Martín Marqués <martin@bugs.unl.edu.ar> writes:
> P.D.: bzip2 is slow, but you can get a real small package with it, even
> though PostgreSQL isn't that big, if we compare it with KDE or Mozilla.
As an experiment, I zipped my current PG source tree with both. (This
isn't an exact test of the distribution size, because I didn't bother
to get rid of the CVS control files, but it's pretty close.)
Original tar file: 37089280 bytes
gzip -9: 8183182 bytes
bzip2: 6762638 bytes
or slightly less than a 20% savings for bzip over gzip. That's useful,
but not exactly compelling. A comparison of unzip runtime also seems
relevant:
$ time gunzip pgsql.tar.gz
real 0m5.48s
user 0m4.46s
sys 0m0.62s
$ time bunzip2 pgsql.tar.bz2
real 0m27.77s
user 0m26.50s
sys 0m0.92s
If I'd downloaded this thing over a decent DSL or cable modem line,
bzip2 would actually be a net loss in total download + uncompress time.
<editorial>
The reason bzip is still an also-ran is that it's not enough better
than gzip to have persuaded people to switch over. My bet is that
bzip will always be an also-ran, and that gzip will remain the de
facto standard until something comes along that's really significantly
better, like a factor of 2 better. I've watched this sort of game
play out before, and I know you don't take over the world with a 20%
improvement over the existing standard. At least not without other
compelling reasons, like speed (oops) or patent freedom (no win there
either).
</editorial>
regards, tom lane
