Something is wrong if your mail client is using 13.0GB of memory

On my fairly new quad-core 4GB RAM system I noticed that suddenly closing tabs in the web browser resulted in tons of disk accesses, which I [correctly] attributed to swap usage. This is quite a big surprise, since I don't use any integrated desktop and generally only run lots of uxterms in ion3 (over two 1600x1200 heads with 8 virtual desktops on each head) plus firefox.

As it turns out, earlier today I started thunderbird (Debian calls it icedove) in order to do some cleanup (moving folders around) on my IMAP server. After about half a day, I was looking at the following line in top:

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                               
 3474 laforge   20   0 13.1g 3.1g  10m D    1 81.7  47:49.91 icedove-bin                                                            
This is ridiculous. 13GB virtual, 3.1GB resident set size. And all that with something like roughly 3 million e-mails spread over about 200 IMAP folders.

Who is supposed to use those programs? What do they use for testing? People with 10 mails in their inbox? Also, if you actually download the headers of a new folder, or headers of new mails in a folder, it takes _ages_. It looks actually like they individually request the headers of each email, without using the tagged command features of IMAP, thereby removing all the pipelining effects and being bound to one complete thunderbird-through-kernel-through-network-through-imap-server roundtrip per message. I haven't actually looked at the code, but just from observing the application, this seems to be the case. Also, every time I use the 'search messages' feature for any header that the IMAP server does not have an index for, thunderbird refuses to wait long enough until the server responds.

So far I always thought mutt's memory usage of 40-80MB is already excessive, considering all it does is displaying a bit of plain-text emails. Well, for once I've been happy again that I'm not a regular user of those kind of bloated GUI programs. firefox somehow being the sole exception to that. It's barely useable on my 1.06GHz / 512MB laptop, where you already notice quite considerable lag in the responsiveness of the UI. :/

Guess next time I have to move folders, I'll probably revert to something like cyradm (that's a minimalistic imap client with command shell, not unlike the old 'ftp' command for FTP).