From: Jeff King <peff@peff.net>
To: Mike Hommey <mh@glandium.org>
Cc: Johan Herland <johan@herland.net>, git@vger.kernel.org
Subject: Re: "git notes show" is orders of magnitude slower than doing it manually with ls-tree and cat-file
Date: Tue, 25 Nov 2014 20:00:51 -0500 [thread overview]
Message-ID: <20141126010051.GA29830@peff.net> (raw)
In-Reply-To: <20141126004242.GA13915@glandium.org>
On Wed, Nov 26, 2014 at 09:42:42AM +0900, Mike Hommey wrote:
> I have a note tree with a bit more than 200k notes.
>
> $ time git notes --ref foo show $sha1 > /dev/null
> real 0m0.147s
> user 0m0.136s
> sys 0m0.008s
>
> That's a lot of time, especially when you have a script that does that
> on a fair amount of sha1s.
IIRC, the notes code populates an in-memory data structure, which gives
faster per-commit lookup at the cost of some setup time. Obviously for a
single lookup, that's going to be a bad tradeoff (but it does make sense
for "git log --notes"). I don't know offhand how difficult it would be
to tune the data structure differently (or avoid it altogether) if we
know ahead of time we are only going to do a small number of lookups.
But Johan (cc'd) might.
-Peff
next prev parent reply other threads:[~2014-11-26 1:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-26 0:42 "git notes show" is orders of magnitude slower than doing it manually with ls-tree and cat-file Mike Hommey
2014-11-26 1:00 ` Jeff King [this message]
2014-11-26 1:24 ` Jeff King
2014-11-26 1:34 ` Jeff King
2014-11-26 2:30 ` Mike Hommey
2014-11-26 4:49 ` Jeff King
2014-11-26 2:25 ` Mike Hommey
2014-11-26 4:46 ` Jeff King
2014-11-26 11:46 ` Johan Herland
2014-11-26 12:30 ` Mike Hommey
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