Re: optimizing link between client and server

[Simon Britnell <simon britnell peace com>]

Amitabh A. Nene wrote:

> I wanted to know how does one go about optimizing the link between a CORBA
> client and server using ORBit / any other ORB in general. In other words,
> how does one configure the link depending on whether the client and server
> are in the same address space, different address spaces on the same
> physical machine, or on separate physical machines ?

Hmmm.  I'm a little unsure of what you're asking.  Your question appears 
to be "How do I select which transport an ORB is using (SHM,TCP/IP,Unix 
Sockets,Sun RPC,etc) for any ORB?" The answer is "That depends on the 
ORB." ORBit specifically has a configuration file /etc/orbitrc which 
switches between unix sockets and tcp/ip as these are the transports it 
provides.".  Many ORBs automatically make the decision to use 
dync-call/no marshalling whenever they detect that they are both the 
client and the server for an IOR.  I *think* ORBit is one of these.

It also occurs to me that your real issue may be a performance one, in 
which case I can only say "Minimise round trips".  The further the 
distance between your client and server, the bigger the latency penalty 
you will pay.  Calling a remote object method fetchNextFoo() repeatedly 
to fetch a thousand records will perform fine over SHM where latency is 
<1ms, but will die screaming over the internet even at a latency of only 
100ms (giving a 10 second response time for 1000 records in latency 
alone) and >500ms latencies are not uncommon.  Far better to implement a 
method fetchAllFoo() which is called once.

> Also, in the current ORBit implementation, do these paths translate to
> dyn-call/no-marshaling, shared-mem, and RPC respectively, if at all ?

I don't think ORBit does SHM yet.  I know it does dyn-call, unix 
sockets, tcp/ip4 and tcp/ip6 (same ram address space, same machine, 
seperated by network).

Hope this helps.