Copied from debian:540626 :

Experimental evidence suggests that HEAD requests will result in
Roundup generating the entire page, discard it, then send the headers
to the client.  This is very wasteful, particularly on large pages.

Making requests to bugs.darcs.net *from* bugs.darcs.net (to avoid
network latency), we can see that HEAD and GET take about the same
amount of time:

    $ time nc bugs.darcs.net www <<<$'HEAD /status1 HTTP/1.1\nHost:
bugs.darcs.net\n\n' | wc -l
    7

    real    0m18.549s
    user    0m0.004s
    sys     0m0.004s
    $ time nc bugs.darcs.net www <<<$'GET /status1 HTTP/1.1\nHost:
bugs.darcs.net\n\n' | wc -l
    3117

    real    0m18.324s
    user    0m0.004s
    sys     0m0.004s

This issue has practical implications for me.  I maintain a script to
interact with roundup's mailgw, and I wanted to valid status IDs
before sending emails:

    if ! curl -fsIo/dev/null http://bugs.example.net/status$N
    then error "$N is not a valid status ID!"
    fi

Currently this request can take deciseconds, and so is far too slow to
use.




I've talked to both Eric Kow of darcs.net to get 1.4.13 installed there,
and to the user, who has confirmed that the problem is still present in
the latest version of roundup.