21:49:26.171 UTC [44861] ubuntu@myapp LOG:  duration: 3063.262 ms  statement: COMMIT
21:49:26.171 UTC [44890] ubuntu@myapp LOG:  duration: 748.307 ms  statement: COMMIT
21:49:26.171 UTC [44882] ubuntu@myapp LOG:  duration: 1497.461 ms  statement: COMMIT
21:49:26.171 UTC [44893] ubuntu@myapp LOG:  duration: 655.063 ms  statement: COMMIT
21:49:26.171 UTC [44894] ubuntu@myapp LOG:  duration: 559.743 ms  statement: COMMIT
21:49:26.172 UTC [44883] ubuntu@myapp LOG:  duration: 1415.733 ms  statement: COMMIT

AWS EC2 m4.4xlarge (16 cores, 64GB RAM)
Elastic Block Store gp2 volumes (105 IOPS, burst upto 3000 IOPS)

10/15/2017 08:28:35 PM
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
          10.44    0.00    0.93    0.15    0.06   88.43

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     0.00    0.00    2.00     0.00     0.04    38.67     0.00    0.00    0.00    0.00   0.00   0.00
xvdb              0.00     2.67    0.00   44.67     0.00     0.41    18.99     0.13    2.81    0.00    2.81   1.07   4.80

10/15/2017 10:18:11 PM

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           8.16    0.00    0.65   11.90    0.04   79.24

Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     4.00    0.00    1.00     0.00     0.02    48.00     0.00    1.33    0.00    1.33   1.33   0.13
xvdb              0.00     0.00    1.67 1312.00     0.01   163.50   254.90   142.56  107.64   25.60  107.75   0.76 100.00

shared_buffers = 2GB
checkpoint_timeout = 30min              # range 30s-1d
max_wal_size = 2GB
min_wal_size = 700MB
checkpoint_completion_target = 0.9      # checkpoint target duration, 0.0 - 1.0
#checkpoint_flush_after = 256kB         # measured in pages, 0 disables
#checkpoint_warning = 30s               # 0 disables