=?gbk?Q?=BB=D8=B8=B4:RE:_[mapguide-internals]_How_can_MapGuide_?= =?gbk?Q?support_more_than=0964=09connections_on_Windows_=3F?=

[sftp]

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:
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>ndows---tp2366663p2366663.html
>Sent from the MapGuide Internals mailing list archive at Nabble.com.
>
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