background, going to your local cache for a texture can seem slower than asking SL for a copy of it.

wait, I thought cache was just that, like in your internet browser, the bits and pieces of garbage you have downloaded to view pages.. which we all know you gotta flush from time to time or else your net viewing is slowed...

The inventory reference you speak of has me curious now...

the inventory is stored on the asset server
(which isn't much of an asset most days and doesn't serv for much but headaches)
what you have in your cache is links to that information.
and every texture you've seen - -even if full alpha or behind another prim.
and every animation you've played
and every animation people around you have played
and every TP you've made
and the avatar info for everyone you've seen - even if behind a prim
-everything within your draw distance since you last cleared, or until it's overwritten

basically it IS like a web cache - all the little bits of garbage stored on your computer.
with LL's issues with memory storage, retreival, and leaks, clearing cache is probably aa good thing now and again

Nicely put!

I might add that you can think of it as a closet full of stuff. If it is loaded with textures and such.
And if you decide to go shopping at a new store, you will probably have to endure all of the new textures loading...but in order for them to load, your computer has to "make space" for them in the closet by pulling out stuff that you are not using at the moment and storing it on your hard drive.
This process of "making space" takes longer then normal because the computer is doing extra tasks now.

Also, if you crash for some reason, the cache sometimes gets corrupted so the next time that you log in, the computer will see the bogus cache and fail to log you in correctly.



Best thing to do is:

If you crash for some reason and can't get back in ...clear cache and try again.

If you are a heavy shopper and like to go to tons of differenrt stores...clear cache from time to time and you will see an improvement in performance.

When the techno Wiki person tells you to clear your cache and try again its basically technical jargon for ...


"heck I don't know what the hell is wrong with it - Its your computer - just try this and leave me alone."

Simple matter really, your cache holds textures. Your inventory is made of of many items that are textures. What the OP is asking, and the answer already given, but perhaps not explained quite right, is you have so much space designated to store textures on your computer. Thus, if the cache is full, each new texture will need to replace something in the cache, so yes, the cache must delete something.

You will notice this full state if your TP'ing to a new location and your grey for an extended period of time, etc. Clear the cache and your good to go again. I do it frequently on my machine.

Hope this helped a little.

I just noticed that under the Advanced menu there is an item called "Clear Group Cache". How does this differ from the "Clear cache" found under the network tab of the Preferences menu?

It's only for group information (roles etc.) and it only lasts for the current login. Clearing it's only rarely useful, if the database borks.