[Opensim-dev] region status tracking in GridServer

[Brian Wolfe]

Unfortunately this is fatally flawed since teleports can fail due to
internet routing issues taht affect only one person, amongst other
movement failures that would cause the client to think a region is
offline vs the server knowing it's offline or online.

I'm posting a patch to mantis that lays the foundation for regions beign
online or offline and when they were last heard from by the grid server.



On Sat, 2008-02-09 at 21:25 +0100, Stefan Andersson wrote:
> Ok, I was to do some research before I replied on this thread, but off
> the top of my head;
>  
> first of all, we should define what we want the region status data
> for; the data should guide choice of implementation.
>  
> That said, there is quite a distinct possibility that we can use the
> _clients_ as our agents for detecting offline region servers.
>  
> Whenever someone tries to teleport off a region, the source region is
> informed of this, to be able to downgrade avatar presence to child.
>  
> If the teleport fails (the target region is unresponsive) the
> connection comes back to the region so it should upgrade the avatar
> presence to root again.
>  
> (Incidentally, I've filed a mantis on this, since we actually don't
> handle that, and failed teleports results in you coming back to a
> region, but as a 'child' ie being stuck there and possibly causing all
> kind of havoc with the ClientView)
>  
> Now, if we handled the failed teleport correctly, this could also
> notify the grid service that a failed teleport has occurred.
>  
> The grid service could then ping the target region, to check on its
> state.
>  
> This is an alternative or complement to grid-wide ping sweeps; you
> probably want both, but could do the sweeps much less frequently.
>  
> Combine this with proper region signon/signoff and I say you got
> options.
>  
> Best,
> /Stefan
> 
>  
> 
> ______________________________________________________________________
> 
> > From: brianw at terrabox.com
> > To: opensim-dev at lists.berlios.de
> > Date: Sat, 9 Feb 2008 12:56:10 -0600
> > Subject: [Opensim-dev] region status tracking in GridServer
> > 
> > After much IRC discussion I would like to make a couple changes to
> the
> > regions table.
> > 
> > online bool NOT NULL deafult false
> > last_seen int(11) NULL
> > 
> > The online column would be updated as a region logs in and out of
> > GridServers. This way an external management/status application
> doesn't
> > have to pester the grid server for the full list of regions and
> their
> > status. This would also provide data to regions requesting map
> blocks as
> > to the status of a region (a.ka. LL's Red Regions in the map view).
> > 
> > The last_seen column would be of asistance to these same management
> apps
> > in helping the administrator to determine which regions were long
> term
> > MIA or just plain not wanted anymore by walk away grid members.
> > 
> > My main concern is load placed on the grid server and having to ping
> > regions by external applications having to probe every region
> currently
> > to tell if it's still around or not.
> > 
> > To acomplish this i'm workign on a patch to implement region_logout
> > XMLRPC that would be called via
> Region.Communications.DeregisterRegion
> > (which is currently empty).
> > 
> > I woudl also add an update of RegionProfileData as each RPC call si
> made
> > by a region to GridManager. Database updates would only happen
> > periodicly as regions login and logout.
> > 
> > Are there any objections or reasons not to implement this?
> > 
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>