Re: git-index-pack really does suck..

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Apr 3, 2007, 22:14 UTC
Message-ID: <Pine.LNX.4.64.0704031511580.6730@woody.linux-foundation.org>
In-Reply-To: <alpine.LFD.0.98.0704031735470.28181@xanadu.home>

On Tue, 3 Apr 2007, Nicolas Pitre wrote:

Show 8 quoted lines

> > 
> > It could be as simple as just the index file itself. That's 11MB for the 
> > kernel. Imagine if the index file was 20 times bigger - 200MB of memory 
> > paged in with bad access patterns just for unnecessary lookups.
> 
> Again that presumes you have to page in the whole index, which should 
> not happen when pulling (much smaller packs) and with a better lookup 
> algorithm.

Actually, since SHA1's are randomly distributed, together with the binary search, you probably *will* pull in the bulk of the index, even with a fairly small set of SHA1's that you check.

> Make it conditionnal on --stdin then.  This covers all cases where we 
> really want the secure thing to happen, and the --stdin case already 
> perform the atomic rename-and-move thing when the pack is fully indexed.

I don't care *what* it is conditional on, but your arguments suck. You claim that it's not a normal case to already have the objects, when it *is* a normal case for alternates, etc.

I don't understand why you argue against hard numbers. You have none of your own.

		Linus