In this benchmark, a small database is generated, and each test is executed 20 times under the following conditions:

==================== ==================================================
CPU                  Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
RAM                  24634516 kB
Disk                 SAMSUNG MZVPW256HEGL-00000
Linux distribution   Ubuntu 18.04 bionic
Python               3.7.0b3
Django               2.1
cachalot             2.1.0
sqlite               3.22.0
PostgreSQL           10.4
MySQL                5.7.23
Redis                4.0.9
memcached            1.5.6
psycopg2             2.7.5
mysqlclient          1.3.13
==================== ==================================================
