Pacman will download the db on every -Syu.

It seems that pacman isn't looking at the second header which contains
the necessary Last-Modified data. The example is a weird redirect, so
I don't know if this is a valid bug. I'll let the smart people decide.

Here's output from wget to show the problem:

[louipc@lynn pacman]$ wget -S http://xyne.archlinux.ca/repos/any/xyne-any.db.tar.gz
--2010-06-04 20:19:00-- http://xyne.archlinux.ca/repos/any/xyne-any.db.tar.gz
Resolving xyne.archlinux.ca... 69.89.25.172
Connecting to xyne.archlinux.ca|69.89.25.172|:80... connected.
HTTP request sent, awaiting response...
HTTP/1.1 301 Moved Permanently
Date: Sat, 05 Jun 2010 00:17:43 GMT
Server: Apache/2.2.15 (CentOS) mod_ssl/2.2.15 0.9.8l DAV/2 mod_auth_passthrough/2.1 FrontPage/5.0.2.2635
Location: http://xyne.archlinux.ca/repos/xyne-any/xyne-any.db.tar.gz
Keep-Alive: timeout=10, max=30
Connection: Keep-Alive
Content-Type: text/html; charset=iso-8859-1
Location: http://xyne.archlinux.ca/repos/xyne-any/xyne-any.db.tar.gz [following]
--2010-06-04 20:19:00-- http://xyne.archlinux.ca/repos/xyne-any/xyne-any.db.tar.gz
Connecting to xyne.archlinux.ca|69.89.25.172|:80... connected.
HTTP request sent, awaiting response...
HTTP/1.1 200 OK
Date: Sat, 05 Jun 2010 00:17:43 GMT
Server: Apache/2.2.15 (CentOS) mod_ssl/2.2.15 0.9.8l DAV/2 mod_auth_passthrough/2.1 FrontPage/5.0.2.2635
Last-Modified: Sun, 23 May 2010 17:02:59 GMT
ETag: "a4d0021-1910-48745e57536c0"
Accept-Ranges: bytes
Content-Length: 6416
Keep-Alive: timeout=10, max=30
Connection: Keep-Alive
Content-Type: application/x-gzip
Length: 6416 (6.3K) [application/x-gzip]
Server file no newer than local file “xyne-any.db.tar.gz” -- not retrieving.