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Subject: RE: [wsrp] [wsia] [wsrp-wsia joint interfaces] agenda for Tuesday 11June
My comments are embedded in [CL] tags.
Best regards
Carsten Leue
-------
Dr. Carsten Leue
Dept.8288, IBM Laboratory Böblingen , Germany
Tel.: +49-7031-16-4603, Fax: +49-7031-16-4401
|---------+----------------------------->
| | Eilon Reshef |
| | <eilon.reshef@webc|
| | ollage.com> |
| | |
| | 06/11/2002 09:37 |
| | PM |
| | Please respond to |
| | Eilon Reshef |
| | |
|---------+----------------------------->
>---------------------------------------------------------------------------------------------------------------------------------------------|
| |
| To: "'Alan Kropp'" <akropp@epicentric.com>, wsia@lists.oasis-open.org, wsrp@lists.oasis-open.org |
| cc: |
| Subject: RE: [wsrp] [wsia] [wsrp-wsia joint interfaces] agenda for Tuesday 11 June |
| |
| |
>---------------------------------------------------------------------------------------------------------------------------------------------|
Alan,
Comments below, with <ER>
I'll follow up with a related question in a subsequent e-mail
Eilon
-----Original Message-----
From: Alan Kropp [mailto:akropp@epicentric.com]
Sent: Tuesday, June 11, 2002 3:05 PM
To: 'Eilon Reshef'; Alan Kropp; wsia@lists.oasis-open.org;
wsrp@lists.oasis-open.org
Subject: RE: [wsrp] [wsia] [wsrp-wsia joint interfaces] agenda for Tuesday
11 June
Hi Eilon,
It seems to me the Consumer still doesn't really need a say in how
the Producer implements the search service runtime model. It's true
that if the Producer creates all of these transient entities, there
is the issue of when it is "safe" to destroy them. Transient
entities don't have an inherent lifecycle, but the sessions which
talk to them do...so, when these sessions have timed out, the
Producer is able to determine that a transient entity is no longer a
party to any active session. Would it be valid to say that the
Producer, at that point, may assume the transient entity is stale and
destroy it?
<ER> I would think so </ER>
[CL] I would agree as well, only that it is not the producer but the
consumer that creates the transient entities. [CL]
I guess this is a variation on reference counting/GC that Java
developers are already familiar with.
<ER> yes, except that reference counting is possible in a closed
environment, whereas "guesswork" (i.e., timeouts ;-) is the option
that will be used in practice </ER>
[CL] Garbage collection cannot really be done cleanly in such a
distributed environment. Java's "Mark & Sweep" only works if the
system knows all objects (not the case for WSRP) and reference
counting suffers from possible cycle generation. I assume that the
concept of timeouts for transient entities will work best here (maybe
combined with reference counting to give hints on the lifetime, but
that's an implementation detail). [CL]
I don't think it's unrealistic to expect the Producer to employ
intelligence like this to efficiently manage its entities.
<ER> I would assume that transient entities would be implemented as
or within sessions, as you suggested so this would be taken care by
the infrastructure </ER>
Alan
-----Original Message-----
From: Eilon Reshef [mailto:eilon.reshef@webcollage.com]
Sent: Tuesday, June 11, 2002 11:36 AM
To: 'Alan Kropp'; wsia@lists.oasis-open.org;
wsrp@lists.oasis-open.org
Subject: RE: [wsrp] [wsia] [wsrp-wsia joint interfaces] agenda
for Tuesday 11 June
Alan,
I think that one example scenario is a search results page, say
for hotels, that dynamically displays multiple maps - a map for
each hotel found.
Assuming that maps are remote services, and assuming that the
number of results is dynamic, the Consumer needs to create
multiple copies of the map service. If we allow the Producer to
determine the persistence state of those maps, that would mean
that someone will have to take care of the lifetime of those
maps. The Consumer can't, because the page may be gone without
the Consumer never knowing about it (the user closes the
browser window). The Producer can't, because it can't tell
whether the Consumer has stored a reference to those maps as
part of a design-time description of a user page.
Is that along the lines of what you were looking for?
Eilon
-----Original Message-----
From: Alan Kropp [mailto:akropp@epicentric.com]
Sent: Tuesday, June 11, 2002 2:18 PM
To: 'wsia@lists.oasis-open.org';
'wsrp@lists.oasis-open.org'
Subject: RE: [wsrp] [wsia] [wsrp-wsia joint interfaces]
agenda for Tuesday 11 June
I find that the question of a Consumer creating a
persistent vs. a transient
entity to be a little troubling.
Isn't the Consumer primarily interested in getting a
handle to an _entity_
(be that transient or persistent), and then using that
handle to direct
subsequent requests to?
Could we not consider persistence and transience to be
entirely Producer
concerns? I understand from the sequence in the spec
(pp. 6-8) that the
only supporting scenario for the Consumer calling
"createTransientEntity" is
out of an effort to maximize the efficiency of the
conversation with the
Producer. This is a worthy goal, of course, but the
Producer should
advertise its interaction behavior in the meta-data,
right? Presumably the
Producer uses the meta-data to hint to the Consumer the
way(s) the Consumer
SHOULD structure invocation requests efficiently.
