more performance work?

[Jelmer Vernooij]

Am Donnerstag, den 08.11.2007, 07:04 +1100 schrieb Robert Collins:
> On Wed, 2007-11-07 at 20:45 +0100, Jelmer Vernooij wrote:
> I don't see any reasons why that's the case for tracking cherrypicks,
> > tracking copies or keyword expansion though. 
> tracking copies such that it does the right thing requires deep changes
> in inventories. fileid:revisionid is not sufficient in our model to deal
> with copies.
I mean tracking file copies - not necessarily about actually using that data yet. Doesn't necessarily have to be the fastest way of accessing that data, but at least means we don't lose that historic data.

> Cherrypicks take two forms - partial commits of merges and commits of
> partial merges; to make merge, missing and log DTRT after a cherrypick
> you need a more sophisticated concept of the revision graph. 
But you can store that data when doing a cherry pick at the moment so you can use it in your revision graph later on when you support that feature. 

> mmm I guess I'm really saying 'just recording and not using is
> pointless, because you won't record the right data'. (And its not
> obvious what the right data is until you have an implementation that
> *uses* it).
That's a good point, though s/data/format imo.

You do know what data to record in the case of eol or cherrypicks - just not the optimal, usable format yet. You can store sufficient data so that a new format can use it and convert to something usable during an upgrade.

Reconsidering after this discussion, I think that what I'd like to see is support for "dormant" properties. Allowing these features to be represented in a simple representation in older formats. That means they wouldn't require a watershed upgrade but a regular upgrade and would allow for downgrades. It also means we don't lose certain historical data yet, although we can't use it.

I understand this isn't really trivial, but it would be really nice if this could be pulled off. 

Cheers,

Jelmer
-- 
Jelmer Vernooij <jelmer at samba.org> - http://samba.org/~jelmer/
Jabber: jelmer at jabber.fsfe.org