Write Skew anomaly in Oracle and PostgreSQL does not rollback transaction

Question

I noticed the following occurrence in both Oracle and PostgreSQL.

Considering we have the following database schema:

create table post (
    id int8 not          


        

Answer 1

The Postgres documentation defines a phantom read as:

A transaction re-executes a query returning a set of rows that satisfy a search condition and finds that the set of rows satisfying the condition has changed due to another recently-committed transaction.

Because your select returns the same value both before and after the other transaction committed, it does not meet the criteria for a phantom read.