Re: [Monotone-devel] Re: results of mercurial user survey

[Johan Bolmsjö]

On Sunday 30 April 2006 15:54, Lapo Luchini wrote:
> Richard Levitte - VMS Whacker <richard <at> levitte.org> writes:
> > On the plus side, this also means that we could leave it to the user
> > to decide if and how strong compression xe wants.  This means, of
> > course, the the peers in a netsync communication will have to do a bit
> > of negitiation at the beginning, but the cost for that should be very
> > small.
> >
> > Another plus side, should the .ssh branch ever start being used, is
> > that we can leave it up to the ssh protocol to do the compression part
> > for us.
>
> Usually the higher the level you compress at, the better compression you
> get, since there is more repetitions to be found (e.g. in the "headers" of
> the lower-level packets, data repeated in different packets...) and
> dictionary is resetted less often and so on.
>
> IMHO the data stream should contain uncompressed data and be compressed at
> the stream level.
>
> BTW: what about bzip2?
>
>     Lapo
>

bzip is much slower than gzip. If you want somewhat improved compression speed 
you could use the lzo library instead of gzip. Here are some benchmarks using 
the command line utilities.

johan.db is the original file that is compressed by all utils. I guess that 
the data I compressed is not the best (already compressed?) monotone db.

address@hidden:~/.monotone$ time gzip johan.db.1
real    0m0.951s
user    0m0.949s
sys     0m0.000s

address@hidden:~/.monotone$ time gzip -3 johan.db.2
real    0m0.824s
user    0m0.803s
sys     0m0.020s

address@hidden:~/.monotone$ time bzip2 johan.db.3
real    0m3.632s
user    0m3.614s
sys     0m0.014s

address@hidden:~/.monotone$ time lzop johan.db.4
real    0m0.347s
user    0m0.308s
sys     0m0.037s

address@hidden:~/.monotone$ ls -l johan.db*
-rw-------  1 johan  johan  9633792 Apr  2 23:54 johan.db
-rw-------  1 johan  johan  6597871 Apr 30 19:08 johan.db.1.gz
-rw-------  1 johan  johan  6741666 Apr 30 19:08 johan.db.2.gz
-rw-------  1 johan  johan  6588439 Apr 30 19:08 johan.db.3.bz2
-rw-------  1 johan  johan  8662181 Apr 30 19:10 johan.db.4.lzo