brainstorming - what to do with annotations

[Robert Collins]

On Mon, 2007-09-10 at 13:14 +0100, Michael Hudson wrote:
> Robert Collins wrote:
> > So I have my initial commit work committing mozilla in 1m48 wall clock
> > time.
> > 
> > On my laptop tar czf is 0m38. I'm aiming for twice that - 1m16.
> > 
> > The 1m48 is reached in part by disabling annotation caching. I think it
> > would be nice to find some way of still having fast annotations.
> 
> Speaking with my loggerhead hat on, yes please :)

I'm adamant that we be able to run packs with no annotations. This could
take several forms:
 - two pack formats, one annotated, one not annotated.
 - a per-commit knob and packs support annotated-or-not per text.
 - no texts annotated, but separate annotation-cache of some form (e.g.
a separate cache, perhaps also in the packs of the repository, or
perhaps a separate collection of packs (to allow trivial trimming)).

As Aaron notes we often generate the data needed to annotate as part of
delta generation, so preserving that work would be nice.

> > e.g.
> > mpdiffs give us annotations for free don't they? But what about ghosts
> > and shallow repositories -  do they still have full texts, and when
> > there is a full text in an mpdiff stream is it annotated? Can we store
> > annotations in a different way thats more efficient? ....
> 
> I'm not sure what the consequences of not storing annotations at commit
> time are.  Could they be computed later and still cached?

Several things. Annotate gets slower unless cached. Ghosts will prevent
annotations referring to the ghost records. But we also get to do less
work (depending on the delta form). Delta against a parent text is also
useful for annotation; delta against a non-parent text is not.

-Rob
-- 
GPG key available at: <http://www.robertcollins.net/keys.txt>.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
Url : https://lists.ubuntu.com/archives/bazaar/attachments/20070911/ccde0b86/attachment.pgp