[I have put this back to the list. -- Thilo] On Fri, Jul 29, 2005 at 01:11:04PM +0200, Andre Merzky wrote:
As I see it, we have 2 different things:
1. session handles they are objects (data structures) within an application.
2. tasks they have some state stored at the job submission service/mechanism, at least while they are active and running
Andre's question is about associating a task to a session handle. IMHO, this should alway be possible (e.g., create a session handle and assign it a task).
To clearify that point: every task WILL be associated to a session handle. Always.
Question is, if that association can survive the lifetime/runtime of a application instance. And if that is necessary/wanted.
My guess would be that NO. There should be an OPTION (default) to associate a task with a session handle. You can see from your example that a mandatory/permanent association is not always possible.
An "interesting" problem might be to find back an old job within the job submission machanism. For this purpose, two options might be possible:
1. the application stores some task identifier "somewhere" 2. the job submission machanism allows to retrieve a list of all tasks, and the application (or an adaptor?) can match te right job based on the set of given properties...
3. the job submission machanism allows to retrieve a list of all tasks which the 'user' has access rights to, even if they have not been created by a SAGA application.
I am afraid though that we can mandate neither of these options: 1 needs persistent storage, which might not be available/accessible. 2 and 3 need support for task listing on server side, which is not always given AFAIK.
What should be mandated is an operation to associate a task to a session handle, based on some properties. The implementation (options 1, 2, 3, or even other) should go into the engine/adaptor implementation. In some cases, this association may just fail, tough luck if there is no implementation available under certain circumstances... Thilo -- Thilo Kielmann http://www.cs.vu.nl/~kielmann/