[mapguide-internals] How can MapGuide support more than 64 connections on Windows ?

Sat Mar 14 17:36:00 EDT 2009

Has anyone tried turning on connection pooling for SDF?  Does it help?

-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org
[mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Zac =
Spitzer
Sent: Wednesday, March 11, 2009 8:00 PM
To: MapGuide Internals Mail List
Subject: Re: [mapguide-internals] How can MapGuide support more than 64
connections on Windows ?

yep I see this kind of thing all the time too....

what is especially annoying is the fact that the process locks up and
can often only be killed by a reboot or using something like zerowave...

it's mapguide really should respond promptly to a service stop request

http://trac.osgeo.org/mapguide/ticket/722
http://trac.osgeo.org/mapguide/ticket/775

but i think the problems are most likely interlinked :)

z

2009/3/7 Jason Birch <Jason.Birch at nanaimo.ca>:
> I think I may be running into this problem when real-life-testing my
application too.
>
> I have five users, each running 2-3 browser sessions and just
panning/zooming.  After about 15 minutes of this, we started getting
connections refused; first on Fusion calls to things like the legend PHP
code, and then on image calls, and eventually no calls were succeeding.
>
> I don't know if it's related to this or not:
>
> http://trac.osgeo.org/mapguide/ticket/726
>
> Jason
>
> -----Original Message-----
> From: mapguide-internals-bounces at lists.osgeo.org
[mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of sftp
> Sent: February-22-09 9:44 PM
> To: MapGuide Internals Mail List
> Subject: =BB=D8=B8=B4:RE: [mapguide-internals] How can MapGuide =
support more than
64 connections on Windows ?
>
> Trevor Wekel,
> Thank you very much!
> Several days ago, I just wanted to know how the MapGuide server =
controls
the number of connections for Client,Admin,Site separately.
> And i found no logic in the source code to limit the max connections =
for
the services. So i read the source code of ClientAcceptor,ClientHandler =
and
found ACE_Reactor and ACE_WFMO_Reactor ,then my original question came =
up.
>
> Yesterday, i reread the source code and found the MgServerConnection
implementation and found the sockets pool.
>
> But i still have two question:
> 1. How did the MapGuide server control the max connections of each =
kind of
service (client,admin,site)?
> 2. Imagine a extreme senario: If there are several WebTier process in =
the
same/different machines, and they all have their own socket pool, if the =
sum
of sockets are more than 64, the clientAcceptor can accept the =
connections,
but the socket read/write operations will fail because the dispatcher =
can
not dispatch more than 64 connections. Am i right?
>
>
>
>>I have not looked deeply into the interaction between the =
MgClientAcceptor
>>class and the ACE::reactor.  It is possible that there may be a =
limitation
>>on the number of connections to the server.  From what I remember,
>>MgClientAcceptor creates new connections and MgClientHandler handles =
the
>>processing for these connections.  Each MgClientHandler operates on a
>>separate thread.
>>
>>>From an architectural perspective, I do not believe this will be a
>>performance problem.  The communications channel between the server =
and
web
>>tier has been designed to pool and reuse the TCP/IP connections =
between
the
>>two processes.  This means a TCP/IP connection is only active when =
there
is
>>an actual service request (MgRenderingService, MgMappingService, etc)
being
>>performed.  Once the request is completed, the connection is freed up =
to
be
>>used by another client.
>>
>>This means even with a limitation of 64 connections, the MapGuide =
Server
>>would be simultaneously processing work on 64 separate threads.  Since =
no
>>manufacturer currently makes a machine with more than 24 cores, a 64
>>connections/threads limit would still keep the MapGuide Server very =
busy.
>>
>>Are you trying to solve an issue related to
>>http://trac.osgeo.org/mapguide/ticket/726?
>>
>>I did a quick check on the implementation of the web tier's connection
logic
>>(MgServerConnection, MgServerConnectionStack, etc).  Even though we =
reuse
>>connections, it looks as though we do not set a hard limit on the =
number
of
>>connections a web tier will make to the server.  A large number of =
users
>>running very slow operations could force the web tier to create more
>>connections than the server can handle.
>>
>>We could add an additional parameter to webconfig.ini which puts a =
hard
>>limit on the number of connections the web tier will create.  The only
>>problem with this approach is that the limit will be per process and =
apply
>>to both the mapagent and any implementation of the web extensions =
(PHP,
>>.Net, Java).  This will get a bit tricky when web servers like IIS =
spin up
>>multiple instances of these processes.
>>
>>Thanks,
>>Trevor
>>
>>
>>-----Original Message-----
>>From: mapguide-internals-bounces at lists.osgeo.org
>>[mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of sftp
>>Sent: Sunday, February 22, 2009 12:46 AM
>>To: mapguide-internals at lists.osgeo.org
>>Subject: [mapguide-internals] How can MapGuide support more than 64
>>connections on Windows ?
>>
>>
>>I have read the source code and i found that it used ACE::reactor =
default
>>implementation ACE_WFMO_Reactor on Windows.
>>ACE_WFMO_Reactor can only handle no more than 64 handles in one =
thread, so
>>how can
>>MapGuide support more than 64 socket connections?
>>
>>Maybe I didn't understand the source code.
>>Can anybody help me out?
>>--
>>View this message in context:
>>http://n2.nabble.com/How-can-MapGuide-support-more-than-64-connections-=
on-
Wi
>>ndows---tp2366663p2366663.html
>>Sent from the MapGuide Internals mailing list archive at Nabble.com.
>>
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--=20
Zac Spitzer -
http://zacster.blogspot.com
+61 405 847 168
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