Pitfalls of Isolation Levels in Distributed Databases Posted by sougou on Wednesday October 14, 2020 @03:46PM from the planetscale.com dept. https://www.planetscale.com/blog/pitfalls-of-isolation-levels-in-distributed-databases ( 1 comment | 2 points | on HN )
https://www.postgresql.org/docs/9.5/transaction-iso.html
and can be done w/o any locking or waiting -- you can keep track of which data transaction A has accessed and if transaction B commits that changes something A depends on you abort transaction A and the application can try it over.