Data consistency challenges in Microservices - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is data consistency in the context of microservices?

Data consistency means that all microservices have the same, up-to-date information at the same time, so users see correct and reliable data everywhere.

intermediate

Why is maintaining strong consistency difficult in microservices?

Because microservices are separate and communicate over networks, delays and failures can cause data to be out of sync temporarily, making strong consistency hard to guarantee.

beginner

What is eventual consistency?

Eventual consistency means data will become consistent across services after some time, even if it is temporarily different during updates.

intermediate

Name one common pattern to handle data consistency in microservices.

The Saga pattern helps manage distributed transactions by breaking them into smaller steps with compensations to keep data consistent.

advanced

What problem does the two-phase commit protocol solve, and why is it less used in microservices?

It solves atomic transactions across services but is less used because it can cause delays and reduce system availability due to locking resources.

Which consistency model allows temporary data differences but guarantees eventual synchronization?

A Strong consistency

B Immediate consistency

C Eventual consistency

D No consistency

Eventual consistency means data will sync over time, allowing temporary differences.

What is a main challenge of using two-phase commit in microservices?

A It can cause system delays and reduce availability

B It does not guarantee data consistency

C It is easy to implement

D It only works for single databases

Two-phase commit locks resources and can delay the system, reducing availability.

Which pattern helps manage distributed transactions by breaking them into smaller steps with compensations?

A Observer pattern

B Singleton pattern

C Factory pattern

D Saga pattern

Saga pattern manages distributed transactions with steps and compensations.

Why do microservices often face data consistency challenges?

A Because they use the same database

B Because they are distributed and communicate over unreliable networks

C Because they never update data

D Because they run on a single server

Distributed nature and network delays cause consistency challenges.

Which consistency model requires all services to see the same data instantly?

A Strong consistency

B Eventual consistency

C Weak consistency

D No consistency

Strong consistency means all see the same data immediately.

Explain the main data consistency challenges in microservices and how they differ from monolithic systems.

Think about how separate services communicate and update data.

Describe the Saga pattern and how it helps maintain data consistency in microservices.

Imagine a multi-step process that can be reversed if something fails.