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Re: svn cleanup and unreferenced pristines

From: Vincent Lefevre <vincent-svn_at_vinc17.net>
Date: Mon, 13 Jan 2014 04:16:39 +0100

On 2014-01-13 03:51:08 +0100, Branko Čibej wrote:
> On 13.01.2014 03:43, Vincent Lefevre wrote:
> > I meant deltas like in the repository (but see below).
>
> When you say "delta" you have to also define "against what". Otherwise
> it's just a not very efficient compression algorithm.

Against another pristine. Then there are several ways to do that,
just like BDB and FSFS used different methods for the repository.
But any of them would be more memory efficient than no deltas at
all (like currently).

> >>> Caching the repository or a part of the repository may be better.
> >> That's exactly what pristines are.
> > Not in a memory efficient way! For one of my working copy, a
> > "svn cleanup" reduced the working copy size by about 2 GB, while
> > the repository is only 1.5 GB.
>
> Indeed. The point of the whole exercise is to invent an efficient way of
> storing (or omitting, when appropriate) pristines. Saying "delta" or
> "cache the repository" is just hand-waving and doesn't really contribute
> to a solution.

For machines with enough disk space, caching the whole repository
could be a solution. This is known not to be a bad one, since
this is more or less what distributed SCM's do. For machines
with little disk space, users may want to avoid storing any
unreferenced pristines anyway.

-- 
Vincent Lefèvre <vincent@vinc17.net> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
Received on 2014-01-13 04:17:19 CET

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