x => r2017.11.06-insert-throughput.log 
y => 9acbd68815499fc7f8fbb5931d643b8fd7804a80-insert-throughput.log 

     n min   max  median  average   stddev      p99
x 3600   0 21318 18488.0 15797.58 5741.996 20830.04
y 3600   0 21368 18378.5 15700.26 5727.454 20844.00

000                  10000                 15000                 20000          
 |---------------------+---------------------+---------------------+-----------|
                                          +-----------------+---+               
1        ---------------------------------|                 |   |---------      
                                          +-----------------+---+               
                                         +------------------+---+               
2    ------------------------------------|                  |   |---------      
                                         +------------------+---+               
Legend: 1=data$x, 2=data$y

At 95% probablitiy:
===> average not statistically significant    (p=0.471564, diff ~97.318056)
===> variance not statistically significant   (p=0.879094)