Re: [ws-rx] Minimalist GetMessage proposal

[Matthew Lovett <MLOVETT@uk.ibm.com>]

Hi Paul,

I've tried to answer your questions,
below:

Paul Fremantle <paul@wso2.com> wrote on 04/05/2006
16:13:28:

> Matt
> 
> I don't agree - perhaps not surprisingly. If the server closes the
> offered sequence, then there are three choices what to do.
> 
> 1) If there is a policy in place saying that the response should be
> reliable and there is no open sequence to the client then the server
> should fault back to the client and raise a fault locally.
> 2) If the response is not necessarily reliable (i.e. the policy or
> config allows either) and the response is ready, then the server should
> return the response unreliably. At this point the clients might spot
> this and GetMessage to the server and get back a fault.
> 3) If the response is not available then the server could return a
> terminate or close sequence to the client on the open backchannel.

Well, 1 and 2 sound like valid choices, but I'm a
bit confused by 3. Assuming this is a new request (not a replay), will
the message be dropped as well as returning the terminate/close, or will
it be sent for processing? I'd assume the latter is a bad idea, as we know
that the offered sequence is closed, so any reply is stuck. Perhaps the
logic of 1 and 2 comes back in here?

> 
> Perhaps you'd like to explain to me what would happen in this case
using 
> Doug's proposal because its not at all clear to me.
> 

Doug's case allows the server to establish new sequences
to the client as and when it chooses (modulo a transport connection giving
it a opportunity to send the create sequence message). That means that
there really is nothing special about the offered sequence, and if the
offered sequence is no longer the one that the server wishes to use then
it can set up another.

So, for the case I was discussing (where the server
side has needed to terminate the offered sequence and the client does not
know about the failure yet) I think we have no problems. The client can
send new requests and the server can go on and process them and the messages
can be transferred back to the client (who we can assume will come knocking,
as she isn't the one with the problem).

Did I manage to explain that clearly? Hope so!

Matt