Regarding the groups work, I have now implemented an OpenSimulator experimental option, MessageOnlineUsersOnly in
[Groups] as of git master 1937e5f. When set to true this will only send group IMs to online users. This does not
require a groups service update. I believe OSGrid is going to test this more extensively soon though it appears to work
fine on Wright Plaza.
It's temporarily a little spammy on the console right now (what isn't!) with a debug message that says how many online
users it is sending to and how long a send takes.
Unlike Michelle's solution, this works by querying the Presence service for online users, though it also caches this
data to avoid hitting the presence service too hard.
Even though I implemented this, I'm not convinced that it's the best way to go - I think Michelle's approach of sending
login/logoff status directly from simulator to groups service could still be better. My chief concern with the groups
approach is the potential inconsistency between online status stored there and in the Presence service. However, this
could be a non-issue. Need to give it more thought.
On 14/10/12 22:53, Akira Sonoda wrote:
IMHO finding out which group members are online and sending group IM/Notice
etc. to them actually should not be done by
the region server from which the group IM/notice etc. is sent.
This is a task which should be done centrally in case of OSgrid in Dallas TX (
http://wiki.osgrid.org/index.php/Infrastructure ). The region server should
only collect the group IM/notice etc. and
send it to the central group server or in the other way receiving IM/notice
etc. from the central group server and
distribute it to the Agents active on the region(s).
That concentrates all distribution on a central point rather than spreading it amongst simulators. Then OSGrid has the
problem of scaling this up.
Having said that, there are advantages to funnelling things through a reliable central point. As to which is better is
a complicated engineering issue - the kind of which there are many in the MMO/VW space.
But there are even other places which can and should be improved. I did some
tests with some viewers counting the web
requests to the central infrastructure:
Test 1: Teleport from a Plaza to one of my regions located on a server in
Europe and afterwards logging out:
Cool VL Viewer: 912 Requests mostly SynchronousRestForms POST
http://presence.osgrid.org/presence ( i guess to inform
all my 809 friends [mostly only 5% online] I am going offline because the calls
to the presence service were done after
i closed the viewer)
Singularity Veiwer: 921 Requests mostly calls to presence after logoff
Teapot viewer: 910 Requests mostly calls to presence after logoff
Astra Viewer: 917 Requests mostly calls to presence after logoff
Firestorm: 1005 Requests mostly calls to presence after logoff
Imprudence: 918 mostly calls to presence after logoff
So far so good. I have no idea why my 760 offline friends have to be informed
that I went offline ...
(Details can be found here:
https://docs.google.com/open?id=0B301xueh1kxdNG1wLWo2YVVfYjA )
Test 2: Direct Login onto my Region and then Logoff-( with FetchInventory2
disabled )
Cool VL Viewer: 2232 Requests mostly calls to presence ~800 during login and
~800 during logout and xinventory
Singularity Viwer: 2340 Requests mostly calls to presence and xinventory
Teapot Viewer: Produced 500+ Threads in a very short time and then the
OpenSim.exe crashed
Astra Viewer: 2831 Request mostly calls to presence and xinventory
Firestorm Viwer: ACK Timeout for me. OpenSim.exe survived on 500 Threads for
30+ minutes producing 4996 Requests mostly
xinventory
Imprudence: 1745 Requests mostly presence
Again why do all my 809 friends have do be verified with single requests? Then
why this difference in xinventory
Requests? And why are both Teapot and Firestorm producing so many Threads in
such a short time? and bring OpenSim.exe to
crash or closely to crash ...
( Details can be found here:
https://docs.google.com/open?id=0B301xueh1kxdMDJxWm5UR2QtU2c )
The presence information is useful data and it was possible in git master commit da2b23f to change the Friends module to
fetch all presence data in one call for status notification when a user goes on/offline, rather than make a separate
call for each friend.
This should be more efficient since only the latency and resources of one call is required. However, since each friend
still has to be messaged separately to tell them of the status change I'm not sure how much practical effect this will have.
Test 3: Direct Login to my Region with FetchInventory2 enabled.
Teapot Viewer: I closed the viwer after 30 minutes. Number of Threads were
still rising up to 260. In the end i counted
30634 xinventory requests... My Inventory has 14190 items !!!
Firestorm Viwer: Quite normal approx 2020 Requests ... quite some slow
FetchInventoryDescendandts2 Caps. with 100 sec max
Regarding inventory service, unfortunately many viewers appear to behave very aggressively when fetching inventory
information. For instance, I'm told that if you have certain types of AO enabled - some viewers will fetch your entire
inventory. The LL infrastructure may be able to cope with this but the more modest machines running grids can have
trouble, it seems.
I'm not sure what the long term solution is. I suspect it's possible to greatly increase inventory fetch efficiency,
possibly by some kind of call batching. Or perhaps there's some viewer-side caching that OpenSimulator isn't working
with properly.
