Understanding Dirty Read and Non-Repeatable Phenomena in Postgres: A Visual Demo

In this video, you'll see a demonstration of dirty read and non-repeatable phenomena in Postgres at Read Committed isolation level.

Dirty read is blocked:

• The first transaction issues an update statement but not committed yet.
• The second transaction should not read uncommitted changes made by the first one.

Non-repeated read is active:

• The first transaction: read the same row twice
• The second transaction: update this row between these 2 reads -> the first transactions gets different results each time.