[Oslc-pm] should ems:observes be required for PerformanceMonitoringRecords

[Julianne Bielski]

On today's workgroup call (and afterwards w/Janet who wasn't able to make 
the call) we discussed whether the ems:observes predicate of the 
PerformanceMonitoringRecord resource should have a 'zero-or-many' 
cardinality or a 'one-or-many' cardinality.

John was okay either choice, and I asserted it should be required so that 
client code needing metrics on resources could query for resources of type 
'PerformanceMonitoringRecord' and expect to find observations about it.

Janet thought it should be optional because some resources, like 
crtv:Database may have predicates from the perfmon vocabulary 
(pm:tableReorgNeeded) but which aren't numeric, so aren't referenced from 
an ems:Measure, and hence wouldn't need ems:observes.

We have an implementation right now that has a resource with an rdf:type 
PerformanceMonitoringRecord and no ems:observes, and other resources with 
ems:observes predicates and no rdf:type PerformanceMonitoringRecord.

Opinions?


-- Regards,

Julianne Bielski, STSM
ITM Core Chief Architect
Tivoli, IBM Software Group
tel: (919) 224-1170      (T/L) 687-1170
e-mail: bielsk at us.ibm.com

"All growth is a leap in the dark, a spontaneous unpremeditated act 
without benefit of experience." — Henry Miller
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