Re: [opensource-dev] HTTP asset fetching will soon be mandatory

[John Nagle]

On 10/30/2018 02:42 AM, Henri Beauchamp wrote:
> On Mon, 29 Oct 2018 17:59:13 -0400, Oz Linden (Scott Lawrence) wrote:
> 
>> On 2018-10-19 09:52 , Henri Beauchamp wrote:
>>
>>> My viewer has long been updated to make use of the newest HTTP fetching
>>> capabilities, but it also implements an automatic fallback to UDP fetches
>>> when HTTP ones fail (i.e. a texture failing to be served via HTTP is
>>> automatically re-requested using UDP).
>>
>> Better to requeue the request to HTTP after a suitable backoff (unless
>> of course you get a error that indicates that a retry would not work).
> 
> The fallback happens only for unrecoverable errors, of course (for other
> errors the HTTP retry policy is used)...

 I see 404 errors for capabilities frequently in Firestorm logs.
This shows up at region crossings as the viewer is fetching info
from the sim being entered. This may be a race condition, and
retrying may help.  Dropping to UDP probably isn't helpful.

 Asset fetches sometimes fail with 5xx errors indicating
problems with the CDN system caches.  When you ask the CDN
for an asset, you're really talking to (I think) a Nginx cache
server, which requests the asset from AWS. If the cache to AWS
request isn't filled quickly, you get a bogus error from the
cache system.  I've seen this occasionally.

 So I'd suggest retrying a few more times, at maybe 1 second,
on what look like hard errors on any URL that the sim gives you.
They're supposed to be valid URLs, after all.

John Nagle
Animats resident


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Re: [opensource-dev] HTTP asset fetching will soon be mandatory

[Henri Beauchamp]

On Mon, 29 Oct 2018 17:59:13 -0400, Oz Linden (Scott Lawrence) wrote:

> On 2018-10-19 09:52 , Henri Beauchamp wrote:
>
> > My viewer has long been updated to make use of the newest HTTP fetching
> > capabilities, but it also implements an automatic fallback to UDP fetches
> > when HTTP ones fail (i.e. a texture failing to be served via HTTP is
> > automatically re-requested using UDP).
>
> Better to requeue the request to HTTP after a suitable backoff (unless 
> of course you get a error that indicates that a retry would not work).

The fallback happens only for unrecoverable errors, of course (for other
errors the HTTP retry policy is used)...

> > Also, will AIS be made mandatory or will the non-AIS HTTP inventory
> > operations still be available ?  The reason for this question is that
> > AIS is still suffering failures from time to time, and the only solution
> > in that case is to disable it (or restart the sim)...
>
> The effort to disable the UDP inventory operations is separate;

Well, the effort should concentrate on making AIS3 operations reliable,
because so far, they never have been. I'm still getting 400 errors from
time to time, causing failures to update the inventory when they happen
(which in turn may cause rezzing failures, when it affects the COF).

As long as AIS3 is not 100% reliable, I would strongly advise *NOT* to
disable UDP inventory operations...

> but if there are UDP inventory operations you're using now that can be
> done through AIS, then you should be making those changes.

This has been implemented years ago in my viewer, so I'm not worried
about the code changes (already done) but only about the reliability
of inventory ops for the end user...

Henri.
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Re: [opensource-dev] HTTP asset fetching will soon be mandatory

[Oz Linden (Scott Lawrence)]

Sorry ... this ended up in my Junk folder somehow...

On 2018-10-19 09:52 , Henri Beauchamp wrote:

I don't see AT_TEXTURE listed: does it mean that we will still be able
to fetch textures via UDP sim messages ?
No, we plan to remove texture fetching via UDP at the same time (the 
person that drafted that note didn't realize we hadn't done that already 
and I didn't catch it).

My viewer has long been updated to make use of the newest HTTP fetching
capabilities, but it also implements an automatic fallback to UDP fetches
when HTTP ones fail (i.e. a texture failing to be served via HTTP is
automatically re-requested using UDP).
Better to requeue the request to HTTP after a suitable backoff (unless 
of course you get a error that indicates that a retry would not work).

Also, will AIS be made mandatory or will the non-AIS HTTP inventory
operations still be available ?  The reason for this question is that
AIS is still suffering failures from time to time, and the only solution
in that case is to disable it (or restart the sim)...
The effort to disable the UDP inventory operations is separate; we don't 
plan to make those changes until somewhat later. We'll post an 
announcement a few months out for that, but if there are UDP inventory 
operations you're using now that can be done through AIS, then you 
should be making those changes.


--
OZ LINDEN | Senior Director, Second Life Engineering
email or hangouts: o...@lindenlab.com  | Real 
Life: Scott Lawrence

LINDEN LAB | Create Virtual Experiences 
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Re: [opensource-dev] HTTP asset fetching will soon be mandatory

[Henri Beauchamp]

On Mon, 15 Oct 2018 15:27:12 -0400, Oz Linden (Scott Lawrence) wrote:

> In the interests of continuing to improve performance and user 
> experience, we will be removing the old non-HTTP fetching methods from 
> our simulators in early 2019. This means that any viewers that are still 
> fetching the affected asset types via UDP will no longer work correctly 
> after that time.
> 
> The affected asset types are:
>   * AT_LANDMARK
>   * AT_CLOTHING
>   * AT_BODYPART
>   * AT_GESTURE
>   * AT_ANIMATION
>   * AT_SOUND

I don't see AT_TEXTURE listed: does it mean that we will still be able
to fetch textures via UDP sim messages ?
My viewer has long been updated to make use of the newest HTTP fetching
capabilities, but it also implements an automatic fallback to UDP fetches
when HTTP ones fail (i.e. a texture failing to be served via HTTP is
automatically re-requested using UDP).

Also, will AIS be made mandatory or will the non-AIS HTTP inventory
operations still be available ?  The reason for this question is that
AIS is still suffering failures from time to time, and the only solution
in that case is to disable it (or restart the sim)...

Henri.
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[opensource-dev] HTTP asset fetching will soon be mandatory

[Oz Linden (Scott Lawrence)]

**

*For several years now, we have had the ability to fetch textures 
directly via HTTP. This has several advantages. It reduces load on the 
simulator, which no longer needs to act as an intermediary, and allows 
textures to be fetched reliably and efficiently using a CDN; this mean 
that data is more likely to come from a nearby machine, giving better 
performance for our residents. Last year, we added the ability to fetch 
several other types of in-world assets the same way, and have had very 
good results with the change. Although the Linden Lab official Second 
Life viewer no longer uses the old non-HTTP method of fetching assets, 
the simulator code has still been present, allowing other viewers to 
continue using the old method of fetching assets by way of the simulator.*


*

In the interests of continuing to improve performance and user 
experience, we will be removing the old non-HTTP fetching methods from 
our simulators in early 2019. This means that any viewers that are still 
fetching the affected asset types via UDP will no longer work correctly 
after that time.



The affected asset types are:

 *

   AT_LANDMARK

 *

   AT_CLOTHING

 *

   AT_BODYPART

 *

   AT_GESTURE

 *

   AT_ANIMATION

 *

   AT_SOUND


The planned date of the changeover is January 6, 2019. Please make sure 
any viewers you are working on have updated their asset fetching methods 
by then. If you have any questions about this process, please contact Oz.


*

--
OZ LINDEN | Senior Director, Second Life Engineering
email or hangouts: o...@lindenlab.com  | Real 
Life: Scott Lawrence

LINDEN LAB | Create Virtual Experiences 
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