What is Redis - Practice Questions & Exercises

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is Redis primarily used for?

Redis is a popular database technology. What is its main use?

A A tool for managing large files and documents

B A traditional disk-based relational database for complex joins

C A fast in-memory data store used for caching and real-time data processing

D A programming language for building web applications

💡 Hint

Think about speed and memory when you hear Redis.

Redis stores data in memory, making it very fast for caching and real-time tasks.

🧠 Conceptual

intermediate

Which data structures does Redis support?

Redis supports several data structures. Which of these is NOT supported by Redis?

A Graphs and Geospatial indexes

B Sorted Sets, Bitmaps, HyperLogLogs

C Strings, Lists, Sets, Hashes

D Relational tables with foreign keys

💡 Hint

Redis is not a relational database.

Redis supports many data structures but does not support relational tables or foreign keys.

❓ query_result

advanced

What is the output of this Redis command?

Given the following Redis commands, what will be the output of the last command? SET user:1 "Alice" GET user:1

Redis

SET user:1 "Alice"
GET user:1

A Alice

B user:1

C nil

D Error: wrong number of arguments

💡 Hint

GET returns the value stored at the key.

The SET command stores the string "Alice" at key user:1. GET returns that value.

📝 Syntax

advanced

Which Redis command syntax is correct to add a member to a set?

You want to add the member "blue" to the set "colors". Which command is correct?

A SADD colors blue

B ADD colors blue

C SET colors blue

D PUSH colors blue

💡 Hint

Sets use SADD to add members.

SADD is the Redis command to add members to a set. Other commands are invalid or for different data types.

❓ optimization

expert

How to optimize Redis memory usage for large string values?

You store many large strings in Redis but want to reduce memory usage. Which approach is best?

A Use Redis lists instead of strings for large text

B Use Redis compression modules or compress strings before storing

C Increase Redis maxmemory setting without changing data

D Store strings as separate keys for each character

💡 Hint

Think about reducing size before storing.

Compressing strings before storing or using Redis modules that support compression reduces memory usage effectively.