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• Launchpad Entry: foundations-karmic-pre-unpacking

• Created:

• Contributors:

• Packages affected: apt, dpkg

Summary

Discussion of installing packages DURING the download of multiple packages, versus AFTER the download of all packages completes.

Release Note

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It is mandatory.

Rationale

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User stories

Assumptions

Design

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Implementation

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UI Changes

Should cover changes required to the UI, or specific UI that is required to implement this

Code Changes

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Migration

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• 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.

Test/Demo Plan

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This need not be added or completed until the specification is nearing beta.

Unresolved issues

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.

BoF agenda and discussion

notes:mvo

unpack while downloading

currently: - download all - install all (serialized)

- use bootchart to profile the package install time

Optimization ideas: - run dpkg --unpack to a different place while downloading - *but* preinst is also run - needs to be on the same filesystem

- would have to parition the download into self-contained

• groups

- big groups of pkgs are good (because dpkg database handling

• is slow)

- next steps:

• - benchmark to figure out what really takes the time
  • - could be maintainer scripts - could be unpack - could be configure
  - so figure out how much time saving we get

- marks "cache" idea:

• - download package - when package downloaded (pre)unpack it into a "cache" area
  • (that can well be just the regular name/destination that dpkg
    • uses anyway)
  - when finished all downloads, run dpkg normally - if anything fails blow away the cache - problem with this idea: needs a lot of diskspace Cache design: - add indexfile to /var/lib/dpkg/... that records what dpkg
  • has done in order to cleanly rollback
  - new pre-unpacked, half-pre-unpacked, etc in the status file Cache design(2): - mark the pre-unpacked with a different filename (foo.preunpack.dpkg-tmp)
  • or (foo.preunpacked.$sha1.dpkg-tmp) to make cleanup easier
  Cache design(3): - unpack into a seperate dir

Simple idea: - what about data.tar.gz unpacking in /var/cache/apt/archives

• when a download is finished (profile this!)

future idea (tricky): - split it up into paritions - when a download set is finished, keep downloading - install packages when a set is self-contained (while still downloading) - problems: debconf --preconfigure (that is optional but results in

• questions during the install)

- progress bar when a package is asking questions

problems with the idea: - apt-listchanges - error handling - selinux labeling handling

CategorySpec