Job Interview Questions and Answers Directory

Redis Easy technical

Q1. What are the Redis data structures and what is each used for?

Redis exposes several core data types, each with tailored commands. - Strings: counters, cached serialized objects and rate limiters using INCR and SETEX. - Hashes: objec...

#redis #data-structures #caching

2 Answer

Redis Medium technical

Q2. How does Redis persistence work with RDB and AOF?

Redis offers two persistence mechanisms. RDB takes point-in-time snapshots at configured intervals, for example save 900 1 snapshots after 900 seconds if at least one key...

#redis #persistence #durability

3 Answer

Redis Medium technical

Q3. Explain key expiry and eviction policies in Redis.

You set a time to live with EXPIRE, SETEX or PEXPIRE. Redis removes expired keys lazily on access and also runs a background sampling cycle that actively deletes expired ...

#redis #expiry #eviction

1 Answer

System Design Hard system-design

Q4. Explain caching strategies and common failure modes.

Strategies: - Cache-aside (lazy loading): app checks cache, on miss reads DB and populates. Most common. - Read-through: cache library fetches on miss. - Write-through: w...

#caching #redis #invalidation #performance

3 Answer

Redis Medium technical

Q5. What is the cache-aside pattern and how do you keep the cache consistent?

In cache-aside the application checks the cache first. On a miss it reads from the database, writes the value into the cache with a TTL, and returns it. On writes, the co...

#redis #cache-aside #consistency

1 Answer

Redis Hard coding

Q6. How do you implement a distributed lock with Redis?

A common implementation is SET key value NX PX ttl. NX sets the key only if it does not exist, and PX gives the lock an expiry so a crashed holder cannot deadlock the sys...

#redis #locking #concurrency

2 Answer

Redis Medium technical

Q7. What is the difference between Redis Pub/Sub and Streams?

Pub/Sub is fire-and-forget messaging. Publishers send to a channel and subscribers receive in real time, but messages are not stored. An offline subscriber misses them, a...

#redis #pubsub #streams

2 Answer

Redis Hard system-design

Q8. How does Redis Cluster provide horizontal scaling?

Redis Cluster shards data across nodes using 16384 hash slots. Each key maps to a slot via CRC16(key) mod 16384, and slots are assigned to masters. Clients may query any ...

#redis #cluster #scaling

1 Answer

Redis Easy technical

Q9. What is a Redis sorted set and what are common use cases?

A sorted set stores unique members, each with a floating-point score, kept ordered by score. Operations are O(log N), and you can query by rank or by score range. ```sh Z...

#redis #sorted-set #leaderboard

2 Answer

Caching Strategies Medium technical

Q10. How do cache eviction policies differ?

Eviction decides what to remove when the cache is full or memory is constrained: - LRU (least recently used): evicts the item not accessed for the longest time. A solid d...

#eviction #lru #redis

1 Answer