Re: caching commit patch-ids for fast git-cherry

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: May 29, 2008, 17:13 UTC
Message-ID: <alpine.DEB.1.00.0805291809340.13507@racer.site.net>
In-Reply-To: <7f9d599f0805291001mdbb4b42q6f3a1b79bc9bc4e9@mail.gmail.com>

Hi,

On Thu, 29 May 2008, Geoffrey Irving wrote:

Show 12 quoted lines

> I'm planning to use cherry picking to manage long term syncing between 
> cvs/perforce and git repositories.  This means I'll have scripts running 
> git-cherry between branches with hundreds of uncommon commits, and I 
> want git-cherry to be much, much, faster.
> 
> It looks like I can do this by caching commit->patch-id pairs from
> commit_patch_id() in patch-ids.c to a file, say
> $GIT_DIR/commit-patch-id-cache.  The file would be binary and append
> only, and could be blown away if .  Any suggestions / concerns before
> I write this?  Is there any reusable efficient map code for storing
> the commit->patch-id map, or should I just mirror the blocked storage
> + binary search used for struct patch_ids?

I would store the stuff sorted, so that the lookup is fast, generation less so.

For inspiration, you might want to look at the "notes" branch in my personal fork:

http://repo.or.cz/w/git/dscho.git?a=shortlog;h=refs/heads/notes

Hth, Dscho