Re: [pcp] logger PMDA review

[Ken McDonell <kenj at internode dot on dot net>]

On Mon, 2011-04-18 at 23:08 -0400, Josef 'Jeff' Sipek wrote:
> ...
> > 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.

Good point Jeff.

Either the internal instance id needs to be in the configuration file
and needs to be kept the same for each external log file ... David
already has something like this in the PMNS prefix that is held in the
configuration file, this could be replaced by a small integer to be used
as the internal instance id (the external instance id could be the
pathname to the logfile).

Or the PMDA needs some persistent state to save the mapping from
internal to external instance identifiers ... refer to man pmdacache for
a set of routines to do _just_ _this_ on behalf of a PMDA.