Question 1

What is Redis and what are its primary use cases?

Accepted Answer

Redis is an in-memory, open-source data structure store that can be used as a database, cache, or message broker. Its primary use cases include caching data for faster retrieval, session management, rate-limiting, queuing tasks for background processing, and real-time analytics.

Question 2

What data structures does Redis support?

Accepted Answer

Redis supports multiple data structures, including strings, lists, sets, hash maps, and sorted sets. It also has support for geospatial index and queries, bitmaps, and hyperloglogs for different types of data manipulation and access patterns.

Question 3

Can Redis persist data on disk?

Accepted Answer

Yes, Redis can persist data on disk using two methods: snapshots (RDB) and append-only file (AOF). Snapshots create a point-in-time copy of the dataset, while AOF logs every write operation. You can configure Redis to use either of these methods or a combination of both.

Question 4

How does Redis handle concurrency and data consistency?

Accepted Answer

Redis uses a single-threaded event-driven architecture. This means that it serves one request at a time, avoiding concurrency and consistency issues. It also supports optimistic locking using the WATCH command, enabling transactional functionality to ensure data consistency in concurrent scenarios.

Question 5

What is clustering in Redis, and why is it useful?

Accepted Answer

Clustering in Redis is a distributed setup that allows multiple Redis instances to work together to store and serve data. It helps in horizontal scaling by partitioning the dataset among multiple nodes and expands the total available memory and processing power. Clustering also improves fault tolerance and high availability by replicating data across multiple nodes.

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