Gentoo Archives: gentoo-portage-dev

From: "Michał Górny" <mgorny@g.o>
To: gentoo-portage-dev@l.g.o
Subject: Re: [gentoo-portage-dev] Re: [RFC] gpkg format proposal v2
Date: Mon, 12 Nov 2018 18:01:07
Message-Id: 1542045646.18923.3.camel@gentoo.org
In Reply to: [gentoo-portage-dev] Re: [RFC] gpkg format proposal v2 by Ulrich Mueller
1 On Mon, 2018-11-12 at 18:33 +0100, Ulrich Mueller wrote:
2 > > > > > > On Mon, 12 Nov 2018, Michał Górny wrote:
3 > > On Mon, 2018-11-12 at 17:51 +0100, Fabian Groffen wrote:
4 > > > I'm wondering here, how much sense does it make to compress 2., 3.
5 > > > and/or 4. if you compress the whole gpkg? I have the impression
6 > > > compression on compression isn't beneficial here. Shouldn't just
7 > > > compressing of the gpkg tar be sufficient?
8 > > Please read the spec again. It explicitly says it's not compressed.
9 >
10 > Isn't that the wrong way around? The tar format contains a lot of
11 > padding, so using uncompressed tar for the outer archive would be
12 > somewhat wasteful. Why not leave the inner tar files uncompressed, but
13 > compress the whole binpkg instead?
14
15 Uncompressed tar is mostly suitable for random access. Compressed tar
16 isn't suitable for random access at all.
17
18 With uncompressed tar, it's trivial to access one of the members. With
19 compressed tar, you always end up decompressing everything.
20
21 With uncompressed tar, it's easy to rewrite the metadata (read: apply
22 package updates) without updating the rest. With compressed tar, you'd
23 have to recompress all the huge packages in order to apply updates.
24
25 > Also, what would be wrong with ar? It's a standard POSIX tool, and
26 > should be available everywhere.
27 >
28
29 The original post says what's wrong with ar. Please be more specific if
30 you disagree with it.
31
32 --
33 Best regards,
34 Michał Górny

Attachments

File name MIME type
signature.asc application/pgp-signature

Replies

Subject Author
Re: [gentoo-portage-dev] Re: [RFC] gpkg format proposal v2 Ulrich Mueller <ulm@g.o>