Alan Grow <agrow@thegotonerd.com> wrote on 04/08/2005 11:43:20 PM:
> Thanks for the design info, that helps a lot. So under FSFS a checkout
of
> the latest revision takes O(lg(N)) on avg instead of O(N) as I had
assumed.
> Still, if you always stored the latest revision of a file in full &
stored the
> transactions as reverse diffs, checkout latest would be an O(1)
operation. Even better.
>
> One could certainly cook up a skip-delta scheme for this. Each
skip-delta
> path terminates in a full copy of the file. A commit overwrites this
copy, but
> not before a reverse delta is added behind it. Perhaps the real problem
is
> more of an architectural clash; I can't say because I'm not an svn
developer.
>
> It just seems to me that checkouts may not be as optimized for the
common
> case as they could be. As an svn admin & very interested follower of the
> project, I've heard "checkouts are slow" quite a lot, and know of at
least one
> large opensource project (open exchange) that have delayed their
migration to
> svn until things improve in that department.
Put on your Asbestos suit and head over to the dev@ list with your ideas
then.
Seriously though, BDB essentially works the way you describe and checkouts
are slow for it as well. This is not the reason that Subversion checkouts
are slow. It is more based on what it is doing in the WC on the client.
Also, you are ignoring that there are other design constraints in place
here. The designers wanted to support a write-only repository and they
also wanted to minimize space usage.
Mark
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Received on Fri Apr 8 18:57:42 2005