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Re: [pcp] logger PMDA review
On Tue, Apr 19, 2011 at 12:28:08PM +1000, Ken McDonell wrote:
> On Mon, 2011-04-18 at 13:24 -0500, David Smith wrote:
> > ...
> >
> > > - might want to revisit using dynamic metric names versus metric
> > > instances, dynamic names generally a bit more complicated to code.
> > > (removes need to restrict/check names in Install too, although they
> > > do need to be unique)
> >
> > On the dynamic metric name issue versus metric instances issue, I looked
> > into that a bit. I was considering making each logfile a separate
> > instance. However, I couldn't figure out from the client point of view
> > how to "subscribe" to only one instance of a particular metric. It
> > seemed wrong to make the client consume data for multiple files when it
> > was only interested in one file's data.
> >
> > If I'm wrong here, I'll be happy to rethink.
> >
>
> Clients use pmAddProfile and pmDelProfile to allow selection of one,
> some or all of the instances for each instance domain ... once made, the
> profile remains "sticky" for each subsequent pmFetch ... the default is
> for pmFetch to return all instances for all instance domains. This is
> how pmval -i instance or pmevent metric[instance] works.
>
> I suspect an instance domain is going to be a cleaner long-term solution
> than dynamic metrics in the PMNS for your case of multiple log files
> being processed.
Will using instance domains become an issue if one decides to merge several
log files? The result of a merge may end up useless if the instance ids
changed between the two log files.
Jeff.
--
If I have trouble installing Linux, something is wrong. Very wrong.
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