Re: [pcp] logger PMDA review

[Josef 'Jeff' Sipek <jeffpc at josefsipek dot net>]

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.

-- 
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