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Subject: RE: [wsdm] Groups - OperationMetricsProposal (MowsOpMetrics.doc) uploaded
- From: David E Cox <decox@us.ibm.com>
- To: wsdm@lists.oasis-open.org
- Date: Mon, 24 Oct 2005 16:15:31 -0400
I do not agree that Start and Stop don't
make sense on an operation by operation basis. In most app servers,
Start and Stop aren't going to be directly implementable at the service
level. Web services in j2ee containers (for example) are probably
stateless session beans that are not "running" but are rather
driven when a request comes in. Therefore Start and Stop are probably
implemented not by stopping some long-running process (because there is
none), but rather by blocking the messages. Therefore it is perfectly
possible and reasonable to allow blocking messages at the operation granularity.
Similarly, as my examples below illustrated,
a Web service is not a monolithic resource. There can and will be
cases where one operation is available and another is not. One operation
may have a dependency is that is unavailable, and other operations may
not have that dependency. In that case, you can state that the entire
Web service is unavailable, which is incorrect because maybe every operation
except one is available. Otherwise, you state that if any operation
is Available, then the Web service is Available. In that case, you
may have Service Level Agreements that are failing due to a particular
operation not working, because your management tool doesn't have granular
visibility to the state of the operations. You may even have the
case where some operations are processed in a completely different container
than other operations (probably on a port-type boundary).
Another example is that one business
process might use one operation on a service, and a different business
process might use another operation on the same service. Without
status granularity to the operation, in the case where one operation is
unavailable and the other is available, the management tool will have to
conclude that both business processes are impacted or not without being
able to tell that one is impacted and the other is not.
In summary, I think that start,
stop, state, status, and relationships do have meaning for operations within
a Web service. I also believe that providing this level of manageability
will be critical to actually isolating and diagnosing problems in Web services.
Regards,
David E Cox
"Murray, Bryan P."
<bryan.murray@hp.com>
10/24/2005 03:58 PM
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To
| David E Cox/Raleigh/IBM@IBMUS,
<wsdm@lists.oasis-open.org>
|
cc
|
|
Subject
| RE: [wsdm] Groups - OperationMetricsProposal
(MowsOpMetrics.doc) uploaded |
|
I do not know what it means to
have a Start resource, or a Stop or Reset resource. To me, operations are
the actions that can be done to a resource, not resources in themselves.
I do not know of other models that define resources for the actions to
be taken on a resource - CIM does not.
To get back to the original subject,
I agree with Kirk about State and Status not really making sense on a per
operation basis. A resource is in a particular state. Some operations are
designed to change that state. Sometimes the state changes for some resource-specific
reason. I don't see State as inherently being different just because a
certain operation is being processed (except for those operations designed
to change a state).
We are defining metrics on a per
operation basis, not because metrics are inherently different for different
operations, but to report more detailed data than the resource-wide metrics
are able to do. The resource-wide metric incorporates all of the data that
the individual per operation metrics do as a summary, but sometimes a management
application wants to have more detailed information about some critical
operation than is available with the original set of metrics.
Bryan
From: David E Cox [mailto:decox@us.ibm.com]
Sent: Monday, October 24, 2005 12:38 PM
To: wsdm@lists.oasis-open.org
Subject: RE: [wsdm] Groups - OperationMetricsProposal (MowsOpMetrics.doc)
uploaded
Hi Kirk,
I agree that if the service is Unavailable, quite likely all of
the operations are unavailable. The reverse, however, may not be
true. The operations in a service may vary widely in what they require
in order to accomplish their function. For example, reading a record
may work whereas writing a record may not (due to locking issues, etc).
Another example is that some operations may be simple, self-contained
operations that always work, but other operations may call out to other
web services or non-web services dependencies (such as a database) that
may or may not be up. Operations that access one table in a databsae
that has performance problems or poor tuning may show a degraded or unacceptable
response time, while other operations work fine.
From that perspective, I would have to get out a great big can opener
and open a can of worms. Just about (but not quite) everything in
the MOWS spec can be different from one operation to the next within a
web service. The metrics, state, and status, plus the relationships
can certainly be different. Message processing state can be different.
Would it make sense to model operations as resources, rather than
trying to qualify most but not everything in MOWS with operation qualifiers?
This would be in addition to the model of a Web service as a whole,
not a replacement for it. Let's discuss first whether it might or
might not make sense academically, before we reject it out of hand because
it seems "hard" or too much trouble.
