[Dovecot] v1.2 development tree started

Ed W lists at wildgooses.com
Fri Jun 20 15:02:11 EEST 2008

Timo Sirainen wrote:
> This one is the last major unimplemented v1.2 feature.

Can I make a very weak suggestion to look at that ZLIB compression 
extension I think you mentioned in the past?

The motivation is that I find my "8 mbit broadband" link seems to 
saturate at quite low numbers of headers per second when Thunderbird is 
pulling down new mailbox messages.  As you know on most of my machines I 
use our compression proxy application which is very noticably increasing 
my mailbox access speeds even on cutting edge broadband (for europe).

Now whilst probably zero clients implement the compression extension 
this is also a chicken/egg thing so we could start by having a working 
implementation on the server end at least

Second reason is that this suggests that a typical rented server with a 
meagre 100mbit connection could be network limited while replicating, 
rather than being network or CPU bound.  A lightly compressed protocol 
*might* be a win even on fairly fast connections simply because many of 
the imap command outputs seem to compress extremely well (13:1 is 
typical based on the rather inefficient way OE accesses IMAP and 4:1 
average is very normal even for more efficient implementations - YMMV)

Anyway, just a thought - I'm assuming that the probable implementation 
is going to be fairly simple.  I would think that zlib and/or lzo would 
be good compressors if there is a choice of implementations?  Certainly 
LZO would be a good choice for faster 100mbit connections

Ed W

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