Hi Dave,
----- Original Message -----
> [...]
> If you already know how pmchart works with multiple archives today, then you
> can skim this next bit or, even better, correct me where my understanding is
> incorrect.
(looks spot on to me)
> pmchart currently allows the specification of more than one archive on the
> command line via multiple -a options and via additional untagged sources on
> the command line. However, it treats each specified archive as a separate
> source of metrics. When a view is opened, the user is asked which source the
> view should be applied to. Each archive is therefore opened using a separate
> context. So while metrics from more than one archive can be viewed,
> multiple-archives cannot be viewed as a single source of metrics within a
> single view. One limitation of this is that metrics cannot currently be
> scaled across multiple archives within the same view (PM_MODE_INTERP).
*nod* - so far, its been all about allowing archives from multiple hosts.
BTW, pmie is in a similar boat, if that helps at all with your current
work (non-GUI tool - maybe useful, and also accepts a comma-separated
archive list IIRC - also only with the idea of supporting multiple hosts
archives, so far).
> 1. My first idea was to change the current behaviour, so that multiple
> archives would be automatically treated as a single source. It didn't
> take me long to realize that, while this might be valuable, it would
> invalidate some current use scenarios which are equally valid. For
> example, viewing separate archives which are not related in any way in
> separate views using tabs. Automatically treating multiple archives as a
> single source would require that all of the archives are compatible for
> this purpose.
Yep, but also keep in mind incompatible metric semantics between archives of
the same host is a relatively rare situation (and should usually be fixable
via pmlogrewrite). So it may be for the greater good to require compatibility
(the code should still check it of course, and as long as the diagnostics are
good when a fix/rewrite is required, I think it would be OK to auto-join 'em,
esp. if that improves the user interface &| user experience.
> 2. Another idea is to simply allow more than one archive to be selected
> in the UI when opening a view. This would give the user explicit control
> over which of the archives specified on the command line to combine in
> the given view. Single archive views would be supported as before and
> multi-archive views would also now be possible. If a directory is named
> on the command line, then the user could be given the option to include
> all of the archives within it as a whole or to choose individual
> archives from within it.
>
*nod* - and as discussed yesterday, we would tweak the file selection dialog
in this regard - that's a straight forward change IIRC.
cheers.
--
Nathan
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