Second Life Forums Archive - Perceived effects of server update

SuezanneC Baskerville

Forums Rock!

Join date: 22 Dec 2003

Posts: 14,229

05-27-2008 20:07

The gang of Linden are doing a server update in the next few days.

The update includes changes to how "single-use, temporary assets" are handled, among other things.
Here's and excerpt:

From: L-blog

* Changes to eliminate storage wasted by single-use, temporary assets. (Helps our asset server!)
* Introduced automatic sound playback throttling for scripts. (Should not affect existing well-behaved content, but should help reduce specific instances of griefing.)
* More specific IM-to-Email subject line: “Second Life - <name> has sent you a message”
* Corrected text encoding issues in classifieds.
* Addition of several metrics for tracking system failures. (Helps us fix more bugs.)
* Made viewer->simulator message queue length configurable at runtime (Helps address teleport failures.)
* Several changes to reduce load on central databases.
* Several Havok4 fixes. (Will be listed later tonight.)

Full post at http://blog.secondlife.com/2008/05/27/second-life-122-server-update-tue-527-thu-529/

I'm wondering if anyone will notice any changes resulting from the first item in the list.

_____________________

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So long to these forums, the vBulletin forums that used to be at forums.secondlife.com. I will miss them.

I can be found on the web by searching for "SuezanneC Baskerville", or go to

http://www.google.com/profiles/suezanne

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http://lindenlab.tribe.net/ created on 11/19/03.

Members: Ben, Catherine, Colin, Cory, Dan, Doug, Jim, Philip, Phoenix, Richard,
Robin, and Ryan

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Sindy Tsure

Will script for shoes

Join date: 18 Sep 2006

Posts: 4,103

05-27-2008 20:44

Sounds like the sim won't send rezzed temp-on-rez objects to the asset server.

Fine by me. Do you have an example of this being a bad idea?

SuezanneC Baskerville

Forums Rock!

Join date: 22 Dec 2003

Posts: 14,229

05-28-2008 20:17

I just had a feeling that this server code release hadn't been tested long enough. It had only been out on the Beta, umm, Preview grid for a week or so before the announcement that prompted this thread.

I picked the inventory system change as the place to scrutinize because the inventory system has been unreliable for years now.

Turns out the first part of the changes to present problems was the sound throttling.

There's still time for some bad consequence - or possibly a noticeable improvement - to occur from the change in inventory behavior.

_____________________

-

So long to these forums, the vBulletin forums that used to be at forums.secondlife.com. I will miss them.

I can be found on the web by searching for "SuezanneC Baskerville", or go to

http://www.google.com/profiles/suezanne

-

http://lindenlab.tribe.net/ created on 11/19/03.

Members: Ben, Catherine, Colin, Cory, Dan, Doug, Jim, Philip, Phoenix, Richard,
Robin, and Ryan

-

Ceera Murakami

Texture Artist / Builder

Join date: 9 Sep 2005

Posts: 7,750

05-28-2008 20:23

I know the second one, the throttle on sound sources, completely trashed a lot of perfectly innocent wildlife and natural ambient sound sources...

_____________________

Sorry, LL won't let me tell you where I sell my textures and where I offer my services as a sim builder. Ask me in-world.

Argos Hawks

Eclectically Esoteric

Join date: 24 Jan 2007

Posts: 1,037

05-28-2008 20:30

I read somewhere else (I think it was in the comments to that blog post) that the fix you are referring to would only affect attachments. Apparently in the old code, wearing an attachment would create a copy that did not get deleted from the asset server when the item was removed.

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Step 1: Create virtual world
Step 2: ???
Step 3: Profit

SuezanneC Baskerville

Forums Rock!

Join date: 22 Dec 2003

Posts: 14,229

05-28-2008 20:39

From: Argos Hawks

the comments to that blog post)

I think there weren't any comments at the time I read it.

Attachments, eh? We've been having lost inventory connected with detaching attachments, or something like that, in the last month or two, is that right?

_____________________

-

So long to these forums, the vBulletin forums that used to be at forums.secondlife.com. I will miss them.

