#428: cabal update uses too much bandwidth ---------------------------------+------------------------------------------ Reporter: claus | Owner: Type: defect | Status: new Priority: normal | Milestone: cabal-install-0.8 Component: cabal-install tool | Version: 1.6.0.1 Severity: normal | Resolution: Keywords: | Difficulty: hard (< 1 day) Ghcversion: 6.8.3 | Platform: ---------------------------------+------------------------------------------ Comment (by igloo): FWIW, what Debian/apt does is, when making a new package list: * Run `diff -e` (Output an ed script) between the last package list and the new one * Add a line with the hash of the last package list, and the script filename to the index * Garbage collect old lines from the index as appropriate (e.g. leave at most n lines in the remove entries more than d days old, etc. In Debian it's easier as the package list is updated exactly once a day), along with the scripts that those lines point to. Then to update the index you: * Download the index * If the hash of your package list is in the index, download and apply all scripts since then * Otherwise, download the whole new package list Example index is http://ftp.uk.debian.org/debian/dists/unstable/main/binary-i386/Packages.dif... with scripts in the http://ftp.uk.debian.org/debian/dists/unstable/main/binary-i386/Packages.dif... directory. To do this for hackage, cabal-install would need to be able to apply ed scripts itself - or at least, enough of it that it can apply scripts that `diff -e` makes. -- Ticket URL: http://hackage.haskell.org/trac/hackage/ticket/428#comment:5 Hackage http://haskell.org/cabal/ Hackage: Cabal and related projects