C100DBA Application Administration Practice Question
When designing an application, what is the best practice for handling connection pools?
⚠ Common exam trap
Candidates often suggest creating a new connection for every request to ensure freshness. This ignores the massive performance overhead of repeated TCP handshakes and authentication on the database server.
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
✓
Maintain a long-lived, singleton instance of the MongoClient.
Maintaining a single, long-lived connection pool instance in the application is the most efficient way to manage database connections. Repeatedly creating and destroying connections is extremely expensive, introducing unnecessary latency and resource overhead on both the application server and the database. Proper pool management is a core application administration task that ensures the database handles traffic gracefully without exhausting its maximum configured connection limit due to unnecessary connection churn from the client side.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Create a new connection for every query.
Why it's wrong here
Creating a new connection for every query introduces significant overhead due to the TCP handshake and authentication process. This practice quickly depletes available database file descriptors and memory, leading to performance degradation and potentially causing the database to reject new connections during periods of high application demand.
- ✓
Maintain a long-lived, singleton instance of the MongoClient.
Why this is correct
A single MongoClient instance in an application acts as a connection pool. Sharing this instance across the application enables efficient reuse of existing connections, which reduces latency and database load. This is the recommended practice for all production applications to ensure stability and high performance when interacting with MongoDB.
- ✗
Close the connection after every single write operation.
Why it's wrong here
Closing connections after every write is inefficient and unnecessary. Modern drivers are designed to keep connections open to facilitate rapid communication. Frequently opening and closing connections increases latency and prevents the driver from efficiently managing the state and authorization of the connection session to the MongoDB server.
- ✗
Set the connection pool size to zero.
Why it's wrong here
A connection pool size of zero would prevent the application from maintaining any connections to the database, effectively disabling communication. The driver needs a pool to function, and setting it to zero contradicts the requirement for the application to interact with the database store in a standard, performant manner.
About these practice questions
This C100DBA question is part of Courseiva's 222-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam 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.