Regards,
David E Cox
"Wilson, Kirk D"
<Kirk.Wilson@ca.com>
10/24/2005 03:02 PM
|
To
| David E Cox/Raleigh/IBM@IBMUS,
<fred.carter@amberpoint.com>
|
cc
| <wsdm@lists.oasis-open.org>
|
Subject
| RE: [wsdm] Groups - OperationMetricsProposal
(MowsOpMetrics.doc) uploaded |
|
On second thought: I’m not sure what value per-operation status
and state will have. If the service is Available or Unavailable,
that would apply generally to the operations within the service. Perhaps
if the service is Partially Aavailable we might what to drill down to see
what operations are available or not—does anyone have any opinions on
this?? I believe that state model used for operational state is pretty
much defined for the service-level state.
On the other hand, I think we should include the operationName/portTypeName
attributes that are part of the OperationMetric capability as part of the
RequestProcessingStateType so that notification consumer can know what
process is being talked about. (I assume what is meant by “operation”
in the OperationMetric is the same thing that is being talked about as
a “request” in the RequestProcessingState. If so, then we should
probably use of consistent vocabulary and talk about a RequestMetric and
Request metric properties. Opinions on this??)
Kirk Wilson
Architect, Development
Office of the CTO
802 765-4337
-----Original Message-----
From: Wilson, Kirk D
Sent: Friday, October 21, 2005 4:59 PM
To: 'David E Cox'; fred.carter@amberpoint.com
Cc: wsdm@lists.oasis-open.org
Subject: RE: [wsdm] Groups - OperationMetricsProposal (MowsOpMetrics.doc)
uploaded
Dave, yes I agree. I already brought up about an operation processing
state (and, correspondingly) notifications. I think the general consensus
was that it would be more difficult. I agree that this issue should
be revisited.
Kirk Wilson
Architect, Development
Office of the CTO
802 765-4337
-----Original Message-----
From: David E Cox [mailto:decox@us.ibm.com]
Sent: Friday, October 21, 2005 8:05 AM
To: fred.carter@amberpoint.com
Cc: wsdm@lists.oasis-open.org
Subject: Re: [wsdm] Groups - OperationMetricsProposal (MowsOpMetrics.doc)
uploaded
I think this will be very useful, and thanks for the Proposal, Fred. But
metrics is only part of the story. Are we going to do per-operation
state and status? Are we going to do per-operation message processing
state and notifications? (The last item may be possible already,
if you specify the operation in your xpath). I know those weren't
explicitely in the action item, so I am asking if we can add them to the
action item, or write a new action item.
Regards,
David E Cox
Fred Carter <fred.carter@amberpoint.com>
10/17/2005 01:21 PM
Please respond to
fred.carter |
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| wsdm@lists.oasis-open.org
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cc
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Subject
| Re: [wsdm] Groups - OperationMetricsProposal
(MowsOpMetrics.doc) uploaded |
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Good catch. Operation + ${metric} it is
Thus quoth Wilson, Kirk D (~ 10/15/2005 11:24 AM ~)...
I think there might be a processing problem in the proposal as it current
stands. When encountering a <NumberOfRequests> element, the
client parser would have to check the attributes to determine whether the
data is at the service level or the operation level. That might produce
a backwards compatibility problem for current implementations.
I would recommend that the OperationMetrics properties also be prefaced
with “Operation”, i.e. <OperationNumberOfRequests>, etc.
Kirk Wilson
Architect, Development
Office of the CTO
802 765-4337
-----Original Message-----
From: Fred Carter [mailto:fred.carter@amberpoint.com]
Sent: Friday, October 14, 2005 2:27 PM
To: wsdm@lists.oasis-open.org
Subject: Re: [wsdm] Groups - OperationMetricsProposal (MowsOpMetrics.doc)
uploaded
Thus quoth Wilson, Kirk D (~ 10/14/2005 11:16 AM ~)...
I haven’t had time to read Fred’s proposal yet (weekend reading), but
isn’t another alternative just to handle OperationMetrics as an “empty”
capability (extension of MOWS metrics) and allow the designer to specify
GEDs as part of an service specific extension for each metric property
for each operation of interest within that service (a bit ugly and tedious)?
indeed it is. That's effectively, albeit with even fewer restrictions,
the alternative mentioned below the query resource properties. It
would require each new manageable endpoint to specify their own schema,
I think, or run entirely within the extensibility rules. Then, though,
I think you need to figure out how to link them back to this capability...
By type? By some other, still-to-be-named attribute?
