On 10/02/16 07:33, Frank Ch. Eigler wrote:
... Ken, what do you think about a derived-metric facility
for this?
mounted_filesys.free = map_indom(filesys.free, filesys.mountdir)
Not sure. map_indom() is more like a declarative operator than an
method (a la the other foo() thingies we support).
This is almost getting into the realm of pmlogrewrite(1) where we're
asking for metadata changes on the fly ... I'm not convinced of the
bang-for-buck proposition here, as it would be a big change for derived
metrics (grammar, but worse put derived metrics clutter on almost every
PMAPI code path, whereas the clutter is confined to the pmFetch code
path at the moment) and this seems to be addressing a rare corner case.
If the instance domains are _really_ equivalent, then an alternative
would be for the PMDA implementation to export _two_ groups of metrics,
one for the first instance domain, and the second for the other instance
domain ... the end user could then choose the naming convention they prefer.
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