Redis Interview Questions and Answers

Redis Interview Questions and Answers

Redis is an open-source (BSD licensed), in-memory database project implementing a distributed, and in-memory key-value store with optional durability. Redis supports different kinds of abstract data structures, such as strings, lists, maps, sets, sorted sets, hyperloglogs, bitmaps and spatial indexes. The project is mainly developed by Salvatore Sanfilippo and is currently sponsored by Redis Labs. Redis Labs creates and maintains the official Redis Enterprise Pack. Redis has built-in replication, Lua scripting, LRU eviction, transactions and different levels of on-disk persistence, and provides high availability via Redis Sentinel and automatic partitioning with Redis Cluster.

Redis is an in-memory key value data store written in ANSI C programming language by Salvatore Sanfilippo.  Redis not only supports string datatype but it also supports list, set, sorted sets, hashes datatypes, and provides a rich set of operations to work with these types. If you have worked with Memcached (an in-memory object caching system) you will find that it is very similar, but Redis is Memcached++.  Redis not only supports rich datatypes, it also supports data replication and can save data on disk.

The name Redis means REmote Dictionary Server. Salvatore Sanfilippo, the original developer of Redis, was hired by VMware in March, 2010. In May, 2013, Redis was sponsored by Pivotal Software (a VMware spin-off). In June 2015, development became sponsored by Redis Labs. (Wikipedia says)

What is Redis?

Why Redis?

What are the key features of Redis?

What are Redis Supported Languages?

In which language Redis is written?

Which are the most popular companies using redis?

Can you explain Redis Data Structure?

Can you explain Persistence?

Can you explain Redis Replication?

What happens if Redis runs out of memory?

What is AOF?

What is the difference between overriding a value by using set vs append?

What is difference between MemcacheD and Redis?

What are the Similarities between Memcached and Redis?

What is the difference between Redis and RDBMS?

How can you improve the durability in redis?

How do i move a redis database from one server to another?

Can you list the operation keys?

How can you use redis with .net application?

How does redis differ from mongodb? Is there a use case when for redis if using mongodb?

How to check redis is running?

How to set multiple values (array) in redis?

How can use SAVE command in Redis Backup & Restore?

How do I move a redis database from one server to another?

What do you mean by redis is binary safe?

How to stop Redis?

What are the pros and cons of Redis?