I thought about this. We could do it using, say, the operationName
attribute as a key meaning that this is an operation metric. Or use
the mows:operation{integer,duration} type, I suppose. That
would work as well. Difference is that they caller will have to examine
the schema to 1) figure out if there are op metrics, and 2) to figure out
what their names are. In this case, the names are known, the operation's
names come from the wsdl, but you either have to get the whole prop doc
and mung or rely on the server to do it (its having implemented queryResourceProps).
Unclear to me which is preferred...
Any thoughts on this? (Just as a conceptual possibility if not a
practical one.)
Kirk Wilson
Architect, Development
Office of the CTO
802 765-4337
-----Original Message-----
From: Tony Gullotta [mailto:tony.gullotta@soa.com]
Sent: Friday, October 14, 2005 1:59 PM
To: wsdm@lists.oasis-open.org
Subject: RE: [wsdm] Groups - OperationMetricsProposal (MowsOpMetrics.doc)
uploaded
I see. So we have to use QueryResourceProperties because GetResourceProperty
won't be able to distinguish between operations.
From: Fred Carter [mailto:fred.carter@amberpoint.com]
Sent: Friday, October 14, 2005 10:52 AM
To: Tony Gullotta
Cc: wsdm@lists.oasis-open.org
Subject: Re: [wsdm] Groups - OperationMetricsProposal (MowsOpMetrics.doc)
uploaded
Well, it's just a properties document. So whatever query mechanism
for that would have to do -- that's a WSDM limit, I think. So this
would use the QueryResourceProperties optional call with a query expression
(dialect XPath) of
*[namespace-uri()="this capability's namespace" and ./@operationName="desiredOperation"]
(or something like that)
An alternative, where the query function isn't required, would be to name
the operation metrics with the operation name. However, I think we'd
have a hard time coming up with a schema then (we'd need a meta schema
:-) ), since we wouldn't have the metric names at spec time (since the
operations vary quite a bit, obviously).
At a higher level, the choice at some level, was either individual
metrics or a more general property document element for the operation --
that would contain all the stuff about an operation. This seemed
counter to how we've done capabilities, so I separated it this way.
The other choice involves a capability (or some combination thereof) that
instituted a subdocument for operation properties. I wasn't quite
sure if that was easily representable, so...
Thus quoth Tony Gullotta (~ 10/14/2005 10:34 AM ~)...
How would I request the NumberOfRequests metric for just one operation?
-----Original Message-----
From: fred.carter@amberpoint.com
[mailto:fred.carter@amberpoint.com]
Sent: Friday, October 14, 2005 10:22 AM
To: wsdm@lists.oasis-open.org
Subject: [wsdm] Groups - OperationMetricsProposal (MowsOpMetrics.doc)
uploaded
This document proposes to extend the MUWS metrics capability, adding an
operation name &, optionally, portType, attributes to the current set
of
MOWS metrics. As an example, we could report number of requests for
the
sample operation as
<NumberOfRequests operationName="sample" ...>34</NumberOfRequests>
<NumberOfRequests operationName="anotherSample"
...>3</NumberOfRequests>
In this environment, any number of numberOfRequests is permitted, though
they must have different operationNames, or, if the same, different
portTypes, as these are the distinguishing characteristics.
Document current shows changes based on the MOWS Metrics capability
since it's pretty analogous.
It occurred to me that this is not all that hard, so we may be able to
fit it in (as was some folks recollection of the plan). My apologies
to
Bryan as I think we were supposed to collaborate, but he's out of town
now, and I'll be out much of next week.
Feel free to shoot away on the list!
/fred
-- fred carter
The document named OperationMetricsProposal (MowsOpMetrics.doc) has been
submitted by fred carter to the OASIS Web Services Distributed
Management
(WSDM) TC document repository.
Document Description:
Operation Metrics Proposed Text
View Document Details:
http://www.oasis-open.org/apps/org/workgroup/wsdm/document.php?document_
id=14904
Download Document:
http://www.oasis-open.org/apps/org/workgroup/wsdm/download.php/14904/Mow
sOpMetrics.doc
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-OASIS Open Administration
--
Fred Carter / AmberPoint, Inc.
mailto:fred.carter@amberpoint.com
tel:+1.510.433.6525 fax:+1.510.663.6301
--
Fred Carter / AmberPoint, Inc.
mailto:fred.carter@amberpoint.com
tel:+1.510.433.6525 fax:+1.510.663.6301
--
Fred Carter / AmberPoint, Inc.
mailto:fred.carter@amberpoint.com
tel:+1.510.433.6525 fax:+1.510.663.6301
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