crcastleAWS engineer reports PostgreSQL perf halved by Linux 7.0, fix may not be easy
https://lore.kernel.org/lkml/yr3inlzesdb45n6i6lpbimwr7b25kqk...
Its worth reading this follow-up LKML post by Andres Freund (who works on Postgres): https://lore.kernel.org/lkml/yr3inlzesdb45n6i6lpbimwr7b25kqk...
Note that it's just not a single post, and there's additional further information in following the full thread. :)