[omniORB] Marshall exception -- message size limit exceeded

[Philippe Selo]

Luke,

thanks for the clarification, I missed Duncan's point about the two
buffer limits.

p.

On 2/5/07, Luke Deller <ldeller at xplantechnology.com> wrote:
> Philippe wrote:
> > Maybe I'm missing something.
> ...
> > Of course we can raise the max size limit on the client and
> > server but if the response is arbitrary large, there is
> > always a chance of exceeding the limit, so I think it can
> > be helpful for the client to "know" that it will never get
> > the answer, even if it retry.
>
> I understand that you want the client to know why the request failed
> when a message size limit is exceeded.  I'm saying that this can be
> achieved if the message size limit is exceeded in the right place: in
> the client as it receives the response, rather than in the server as it
> sends the response.
>
> Let me try to explain what I mean with two examples.
>
> Example 1:
> - giopMaxMsgSize is set to 4MB in server and client processes
> - your function tries to return a 50Mb result
>
> In this example, the server process will start sending the response to
> the client.  When the server realises that the response is >4Mb, it will
> abort sending the response, triggering a COMM_FAILURE.  Unfortunately as
> we have discussed there is no way for the server to raise a more useful
> exception at this stage because it has already started sending a
> response.  This outcome is not what you want.
>
> Example 2:
> - giopMaxRecvMsgSize is set to 4Mb in server and client processes
> - giopMaxSendMsgSize is set to 32Mb in server and client processes
> - your function tries to return a 50Mb result
>
> Again, the server process will start sending the response to the client.
> The server will happily keep sending past 4Mb of data, but when the
> client realises that the response it is receiving is >4Mb it will abort
> receiving the response, and raise a MARSHAL exception with a descriptive
> minor code.  This is the outcome that you want.
>
> The second example only works if somebody implements giopMaxRecvMsgSize
> and giopMaxRecvMsgSize settings in omniORB.
>
> Regards,
> Luke.
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