[omniORB] Single-threaded behaviour changed between omniORB3 & omniORB4?

[Donnacha Forde]

> 
> It sound like an assumption of 1 connection per
> client is made in the
> discussion below.  That may be the case for some
> client ORBs (notably I've
> seen this with some Java ORBs).  But I understand
> that omniORB itself, when
> used as a client will open additional connections
> from a multithreaded
> client that is doing concurrent calls on the same
> server, even if those
> calls are on the same object.  That should apply to
> v3 and v4 of omniORB.
> In general, don't make assumptions about the
> concurrency or lack thereof
> that the clients may trigger.  The server needs to
> enable policies that
> guarantee proper synchronization.  In some cases a
> single thread POA is the
> right thing, in other cases a servant and the
> application code should have
> it's own synchronization logic to protect critical
> areas.

Yes, you're absolutely right here. 


> 
> Perhaps if Donnacha can explain exactly what sort of
> concurrency needs to
> be prevented, the group here can help.  It doesn't
> sound to me like
> modifying configuration options is the right
> solution.  I think a minor
> redesign of the app is in order.
> 

Yes. The point is that while configuration options may
reduce the likelihood of unwanted concurrency, they
will not eliminate it. Ultimately, as you explain
above, this has to be controlled in the server. 

WRT my issue, I believe if I establish a
SINGLE_THREAD_MODEL policy in my server, then I’ll be
fine. I’m currently hunting down a code example. 

You see, this server was initially written using Orbix
3.x (i.e. BOA), which has single-threaded servers by
default. It was then ported to Orbix 2000 2.0 (i.e.
POA) and then omniORB3.x. and now has been rebuilt
with omniORB-4.x. As part of this journey, I missed
the fact that POA does not have single-threaded
behaviour by default. 

Regards,
Donnacha



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