Unfortunately that benchmark was very inaccurate. They tuned the postgres configuration and didn't tune MongoDB. They also used an unsupported, experimental driver without connection pooling on MongoDB.

For example: they measured Query B execution time on postgres: 41m3s, mongodb: 1h13m3s. When MongoDB measured Query B with a supported driver, the execution time was only 3m30s more than 10x faster than postgres!

You'll find details here: https://www.mongodb.com/blog/post/benchmarking-do-it-right-o...