Hi Mark,
----- Original Message -----
> [...]
>
> I've been thinking about this topic - not just for string valued metrics
> (btw: hinv.map.scsi is another one in this class), but also for discrete
> integer typed metrics, such as hinv.ndisk etc.
Its also a bit like the proc.psinfo.environ case that Martins came across,
I think.
> These metrics need to be logged more than "once"; rather more like "when
> changed".
> Once logged, they retain their discrete value (string or integer) until
> logged
> again with a new value. As an alternative to pmie monitoring these metrics
> and telling
> pmlogger to log them again via pmlc, maybe pmlogger could just maintain a
> cache
> (suitably indexed for efficiency) - when a discrete metric/instance/value
> with logging
> frequency of "when changed" changes, write it to the log again.
>
I guess that would involve fetching these metrics like normal, but modifying
the pmResult to drop them, before writing to disk. A bit like the inverse of
derived metrics, where the pmresult is added to with new metrics.
Might need a new pmlogger-language grouping keyword to indicate this new kind
of on-change-only behaviour for certain metrics? (Or, automatically done for
all string-type metrics?)
cheers.
--
Nathan
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