dpkg-lzma
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Size: 2340
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| Include: * data migration, if any * redirects from old URLs to new ones, if any * how users will be pointed to the new way of doing things, if necessary. |
To support migrating to using lzma compression dpkg should depends on lzma and packages that use lzma compression should pre-depends on that version of dpkg or newer. |
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It's important that we are able to test new features, and demonstrate them to users. Use this section to describe a short plan that anybody can follow that demonstrates the feature is working. This can then be used during CD testing, and to show off after release. This need not be added or completed until the specification is nearing beta. |
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| This should highlight any issues that should be addressed in further specifications, and not problems with the specification itself; since any specification with problems cannot be approved. apt doesn't fully support lzma yet. In particular apt-ftparchive contents did not work. I have included a patch that supports lzma except for one function in apt-pkg/acquire-item.cc 'pkgAcqIndex::Failed' that someone more familiar with apt should look over. |
apt doesn't fully support lzma yet. However, this doesn't appear to affect package upgrades. In particular apt-ftparchive contents did not work. I have included a patch that supports lzma except for one function in apt-pkg/acquire-item.cc 'pkgAcqIndex::Failed' that someone more familiar with apt should look over. |
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| Use this section to take notes during the BoF; if you keep it in the approved spec, use it for summarising what was discussed and note any options that were rejected. | Some packages may not be able to be compressed using lzma due to installation bootstrapping issues. |
Code changes should include an overview of what needs to change, and in some cases even the specific details.
Migration
To support migrating to using lzma compression dpkg should depends on lzma and packages that use lzma compression should pre-depends on that version of dpkg or newer.
Test/Demo Plan
The following packages need to have lzma support and currently have it:
- dpkg
- installing - 1.13.25 (Tue, 2 Jan 2007 00:23:57 +0200)
- creating - 1.14.0 (Tue, 08 May 2007 11:11:50 +0300)
- apt - 0.7.5 (Wed, 25 Jul 2007 20:16:46 -0300)
To build packages, when using debhelper, using lzma compression you need to use: dh_builddeb -- -Zlzma
Example: openoffice.org-core
type |
size |
c time |
c memory |
d time |
d memory |
gzip |
38,941,278 |
26s |
1M |
1.0s |
1M |
bzip2 |
37,319,546 |
24s |
8M |
7.5s |
4M |
lzma |
27,002,374 |
107s |
370M |
3.3s |
34M |
If we were to convert the entire Ubuntu 7.10 alternate cd to each of the following formats it would be the following sizes:
original |
none |
gzip |
bzip2 |
lzma |
675,113,008 |
1,816,544,474 |
708,735,160 |
643,077,920 |
501,460,266 |
The following ODS file has a comparison of the sizes of all packages on the Ubuntu 7.10 Alternate CD compressed with gzip, bzip2, lzma compared to what is currently in the archive:
attachment:ubuntu-alternate-cd-lzma.ods
We could also save bandwidth by creating Packages files using lzma compression.
Packages files:
|
none |
gzip |
bzip2 |
lzma |
main |
6677465 |
1417147 |
1090948 |
1022666 |
restricted |
25680 |
6937 |
6731 |
6419 |
universe |
20146818 |
5538514 |
4236954 |
3803292 |
multiverse |
692816 |
199044 |
153630 |
156726 |
Outstanding Issues
apt doesn't fully support lzma yet. However, this doesn't appear to affect package upgrades. In particular apt-ftparchive contents did not work. I have included a patch that supports lzma except for one function in apt-pkg/acquire-item.cc 'pkgAcqIndex::Failed' that someone more familiar with apt should look over.
attachment:apt_0.7.9-lzma.diff
BoF agenda and discussion
Some packages may not be able to be compressed using lzma due to installation bootstrapping issues.
dpkg-lzma (last edited 2009-03-21 12:57:20 by 75-165-16-192)