Benchmark: timing 500 iterations of CSV_Update, Flatfile_Update, Mysql_Update...
CSV_Update: 17312 wallclock secs (16920.40 usr + 135.93 sys = 17056.33 CPU) @  0.03/s (n=500)
Flatfile_Update: 244 wallclock secs (207.73 usr + 31.91 sys = 239.64 CPU) @  2.09/s (n=500)
Mysql_Update: 263 wallclock secs ( 8.27 usr +  2.63 sys = 10.90 CPU) @ 45.87/s (n=500)