query_dbh: 24 wallclock secs ( 5.28 usr +  5.29 sys = 10.57 CPU) @ 3784.30/s (n=40000)
 query_mem: 70 wallclock secs ( 7.80 usr +  6.08 sys = 13.88 CPU) @ 2881.84/s (n=40000)