I'd love to see some more convincing scenarios to support
pushing the
persistent/transient aspect of the conversation out to
the Consumer.
Otherwise, I'd love even more to limit our specification
to a single
"createEntity" call.
Alan
-----Original Message-----
From: Carsten Leue [mailto:CLEUE@de.ibm.com]
Sent: Tuesday, June 11, 2002 2:19 AM
To: Gil Tayar
Cc: thomas klein6; 'wsia@lists.oasis-open.org';
'wsrp@lists.oasis-open.org'
Subject: RE: [wsrp] [wsia] [wsrp-wsia joint interfaces]
agenda for
Tuesday 11 June
Gil -
1-3: the consumer MUST explicitly create entities
(transient or
persistent). It can decide to create sessions explicitly
if it wants to
share them amongs entities, otherwise it can let the
producer create
sessions on the fly.
4: the decision to have multiple entities per session is
up to the consumer
who make this choice based on the producer's metadata.
e.g think of
portlets that form a shop together. These would want to
share a session
with each other. But the consumer could decide to have
two shops of the
same type on the same page. Then there would be two
sessions and only the
consumer could know what portlet shares what session.
5: The consumer should create a session before issuing a
getFragment call.
The entity is created whenever necessary.
6: A Session is a bucket that holds some data (physically
on the provider)
and times-out after a while. A transient entity is a
remote portlet that
does not store any data in a DB.
Hope that helped.
Best regards
Carsten Leue
-------
Dr. Carsten Leue
Dept.8288, IBM Laboratory Böblingen , Germany
Tel.: +49-7031-16-4603, Fax: +49-7031-16-4401
|---------+---------------------------->
| | Gil Tayar |
| | <Gil.Tayar@webcol|
| | lage.com> |
| | |
| | 06/11/2002 09:28 |
| | AM |
| | Please respond to|
| | Gil Tayar |
| | |
|---------+---------------------------->
>
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|
| To: Carsten Leue/Germany/IBM@IBMDE
|
| cc: "'wsia@lists.oasis-open.org'"
<wsia@lists.oasis-open.org>,
"'wsrp@lists.oasis-open.org'"
<wsrp@lists.oasis-open.org>, Thomas|
| Klein6/Germany/IBM@IBMDE
|
| Subject: RE: [wsrp] [wsia] [wsrp-wsia joint
interfaces] agenda
for Tuesday 11 June
|
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>
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Carsten, could you clarify some things for me?
1. If sessions and entities are orthogonal, what SHOULD
the Consumer do?
2. SHOULD it create a transient entity _and_ a session?
3. MUST it do so?
4. Who gets to decide whether there are multiple entities
per session or
multiple sessions per entities?
5. When SHOULD a Consumer create a session and when a
transient entity?
6. What _is_ a session, logically? What _is_ a transient
entity?
Gil
-----Original Message-----
From: Carsten Leue [mailto:CLEUE@de.ibm.com]
Sent: Tuesday, June 11, 2002 08:45
To: Alan Kropp
Cc: 'wsia@lists.oasis-open.org';
'wsrp@lists.oasis-open.org'; thomas
klein6
Subject: Re: [wsrp] [wsia] [wsrp-wsia joint interfaces]
agenda for
Tuesday 11 June
Alan - some first thoughts
1. the general concept is that entities (transient or
persistent) and
sessions are orthogonal. There might be mulitple entities
per session and
(at least for persistent entities) multiple sessions per
entity. An example
for the first case would be that entities share session
data within the
same user request. An example for the second case are
portlets on a common
page (group page) that are access simultaneously by
multiple users.
A transient entity differs from a persistent entity in
that its data does
not persist and its lifecycle is coupled with the session
life cycle.
2. Eilon pointed out in a comment to the interface
proposal that batch
processing is already part of SOAP. I was not aware of
that and will look
it up until the call.
Best regards
Carsten Leue
-------
Dr. Carsten Leue
Dept.8288, IBM Laboratory Böblingen , Germany
Tel.: +49-7031-16-4603, Fax: +49-7031-16-4401
|---------+---------------------------->
| | Alan Kropp |
| | <akropp@epicentri|
| | c.com> |
| | |
| | 06/11/2002 01:54 |
| | AM |
| | Please respond to|
| | Alan Kropp |
| | |
|---------+---------------------------->
>
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|
|
| To: "'wsrp@lists.oasis-open.org'"
<wsrp@lists.oasis-open.org>,
"'wsia@lists.oasis-open.org'"
<wsia@lists.oasis-open.org> |
| cc:
|
| Subject: [wsrp] [wsia] [wsrp-wsia joint
interfaces] agenda for
Tuesday 11 June
|
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I think we'll have plenty of discussion around the merged
document Rich and
Carsten put together.
The two main issues I see that have arisen on the email
lists are:
1. What is the difference between transient entities and
sessions, and is
there enough of a distinction to warrant including both
in the
specification?
2. There are efficiency concerns around the use of
arrays in the method
signatures, basically to enable batched requests for
network efficiency.
Call-in numbers:
USA Toll Free Number: 877-718-0936
USA Toll Number: +1-712-923-6878
PARTICIPANT PASSCODE: 563151
Alan
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