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Subject: RE: [wsdm] Question about example of Sec. 4.6 Metrics
I have always been confused over which attributes may/should/must be used with which values of metadata for metrics. It is pretty complicated. I don't think the spec explains it well, but here is how I understand a metric with TimeScope=Interval: - Duration attribute must be used. It specifies the during which data was collected. The length of the interval might be longer than the duration. The metadata CalculationInterval migh offer information about the length of the interval. - ResetAt may be included with the metric value. There is no clear indication of what ResetAt means for an Interval metric, however, I believe it is the time at which the metric was reset. For example, this metric was reset at midnight, but the interval ends at the end of every hour. I am not sure what it means to reset an interval metric, except if the ResetAt value is less than the Duration, which I guess means that the metric was reset in this interval. - LastUpdated should indicate the end of the interval for which the metric represents. LastUpdated - Duration should be the time of the beginning of the interval. CurrentTime - LastUpdated should tell you how far into the next interval the data collection is going. Now if we look at the values used. - The metric was reset ~1 minute 4 seconds before the metric was read. - it was last updated only 0.04 seconds after the reset - the data collection time for this value was more than 24 seconds I agree with you that the times do not make sense. The values indicate that the metric was reset in the middle of data collection. I do not think we should give such an example. In my mind, metrics should extremely rarely or never be reset. This is due to the complications it offers in a multiple manager situation. So, I would set the ResetAt value to be 3 days ago, or a month ago, or some long period relative to the other values. I think it is fine to have the last update time be just a few seconds ago. What I would do for ServiceTime is make it a SnceReset metric and not include the duration. I think ServiceTime is an accumulated time for the total time spent in that service across all requests. So for the example I would set its value to something that is a few hours. My expectation is to request ServiceTime with NumberOfRequests and calculate the time per request myself. This is the behavior that works with multiple managers. If my understanding is incorrect regarding the above, please correct me. Bryan -----Original Message----- From: Mitsunori Satomi [mailto:Mitsunori.Satomi@hds.com] Sent: Wednesday, September 07, 2005 7:56 PM To: email@example.com; firstname.lastname@example.org Subject: [wsdm] Question about example of Sec. 4.6 Metrics Hi Fred and folks, I have one question about the example of "4.6 Metrics" in wsd-wsdm-primer-15.doc. Line #4770 to #4796, e.g. mows-xs:ServiceTime is a "Interval" type metric (not SinceReset) because it has a Duration attribute. And its attributes are written as follows in this example, ResetAt = "2005-06-14T14:24:58.2181944-04:00" LastUpdated="2005-06-14T14:24:58.2582128-04:00" Duration ="PT24.621S" I think that LastUpdated - ResetAt will be nearly equal to the Duration value. But these values of example break this relationship. (And mows-xs:CurrentTime is "2005-06-14T14:25:21.6589722-04:00".) In this example CurrentTime - ResetAt is nearly equal to the Duration, so value of LastUpdated will be adjusted near time of CurrentTime or Duration should be corrected. And I'd like to clarify the meaning of "ResetAt" value in case of "Interval".