Re: [Gnu-arch-users] Preliminary Arch Cache available

[David Allouche]

On Tue, 2004-09-14 at 07:51 -0400, Aaron Bentley wrote:
> I'm not sure whether you're reading me correctly.  There should 
> definitely be a way to fill a version by itself.  I'm just wondering 
> what that "filling a version" should involve.
> 
> Should we grab all available cacherevs?  Should we ensure the version 
> has one cacherev?  What if the version has an ancestor in the cache with 
>   a cacherev?  Does it matter whether that ancestor's in the same 
> archive, since the cache spans multiple archives?
> 
> Questions about what versions to mirror strike me as different 
> questions, and the archive-mirror stuff would be a good starting point.

Ha. Hum. Indeed.

Since the cache has significantly different usage patterns than mirrors,
there might be an opportunity for being more lazy on some things
(because data is present in the revlib too) and more greedy on others.

Right now I would be happy if filling a version behaved much like
mirror. Updating all cachedrevs is currently too expensive, and not
grabbing new in-versions cachedrevs could be a problem with very active
versions. The presence of in-versions cachedrevs is an important
optimisation hint.

A simple approach would be to behave as if cachedrevs were _not_
transient. Fetch cachedrevs in revisions where the presence/absence of
the cachedrev is not known.

No deep rationale for that. The mirroring behaviour is simple, let's
just reuse it until we have a clear idea of what can be improved.

-- 
                                                            -- ddaa