I can be found on the web by searching for "SuezanneC Baskerville", or go to

http://www.google.com/profiles/suezanne

-

http://lindenlab.tribe.net/ created on 11/19/03.

Members: Ben, Catherine, Colin, Cory, Dan, Doug, Jim, Philip, Phoenix, Richard,
Robin, and Ryan

-

Malachi Petunia

Gentle Miscreant

Join date: 21 Sep 2003

Posts: 3,414

05-28-2008 23:44

From: SuezanneC Baskerville

Attachments, eh? We've been having lost inventory connected with detaching attachments, or something like that, in the last month or two, is that right?

Correct.

However, it is conceivable that the old process was roughly:
1. dup the inventory item item into a new UUID
2. save the new UUID in asset database
3. attach new UUID
4. detach item
5. attempt to write new UUID in place of original
6. database fails
7. original UUID contents are corrupted

If this was how it was done, and the new method skips the "copy constructor" of (1) it is possible that a change in method might reduce inventory corruption.

Then again, I made most of this up and could well be mistaken.

Kitty Barnett

Registered User

Join date: 10 May 2006

Posts: 5,586

05-29-2008 10:16

From: someone

On logoff, attachment state is serialized as assets. On login it is reconstituted into the in-memory representation of the sim. At this point, the serialized copy of the data is unnecessary and will never be used again (the single reference to it is now discarded), so it can be purged from the asset store and save us precious storage space.

Due to the complexity of the system (e.g. you can attach items from the library, different code paths, etc) it's required several iterations, and not all the kinks are out yet. The assets are NOT currently being purged - instead they're moved into a holding area that is checked as a fallback if a read from the primary store fails. We'll know the system is working correctly when there are no reads from the holding area.
After the most recent update we're watching carefully to see if we've caught all of the cases. Eventually we'll be able to flip the code from "move" to "delete" mode and purge the holding area, but of course we're paranoid.

(Quoted from SLdev)

Addition:

From: someone

Minor clarification - it it matches the design I saw, the purge happens at logoff after successfully serializing the new version, and only if no copy of the object was made during the usage session.
There's no room for data loss in the event of a crash.

