Re: [Monotone-devel] cvs import

> On Wed, Sep 13, 2006 at 04:42:01PM -0700, Keith Packard wrote:
> > However, this means that parsecvs must hold the entire tree state in
> > memory, which turned out to be its downfall with large repositories.
> > Worked great for all of X.org, not so good with Mozilla.
>
> Does anyone know how big Mozilla (or other humonguous repos, like KDE)
> are, in terms of number of files?

>
> A few numbers for repositories I had lying around:
>   Linux kernel -- ~21,000
>   gcc -- ~42,000
>   NetBSD "src" repo -- ~100,000
>   uClinux distro -- ~110,000
>
> These don't seem very indimidating... even if it takes an entire
> kilobyte per CVS revision to store the information about it that we
> need to make decisions about how to move the frontier... that's only
> 110 megabytes for the largest of these repos.  The frontier sweeping
> algorithm only _needs_ to have available the current frontier, and the
> current frontier+1.  Storing information on every version of every
> file in memory might be worse; but since the algorithm accesses this
> data in a linear way, it'd be easy enough to stick those in a
> lookaside table on disk if really necessary, like a bdb or sqlite file
> or something.
>
> (Again, in practice storing all the metadata for the entire 180k
> revisions of the 100k files in the netbsd repo was possible on a
> desktop.  Monotone's cvs_import does try somewhat to be frugal about
> memory, though, interning strings and suchlike.)
>
> -- Nathaniel
>
> --
> When the flush of a new-born sun fell first on Eden's green and gold,
> Our father Adam sat under the Tree and scratched with a stick in the mould;
> And the first rude sketch that the world had seen was joy to his mighty heart,
> Till the Devil whispered behind the leaves, "It's pretty, but is it Art?"
>   -- The Conundrum of the Workshops, Rudyard Kipling
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