试了。瓶颈在磁盘的情况下，用并行 copy 或者 直接 copy 时间差别不大。
at 30s, row rate 666546.92/sec (period), row rate 666546.92/sec (overall), 2.000000E+07 total rows
at 1m0s, row rate 653333.72/sec (period), row rate 659940.91/sec (overall), 3.960000E+07 total rows
at 1m30s, row rate 530000.43/sec (period), row rate 616630.03/sec (overall), 5.550000E+07 total rows
at 2m0s, row rate 546666.11/sec (period), row rate 599139.82/sec (overall), 7.190000E+07 total rows
at 2m30s, row rate 546659.98/sec (period), row rate 588644.12/sec (overall), 8.830000E+07 total rows
at 3m0s, row rate 530004.70/sec (period), row rate 578871.27/sec (overall), 1.042000E+08 total rows
at 3m30s, row rate 543335.38/sec (period), row rate 573794.86/sec (overall), 1.205000E+08 total rows
at 4m0s, row rate 523331.66/sec (period), row rate 567487.09/sec (overall), 1.362000E+08 total rows
4 分钟插入了一亿多条数据，13 亿差不多也得 40 分钟左右。
但是，关闭日志(建表时 unlogged), 速度提升很大：
at 30s, row rate 1826650.79/sec (period), row rate 1826650.79/sec (overall), 5.480000E+07 total rows
at 1m0s, row rate 2005766.79/sec (period), row rate 1916228.49/sec (overall), 1.150000E+08 total rows
at 1m30s, row rate 1990897.15/sec (period), row rate 1941106.77/sec (overall), 1.747000E+08 total rows
一亿多条数据，只需要 1 分钟左右。
综合看，如果用 HDD，瓶颈大概率在硬盘这里，关闭日志可以提升写性能。原推可能用了比较慢的硬盘。
回头有空，找一台 SSD 的物理服务器测试下。