Perceived effects of server update
SuezanneC Baskerville Forums Rock! Join date: 22 Dec 2003 Posts: 14,229	05-27-2008 20:07 The gang of Linden are doing a server update in the next few days. The update includes changes to how "single-use, temporary assets" are handled, among other things. Here's and excerpt: From: L-blog * Changes to eliminate storage wasted by single-use, temporary assets. (Helps our asset server!) * Introduced automatic sound playback throttling for scripts. (Should not affect existing well-behaved content, but should help reduce specific instances of griefing.) * More specific IM-to-Email subject line: “Second Life - <name> has sent you a message” * Corrected text encoding issues in classifieds. * Addition of several metrics for tracking system failures. (Helps us fix more bugs.) * Made viewer->simulator message queue length configurable at runtime (Helps address teleport failures.) * Several changes to reduce load on central databases. * Several Havok4 fixes. (Will be listed later tonight.) Full post at http://blog.secondlife.com/2008/05/27/second-life-122-server-update-tue-527-thu-529/ I'm wondering if anyone will notice any changes resulting from the first item in the list. _____________________ - So long to these forums, the vBulletin forums that used to be at forums.secondlife.com. I will miss them. I can be found on the web by searching for "SuezanneC Baskerville", or go to http://www.google.com/profiles/suezanne - http://lindenlab.tribe.net/ created on 11/19/03. Members: Ben, Catherine, Colin, Cory, Dan, Doug, Jim, Philip, Phoenix, Richard, Robin, and Ryan -
Sindy Tsure Will script for shoes Join date: 18 Sep 2006 Posts: 4,103	05-27-2008 20:44 Sounds like the sim won't send rezzed temp-on-rez objects to the asset server. Fine by me. Do you have an example of this being a bad idea?
SuezanneC Baskerville Forums Rock! Join date: 22 Dec 2003 Posts: 14,229	05-28-2008 20:17 I just had a feeling that this server code release hadn't been tested long enough. It had only been out on the Beta, umm, Preview grid for a week or so before the announcement that prompted this thread. I picked the inventory system change as the place to scrutinize because the inventory system has been unreliable for years now. Turns out the first part of the changes to present problems was the sound throttling. There's still time for some bad consequence - or possibly a noticeable improvement - to occur from the change in inventory behavior. _____________________ - So long to these forums, the vBulletin forums that used to be at forums.secondlife.com. I will miss them. I can be found on the web by searching for "SuezanneC Baskerville", or go to http://www.google.com/profiles/suezanne - http://lindenlab.tribe.net/ created on 11/19/03. Members: Ben, Catherine, Colin, Cory, Dan, Doug, Jim, Philip, Phoenix, Richard, Robin, and Ryan -
Ceera Murakami Texture Artist / Builder Join date: 9 Sep 2005 Posts: 7,750	05-28-2008 20:23 I know the second one, the throttle on sound sources, completely trashed a lot of perfectly innocent wildlife and natural ambient sound sources... _____________________ Sorry, LL won't let me tell you where I sell my textures and where I offer my services as a sim builder. Ask me in-world.
Argos Hawks Eclectically Esoteric Join date: 24 Jan 2007 Posts: 1,037	05-28-2008 20:30 I read somewhere else (I think it was in the comments to that blog post) that the fix you are referring to would only affect attachments. Apparently in the old code, wearing an attachment would create a copy that did not get deleted from the asset server when the item was removed. _____________________ Step 1: Create virtual world Step 2: ??? Step 3: Profit
SuezanneC Baskerville Forums Rock! Join date: 22 Dec 2003 Posts: 14,229	05-28-2008 20:39 From: Argos Hawks the comments to that blog post) I think there weren't any comments at the time I read it. Attachments, eh? We've been having lost inventory connected with detaching attachments, or something like that, in the last month or two, is that right? _____________________ - So long to these forums, the vBulletin forums that used to be at forums.secondlife.com. I will miss them. I can be found on the web by searching for "SuezanneC Baskerville", or go to http://www.google.com/profiles/suezanne - http://lindenlab.tribe.net/ created on 11/19/03. Members: Ben, Catherine, Colin, Cory, Dan, Doug, Jim, Philip, Phoenix, Richard, Robin, and Ryan -
Malachi Petunia Gentle Miscreant Join date: 21 Sep 2003 Posts: 3,414	05-28-2008 23:44 From: SuezanneC Baskerville Attachments, eh? We've been having lost inventory connected with detaching attachments, or something like that, in the last month or two, is that right? Correct. However, it is conceivable that the old process was roughly: 1. dup the inventory item item into a new UUID 2. save the new UUID in asset database 3. attach new UUID 4. detach item 5. attempt to write new UUID in place of original 6. database fails 7. original UUID contents are corrupted If this was how it was done, and the new method skips the "copy constructor" of (1) it is possible that a change in method might reduce inventory corruption. Then again, I made most of this up and could well be mistaken.
Kitty Barnett Registered User Join date: 10 May 2006 Posts: 5,586	05-29-2008 10:16 From: someone On logoff, attachment state is serialized as assets. On login it is reconstituted into the in-memory representation of the sim. At this point, the serialized copy of the data is unnecessary and will never be used again (the single reference to it is now discarded), so it can be purged from the asset store and save us precious storage space. Due to the complexity of the system (e.g. you can attach items from the library, different code paths, etc) it's required several iterations, and not all the kinks are out yet. The assets are NOT currently being purged - instead they're moved into a holding area that is checked as a fallback if a read from the primary store fails. We'll know the system is working correctly when there are no reads from the holding area. After the most recent update we're watching carefully to see if we've caught all of the cases. Eventually we'll be able to flip the code from "move" to "delete" mode and purge the holding area, but of course we're paranoid. (Quoted from SLdev) Addition: From: someone Minor clarification - it it matches the design I saw, the purge happens at logoff after successfully serializing the new version, and only if no copy of the object was made during the usage session. There's no room for data loss in the event of a crash.

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Perceived effects of server update