Re: [PATCH] remote.c: avoid O(n^2) behavior in match_push_refs by using string_list

From: Junio C Hamano <gitster@pobox.com>
Date: Jul 3, 2013, 18:40 UTC
Message-ID: <7vhagbfpwz.fsf@alter.siamese.dyndns.org>
In-Reply-To: <CA+sFfMeDC=hc7QZhfSuQYsdBPzig5WANeTBhMxFZk=Pusq0QpA@mail.gmail.com>

Brandon Casey <drafnel@gmail.com> writes:

Show 8 quoted lines

> Right.  For repos with few refs on either side, I don't think there
> will be any measurable difference.  When pushing a single ref to a
> repo with a very large number of refs, we will see a very small net
> loss for the time required to prepare the string list (which grows
> linearly with the number of remote refs).  After 2 or 3 refs, we
> should see a net gain.
>
> So we're really just improving our worst case performance here.

... by penalizing the common case by how much? If it is not too much, then this obviously would be a good change.

> ...  But, I don't see a down side to doing the lazy prepare in
> the other loop too, and in fact, it looks like we may be able to avoid
> building the string list when only explicit refspecs are used.  So,
> yeah, we should lazy build in both loops.

OK, so will see a reroll sometime?