Anwsering my own comment cause I can't edit it anymore, but this article has started a heated debate on tweeter. The author of "black" suggested that the cause

Anwsering my own comment cause I can't edit it anymore, but this article has started a heated debate on tweeter. The author of "black" suggested that the cause of the slow down may be that asyncio actually starved postgres for resources: https://twitter.com/llanga/status/1271719783080366086 https://twitter.com/llanga/status/1271719783080366086