From: Patrick Steinhardt <ps@pks.im>
Date: Tue, 24 Feb 2026 08:15:12 GMT
Subject: Re: [PATCH 8/8] builtin/maintenance: use "geometric" strategy by default
Message-ID: <aZ1eENpDpagp77dN@pks.im>
In-Reply-To: <aZyAOsRX5484naIU@denethor>

On Mon, Feb 23, 2026 at 10:48:59AM -0600, Justin Tobler wrote:
> On 26/02/20 11:15AM, Patrick Steinhardt wrote:
> > The git-gc(1) command has been introduced in the early days of Git in
> > 30f610b7b0 (Create 'git gc' to perform common maintenance operations.,
> > 2006-12-27) as the main repository maintenance utility. And while the
> > tool has of course evolved since then to cover new parts, the basic
> > strategy it uses has never really changed much.
> > 
> > It is safe to say that since 2006 the Git ecosystem has changed quite a
> > bit. Repositories tend to be much larger nowadays than they have been
> > almost 20 years ago, and large parts of the industry went crazy for
> > monorepos (for various wildly different definitions of "monorepo"). So
> > the maintenance strategy we used back then may not be the best fit
> > nowadays anymore.
> > 
> > Arguably, most of the maintenance tasks that git-gc(1) does are still
> > perfectly fine today: repacking references, expiring various data
> > structures and things like tend to not cause huge problems. But the big
> > exception is the way we repack objects.
> > 
> > git-gc(1) by default uses a split strategy: it performs incremental
> > repacks by default, and then whenever we have too many packs we perform
> > a large all-into-one repack. This all-into-one repack is what is causing
> > problems nowadays, as it is an operation that is quite expensive. While
> > it is wasteful in small- and medium-sized repositories, in large repos
> > it may even be prohibitively expensive.
> > 
> > We have eventually introduced git-maintenance(1) that was slated as a
> > replacement for git-gc(1). In contrast to git-gc(1), it was much more
> > flexible as it is structured around configurable tasks and strategies.
> > And while it knows about the "incremental" strategy that we may use for
> > scheduled maintenance when configured via Scalar, its default still is
> > to use git-gc(1) in the background.
> 
> I'm a tad bit confused here. git-gc(1) by default uses an
> "incremental/all-into-one" strategy and it is my understanding that this
> is what git-maintenance(1) is currently using. Is there also another
> "incremental" strategy for git-maintenance(1)?

There are three strategies right now:

  - "gc", which is the current default strategy that uses git-gc(1) to
    perform the incremental packs followed by the all-into-one repacks.

  - "incremental", which is set up by `git maintenance start`. This
    strategy never performs the all-into-one repacks, and it instead
    creates packs of a fixed upper size.

  - "geometric", which is the strategy that'll become the new default.

I'll try to clarify this a bit.

Patrick