I have taken this in to serious consideration, however the impact of this does not justify it.
in reply to Re: Finding an intersection of two sets, lean and mean
in thread Finding an intersection of two sets, lean and mean
The problem with huge and fast is not disk space, it's memory space. The software that performs the mailings all runs daemonized, since start-up is our biggest penalty, having 5 500M(++) daemons laying around is not funny.
I need to preserve RAM space (eg: pref. no more then the size of the file) and be fast with my blacklisting, since operators are getting more and more demanding.
Dragonchild's solution was my first attempt as well, it consumes less memory but it is slow(er) so I came up with the above piece of code... TIMTOWTDI, remember?