Microservices Data Management Strategies 3

Question 1

What is the primary purpose of the CQRS pattern in microservices?

Accepted Answer

Separating read and write models for independent optimization

Answer

CQRS (Command Query Responsibility Segregation) splits read and write models so each can scale and be optimized separately.

Question 2

In Event Sourcing, how is the current state of an entity derived?

Accepted Answer

By replaying the sequence of stored events

Answer

Event Sourcing stores state changes as a log of events; current state is reconstructed by replaying them.

Question 3

Which problem does the Transactional Outbox pattern solve?

Accepted Answer

Reliably publishing events as part of a local database transaction

Answer

The Outbox pattern writes events to an outbox table in the same transaction as the data change, then publishes them reliably.

Question 4

What is the 'dual-write problem' in microservices data management?

Accepted Answer

The risk of inconsistency when writing to a database and a message broker separately

Answer

Dual writes can fail partway, leaving the database and message broker out of sync without an atomic mechanism.

Question 5

Which technique reads a database's transaction log to capture and stream data changes?

Accepted Answer

Change Data Capture (CDC)

Answer

CDC tools like Debezium tail the transaction log to emit change events to other services.

Microservices Practice Test