( Details can be found here:
https://docs.google.com/open?id=0B301xueh1kxdNEtEeUVFamU1QUE )
Just my observations this week end.
Akira
2012/10/13 Justin Clark-Casey <[email protected]
<mailto:[email protected]>>
Hi Michelle. I've now had some more time to think about this. In fact, I
established a proposal summary page at
[1] which I'll change as we go along (or please feel free to change
yourself). We do need to fix this problem of
group IM taking massive time with groups that aren't that big.
I do like the approach of caching online status (and login time) in the
groups service.
1. It's reasonably simple.
2. One network call to fetch online group members per IM.
3. May allow messaging across multiple OpenSimulator installations.
However, this approach does mean
1. Independently updating the groups services on each login/logout. I'm
not saying this is a problem, particularly
if it saves traffic later on.
2. Groups service has to deal with extra information. Again, this is
fairly simple so not necessarily a fatal
issue though it does mean every groups implementations needs to do this in
some manner.
3. Online cache is not reusable by other services in the future.
On a technical note, the XmlRpc groups module does in theory cache data for
30 seconds by default, so a change in
online status may not be seen for upto 30 seconds. I personally think that
this is a reasonable tradeoff.
Rather, of the above cons, 3 is the one I'm finding most serious. If other
services would also benefit from online
status caching in the future, they would have to implement their own caches
(and be updated from simulators).
I do agree that making a GridUser.LoggedIn() call for every single group
member on every single IM is unworkable.
Even if this is only done once and cached for a certain period of time it
could be a major issue for large groups.
So an alternative approach could be to add a new call to GridUser service (maybe
LoggedIn(List<UUID>) that will only
return GridInfo for those that are logged in. This could then be cached
simulator-side for a certain period of time
(e.g. 30 seconds like the groups information) and used for group IM.
This has the advantages that
1. Groups and future services don't need to do their own login caching.
2. Future services can use the same information and code rather than have
to cache login information themselves.
However, it does
1. Require GridUserInfo caching simulator-side, I would judge this to be a
more complex approach.
2. Mean that during the cache period, new online group messages will not
receive messages. (this is going to
happen with GetGroupMembers() caching anyway).
3. Traffic is still generated to the GridUser service at the end of every
simulator-side caching period. This is
probably not a huge burden.
So right now, I'm somewhat more in favour of a GridUserInfo simulator-side
caching approach than caching login
information within the groups service. However, unlike you, I haven't
actually tried to implement this approach so
there may well be issues that I haven't seen.
What do you think, Michelle (or anybody else)?
On 10/10/12 19:47, Michelle Argus wrote:
http://code.google.com/p/__flotsam/ <http://code.google.com/p/flotsam/>
is the the current flotsam version and
points to the github repro which I forked and
then patched.
None of the changes I proposed in my git fork have been implemented,
neither in opensim nor in flotsam.
Consider my proposal as a quick fix for the time beeing which does
not solve all other issues mentioned by later
mailings.
Am 09.10.2012 10:24, schrieb Ai Austin:
Michelle Argus on Wed Oct 3 18:00:23 CEST 2012:
I have added some changes to the group module of OpenSim and
the flotsam server.
...
The changes can be found in the 2 gits here:
<https://github.com/MAReantals__>https://github.com/MAReantals
NB: Both changes to flotsam and opensim are backward compatible
and do
not require that both parts are updated. If some simulators are
not
updated it can happen that some groupmembers do not receive
groupmessages as their online status is not updated correctly.
In a grid
like OSgrid my recomendation would thus be to first update the
simulators and at a later stage flotsam.
Hi Michelle... I am looking at what is needed to update the Openvue
grid which is using the flotsam XmlRpcGroups
module. the GITHub repository has the changes from a few days
ago... but I wonder if there has been an
update/commit
into the main Opensim Github area already. I cannot see a related
commit looking back over the last week
or so. Is
the core system updated so this module is up to date in that? I
also note that the Opensim.ini.example file
contains
a reference to http://code.google.com/p/__flotsam/
<http://code.google.com/p/flotsam/> for details of how to
install the service.. but that seems to be
pointing at an out of date version?
I think for the flotsam php end it is straightforward and I
obtained the changed groups.sql and xmlrpc.php files
needed. But note that people are still pointed via the
opensim.ini.example comments at the old version on
http://code.google.com/p/__flotsam/
<http://code.google.com/p/flotsam/> so that either needs updating to teh
latest version, or the comment in
opensim.ini.exmaple needs to be changed.
To avoid mistakes, I wonder if you can clarify where to go for the
parts needed and at what revision/date of
OpenSim
0.7.5 dev master this was introduced, what to get and what to
change for an existing service in terms of the
data base
tables, OpenSim.exe instance and the web support php code areas?
Thanks Michelle, Ai
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