Richard Jelinek, 28/01/2012 00:38:
don't know if this issue came up already - in case it did and has been dismissed, I beg your pardon. In case it didn't...
There's a quite old comparison here: https://www.mediawiki.org/wiki/Dbzip2 but https://wikitech.wikimedia.org/view/Dumps/Parallelization suggests it's still relevant.
Nemo