MySQL.
[9]: insert_people(15, 500) Elapsed 1.63 seconds Rows per second: 4606.10 In [10]: insert_people(20, 500) Elapsed 1.98 seconds Rows per second: 5055.93 In [11]: insert_people(25, 500) Elapsed 2.42 seconds Rows per second: 5160.38 In [12]: insert_people(30, 500) Elapsed 2.77 seconds Rows per second: