C100DBA Philosophy and Features Practice Question
A development team is building a real-time analytics dashboard that reads from a MongoDB replica set. The dashboard can tolerate slightly stale data but must never show data that could be rolled back. The team also wants to minimize read latency. Which read concern should they use?
⚠ Common exam trap
The trap here is thinking that local read concern is acceptable because the dashboard tolerates stale data, but local does not protect against rollback of uncommitted writes.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
read concern majority
Read concern majority guarantees that the data returned has been acknowledged by a majority of replica set members and is rollback-safe, while still allowing reads from secondaries to reduce latency. Since the dashboard tolerates slight staleness, this is the ideal balance between consistency and performance.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
read concern majority
Why this is correct
Read concern majority returns data that has been acknowledged by a majority of replica set members and is therefore durable and cannot be rolled back. It may return slightly stale data, but the dashboard tolerates staleness. It also allows reads from secondaries, which can reduce latency by distributing read load. This is the best fit for the stated requirements.
- ✗
read concern linearizable
Why it's wrong here
Linearizable read concern provides the strongest consistency guarantee: reads reflect all successful writes that completed before the read. However, it requires reading from the primary and can block if a majority of members are unavailable, increasing latency. Since the dashboard tolerates stale data, linearizable is unnecessarily strict and would not minimize latency.
- ✗
read concern snapshot
Why it's wrong here
Read concern snapshot is used within multi-document transactions to provide a consistent snapshot of data across multiple documents. It is not intended for general dashboard queries outside a transaction. Using it outside a transaction is not supported. It also does not address the requirement for rollback-safe reads in a simple read scenario.
- ✗
read concern local
Why it's wrong here
Read concern local returns data from the queried instance without guaranteeing that it has been majority-committed. If the primary fails before replicating, the returned data could roll back. While local offers the lowest latency, it violates the requirement that the dashboard must never show data that could be rolled back. The stale tolerance does not extend to rollback risk.
About these practice questions
Courseiva writes every C100DBA question from scratch — 222 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official MongoDB exam blueprint
This C100DBA practice question is part of Courseiva's free MongoDB certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the C100DBA exam.