RE: Bad performance when using git log --parents (used by gitk)

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Apr 2, 2019, 18:20 UTC
Message-ID: <nycvar.QRO.7.76.6.1904022017510.41@tvgsbejvaqbjf.bet>
In-Reply-To: <HE1PR0702MB378867A3A8F81CB475882A28B0560@HE1PR0702MB3788.eurprd07.prod.outlook.com>

Hi Björn,

On Tue, 2 Apr 2019, Björn Pettersson A wrote:

Show 8 quoted lines

> Thanks for a quick reply (with lots of details).
>
> Hitting some quadratic complexity algorithm explains why the "degradation"
> is so huge. And if I understand it correctly we are more or less "unlucky"
> to hit such access patterns more often in the new repo.
>
> Anyway, nice to see that you already have some ideas regarding how to
> improve this.

In the meantime, maybe the commit graph feature can help you?

	git config --global core.commitGraph true
	git config --global gc.writeCommitGraph true
	git commit-graph write --reachable

The idea being that the commit graph extracts a lot of information pre-emptively and makes the lookup of those bits faster than unpacking the commits all the time.

Ciao, Johannes