Re: RMI Not Scalable?

Not sure if I get the relationship. 

-----Original Message-----
From: Oliver Chan [mailto:[email protected]] 
Sent: Tuesday, June 28, 2005 8:52 PM
To: [email protected]
Subject: Re: RMI Not Scalable?

Hi, I'd like to know if there's any difference in the use of internal
and external IP address of using firewall  Thanks!

On 6/26/05, Robert DiFalco <[email protected]> wrote:
> More and more I am finding RMI to not be a scalable solution for me. 
> For example, I have a system that could have upwards of 5000 hosts. 
> While there is only one server in the classic sense, the other nodes 
> have callbacks so they are also technically RMI servers and clients.
> 
> The communication between all these hosts and the "server" use a 
> pretty classic model to minimize concurrent socket usage on the 
> "server". There are async calls that just deposit runnable object into

> the server's thread queue and return and sync calls that do the same 
> thing but also register a listener in a local thread waiting for a 
> callback. In this way, for long sync tasks the socket only needs to be

> open long enough to deposit the runnable, and the "server" then 
> notifies the client who is blocking for response on a callback object.
> 
> 
> C sends task (including callback) to S 
>         -- the connection is done afterwards C waits in local thread 
> pool for the callback
>         -- requires no connection to S S completes task an sends 
> result to C using callback
>         -- a new connection just for the callback
> 
> 
> The problem is that even with a few hundred C hosts, the "server" can 
> get an incredible number of threads for RMI Connection, 
> ConnectionExpiration, and RenewClean.
> 
> So while I've designed my system to minimize the amount of long-lived 
> sockets (which is pretty important) I've created a new problem which 
> is a buttload of threads on the "server".
> 
> So my questions are this. 
> 
> 1. Should I just stop using RMI? I could always use my 
> RMISSLSocketFactory directly and use Marshaled objects directly -- 
> bypassing RMI completely.
> 
> 2. If I know that my C Remote Listener and "server" remote interfaces 
> are singleton instances that live as long as the application does, is 
> there a way to disable (or at least minimize) the creation of 
> RenewClean threads?
> 
> 3. Why is there a different thread for each ConnectionExpiration on 
> the "server"? I would think there would be just one thread for ALL 
> endpoints and I would only spawn a thread when I need to do something 
> (like expiration), otherwise there would be just one expiration
thread.
> 
> My guess is that RMI is wired so tightly that there is no way for me 
> to change the way #2 or #3 work, so that brings me back to #1.
> 
> R.
> 
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