Re: [PATCH] pack-objects: re-validate data we copy from elsewhere.

From: Linus Torvalds <torvalds@osdl.org>
Date: Sep 2, 2006, 18:43 UTC
Message-ID: <Pine.LNX.4.64.0609021138500.27779@g5.osdl.org>
In-Reply-To: <7vd5ae3ox2.fsf@assigned-by-dhcp.cox.net>

On Fri, 1 Sep 2006, Junio C Hamano wrote:

Show 5 quoted lines

> 
> But "git repack -a -d", which you now consider almost being
> free, in the recent kernel repository counts 300k objects, and
> reuses 298k objects or so.  That means we expand and recompress
> that many objects, totalling 120MB.

Sure. Do we have data for how expensive that is (ie did you apply the patch and time it)?

I'd rather be really safe by default, and then if somebody knows to trust their archive, maybe add a "--fast" flag (or even a "core.reliablepack" config option) to disable it for people who have backups and think their machines are infallible - or have slow CPU's..

For me, performance has always been one of the primary goals, but being able to trust the end result has been even _more_ primary. A lot of the design has centered around not doing things that are unsafe (eg the whole "never ever re-write an object" thing was obviously a big part of the design, and a lot of it is about being able to do things quickly _without_ having to do slow things like fsync).

			Linus

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