PostgreSQL 15 is used in this demo.
Tests that show the different outcomes are in TransactionIsolationDemoApplicationTests.java
according to PostgreSQL doc
| Isolation Level | Dirty Read | Nonrepeatable Read | Phantom Read | Serialization Anomaly |
|---|---|---|---|---|
| Read uncommitted | Allowed, but not in PG | Possible | Possible | Possible |
| Read committed | Not possible | Possible | Possible | Possible |
| Repeatable read | Not possible | Not possible | Allowed, but not in PG | Possible |
| Serializable | Not possible | Not possible | Not possible | Not possible |