Re: [Monotone-devel] State of mtn - CVS syncing

[Daniel Carosone]

On Wed, May 16, 2007 at 11:33:22AM +1000, William Uther wrote:
> 
>  On 16/05/2007, at 10:43 AM, Daniel Carosone wrote:
> 
> > On Tue, May 15, 2007 at 11:52:59AM +1000, William Uther wrote:
> >>  It stores the sync information in attributes, using a cert to
> >>  mark which revisions are actually in sync.
> >
> > Minor nit.. I maintain skepticism about the actual need for this cert,
> > vs being able to derive that information purely from the state of the
> > graph, but I have no argument with the convenience of using the cert.
> 
>  Well, you might be able to derive this cert from the sync information:
>    - loop over all files
>    - get the attr telling you with CVS rev this should be
>    - get the corresponding CVS rev
>    - check the files match
>  If all files match, then you're in sync. 

I think it's simpler than that, and that it's a completely offline
operation (no need to check with cvs).  Basically, the content should
not have changed more recently than the attr.  Furthermore, I beleive
you can determine this (at least from within core mtn) from the roster
markings for each scalar, rather than by walking back up the tree for
each rev.

Even so, and especially from the viewpoint of an external program
without ready access to internal markings, checking a cert is
certainly more convenient.

Perhaps this redundancy is something that could be validated in (say)
db check, rather than something we use in normal operation just to
avoid generating a cert.

Just to be clear, I'm not picking on the implementation, just trying
to tease out the precise details of the algorithm.  If it gives us a
second formal definition of the assertion the cert is making (and
we're relying on as a cache), which can be checked for consistency,
that's a good thing.

> > Could you describe these problems in more detail?
> 
>  Not really.  I seem to be able to add individual files ok.  I seem to be 
>  able to add directories ok.

Ok, so it's still in the realm of undiagnosed behaviour; that's what I
suspected you weren't quite saying.. :-) I'll see if I can make any
further useful observations in my own testing.

Thanks again!

--
Dan.

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