[pacman-dev] Incremental package index support?

[Anatol Pomozov]

Hi,

I am an update junkie. I do "pacman -Suy" several times a day. One
thing I do not like with current pacman is that it redownloads whole
index file each time I update system.

:: Synchronizing package databases...
 core                     104.4 KiB   104K/s 00:01 [######################] 100%
 extra                   1416.9 KiB   171K/s 00:08 [######################] 100%
 community               1916.6 KiB   204K/s 00:09 [######################] 100%

It is 3.5M it total even if only just a few new packages were added.
Multiply 3.5M to number of users and you'll get a huge number. IMHO it
is waste of bandwidth and user time. From other side index is
incremental by it nature. Could pacman use index format that fits
incremental updates better?

A naive proposal is to use compressed format for "full fetch" (e.g.
for users who did not update more than a week), and uncompressed
append-only index for incremental. On incremental update client sends
request to server "give me append file file starting from position XXX
till the end of file", so only delta from the last update will be
fetched. Then pacman applies the delta to client index.

What do you think about this idea?