MySQL itself is not based on BerkeleyDB, but to allow for
transactions support, BerkeleyDB and
InnoDB table types were added during the 3.23.x series.
Some speed propaganda on MySQL can be found on their
benchmarking page
DISCLAIMER: I am not advocating MySQL as a solution
to this particular problem. I am only attempting to dispel
the myth that MySQL is itself based on BerkeleyDB.