Q12. What is PostgreSQL's default isolation level?
READ COMMITTED is the default. Each statement sees a snapshot as of the statement start. Stronger isolation levels can require transaction retries.
Interview tip: explain the core behavior, then mention one operational trade-off or edge case.
Note
Interview approach: define the concept, explain when you use it, and mention one limitation or production consideration.
Concept example
-- Demonstrate the concept with a small query or schema example
SELECT current_database();💡 This short query illustrates the PostgreSQL environment used during examples. In an interview, adapt the example to the specific concept and explain the underlying behavior.
Key Takeaways
- Give a concise definition.
- Explain a real-world use case.
- Mention one trade-off or safety consideration.
Knowledge Check
What is the default isolation level?