Topics for the "Review input from TC members" session of the F2FSome

["Marin, Mike" <MMarin@filenet.com>]

I have few issues that I will like to add to the list of "Review input
from TC members" for the F2F meeting.

a- We don't have distributed transactions on web services yet.  So how
do we insure that an activity such as an "invoke" is executed exactly
one time?  The following example illustrates the problem:
 
1. Process A begins execution of an invoke instruction, and sends an
input message to Process B.  There is no output message defined on the
invoke.
2. Process B is defined with a receive instruction corresponding to the
invoke of process A, and the receive instruction creates a new instance
of the process.  So upon receipt of the message from process A, a new
instance of process B is created, and this instance executes the receive
instruction.
3. The machine hosting process A crashes.
4. Process B executes the next step, which is to debit an account and
update a database.
5. Process B terminates.  Process B has finished.
6. The machine hosting process A is restarted.  Process A then
re-executes the invoke instruction.  
 
On step 6, how can we prevent process A from executing the invoke a
second time, creating another instance of process B, and debiting the
account a second time?  

b- Invoking an operation, with input and output, that is implemented by
a process using receive and replay requires the WSDL operation to be
asynchronous. A process may take days or weeks between the receive and
the reply, so the client cannot keep a connection open waiting for the
reply. Although WSDL 1.1 talks about asynchronous operations; it does
not seems to be any support for it in the WSDL specification.