Back-End Development Back-End Performance and Caching 3

Question 1

What is profiling in back-end performance optimization?

Accepted Answer

Measuring the runtime behavior of code to identify bottlenecks in CPU usage, memory consumption, and execution time

Answer

Creating user profiles in the application database

Answer

Writing performance requirements in a specification document

Answer

Configuring server hardware for optimal performance

Question 2

What is the purpose of database read replicas in a high-traffic back-end system?

Accepted Answer

To offload read queries to replica servers, reducing load on the primary write database and improving read throughput

Answer

To backup the primary database automatically

Answer

To improve write performance by distributing insert operations

Answer

To provide a testing environment that mirrors production

Question 3

What is connection timeout and why should it be set in back-end applications?

Accepted Answer

The maximum time to wait for a database or external service connection before giving up and returning an error

Answer

The time a user session remains active before logout

Answer

The interval between health check pings

Answer

The duration a cached database connection remains open

Question 4

What is a cold start in serverless back-end functions?

Accepted Answer

The latency incurred when a serverless function is invoked after being idle, requiring the provider to initialize the execution environment

Answer

Starting a new database from scratch with no data

Answer

Deploying a new version of a function without downtime

Answer

The first API call after a server restarts

Question 5

What does the term 'throughput' mean when measuring back-end performance?

Accepted Answer

The number of requests or transactions a system can process per unit of time

Answer

The time taken to process a single request from end to end

Answer

The maximum number of concurrent database connections

Answer

The total amount of data stored in the database

Question 6

What is the difference between latency and response time in back-end performance?

Accepted Answer

Latency is the network delay portion; response time is the total time from request sent to response received (latency + processing time)

Answer

They are interchangeable terms with no meaningful distinction

Answer

Latency refers to server processing time; response time refers to network delay only

Answer

Latency is measured in MB/s; response time is measured in milliseconds