From: Stewart Smith <stewart@flamingspork.com>
To: martin f krafft <madduck@madduck.net>, notmuch@notmuchmail.org
In-Reply-To: <20100217012101.GD8249@lapse.rw.madduck.net>
References: <20100215002914.GA22402@flamingspork.com>
	<20100217012101.GD8249@lapse.rw.madduck.net>
Date: Thu, 18 Feb 2010 10:56:53 +1100
Message-ID: <87ljerju0q.fsf@willster.local.flamingspork.com>
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Subject: Re: [notmuch] Mail in git
Precedence: list

On Wed, 17 Feb 2010 14:21:01 +1300, martin f krafft <madduck@madduck.net> w=
rote:
> What I am wondering is if (explicit) tags couldn't be represented as
> tree-objects with this.
>=20
>   evenless-link   =E2=80=94 link a message object with a tree object
>   evenless=E2=80=93unlink =E2=80=93 unlink a message object from tree obj=
ect
>     [replaces evenless-unlink]

I think it could get expensive for tags with lots of messages.

With my fast-import script, doing the commit (that
referenced... umm.. 800,000+ objects took a *very* long time).

As far as I understand it, the tree object is stored in full and space
is only reclaimed during repack (due to delta compression).

So if you, say, had the entire history of a high volume list such as
linux-kernel, adding messages could get rather expensive if you
auto-tagged (or autotagged messages with patches or whatever).

> messages would then be deleted whenever using git-gc.
>=20
> No idea how this would sync if we don't keep ancestry. Otoh, it
> would probably not be very expensive to do just that.

If we keep ancestry though, we are reusing existing working code for
backup (git-pull :)

Keep in mind that with my tests, the Maildir in git is about a quarter
to a fifth of the size of it in Maildir... so a bit of extra usage per
message isn't as dramatic as it may sound.

> Is it possible to find out all trees that reference a given object
> with Git in constant or sub-linear time?

I don't think so.... but I'm not sure.

--=20
Stewart Smith