From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 07 Dec 2015 22:56:33 GMT
Subject: Re: best practices against long git rebase times?
Message-ID: <xmqqmvtllvfi.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20151207210212.GF30203@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

> You're computing the patch against the parent for each of those 3000
> commits (to get a hash of it to compare against the single hash on the
> other side). Twelve minutes sounds long, but if you have a really
> gigantic tree, it might not be unreasonable.
>
> You can also try compiling with "make XDL_FAST_HASH=" (i.e., setting
> that option to the empty string). Last year I found there were some
> pretty suboptimal corner cases, and you may be hitting one (we should
> probably turn that option off by default; I got stuck on trying to find
> a hash that would perform faster and never followed up[1].
>
> I doubt that is your problem, but it's possible).
>
> -Peff
>
> [1] http://thread.gmane.org/gmane.comp.version-control.git/261638

I vaguely recall having discussed caching the patch-ids somewhere so
that this does not have to be done every time.  Would such an
extension help here, I wonder?