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From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: "brian m. carlson" <sandals@crustytoothpaste.net>,
	 "D. Ben Knoble" <ben.knoble@gmail.com>,
	 Emily Shaffer <nasamuffin@google.com>,
	 Christian Fredrik Johnsen <cfj@johnsen.no>,
	 "git@vger.kernel.org" <git@vger.kernel.org>
Subject: Re: [Feature Request] Allow batch removal of remotes with 'git remote remove'
Date: Wed, 22 Jan 2025 08:23:09 -0800	[thread overview]
Message-ID: <xmqqed0uyg0i.fsf@gitster.g> (raw)
In-Reply-To: <20250122030832.GA3322144@coredump.intra.peff.net> (Jeff King's message of "Tue, 21 Jan 2025 22:08:32 -0500")

Jeff King <peff@peff.net> writes:

> On Wed, Jan 22, 2025 at 02:24:38AM +0000, brian m. carlson wrote:
>
>> Because `git remote remove` will remove remote-tracking branches and
>> their reflogs, we typically will want to do that all at once in a single
>> ref transaction, and hence in one command.  Not doing so performs very
>> poorly (as does, notably `git remote rename`[0]) when all of the refs are
>> packed.  If you have a large number of remotes to delete and a large
>> number of total refs, this will perform really badly indeed, since the
>> operation of rewriting the packed-refs file becomes quadratic.
>> 
>> The removal of the remote-tracking branches is also the reason that
>> editing the config isn't sufficient, either.
>
> I think the config update is probably quadratic, too (in the number of
> remotes). Each one is going to rewrite the whole config file, minus its
> matching section. But a "remove" operation that took multiple remotes
> could do it all in a single pass.
>
> If somebody does implement "remote remove" that takes multiple names, I
> hope they'll refactor to do all of the operations in a single pass, and
> not just loop on builtin/remote.c:rm() internally.
>
> Probably git-config could stand to learn similar tricks, too. There is
> "--remove-section", but I don't think you can pass multiple sections
> (and it's likewise quadratic).

Thanks for bringing up the performance aspect and where the problem
lies in the current implementation.



  reply	other threads:[~2025-01-22 16:23 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-20 23:06 [Feature Request] Allow batch removal of remotes with 'git remote remove' Christian Fredrik Johnsen
2025-01-21 21:10 ` Emily Shaffer
2025-01-21 21:32   ` D. Ben Knoble
2025-01-21 22:38     ` Junio C Hamano
2025-01-22  2:24     ` brian m. carlson
2025-01-22  3:08       ` Jeff King
2025-01-22 16:23         ` Junio C Hamano [this message]
2025-01-22  9:40       ` Patrick Steinhardt

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