30+ Redis Interview Questions

30+ Redis Interview Questions

Redis Interview Questions

1) What is Redis? 

Redis is an open-source, advance key esteem information store and reserve. It is additionally alluded as an information structure server which keys contains strings, yet in addition hashes, sets, records, and arranged sets.

2) What is the importance of Redis? 

Redis represents REmote DIctionary Server.

3) How is Redis unique in relation to different databases? 

Redis is a NoSQL, Opensource, in-memory information structure store. It pursues the guideline of key-esteem store.

It is very quick, determined, versatile and underpins numerous dialects, for example, C, C++, C#, Clojure, Common Lisp, D, Dart, Erlang, Go, Haskell, Haxe, Io, Java, JavaScript (Node.js), Julia, Lua, Objective-C, Perl, PHP, Pure Data, Python, R, Racket, Ruby, Rust, Scala, Smalltalk and Tcl.

4) In which language Redis is composed? 

Redis is written in ANSI C and generally utilized for store arrangement and session the board. It makes interesting keys for store esteems.

5) What is the use of Redis? 

Redis is a unique key-esteem store database that can work as a NoSQL database or as a memory-reserve store to improve execution when serving information that is put away in framework memory.

6) How to interect with Redis? 

After the establishment of the server you can run the Redis Client given by redis establishment or you can open the direction brief and utilize the accompanying order:


By utilizing any of them, you can interect with Redis.

7) Which are the most famous organizations utilizing Redis? 

Twitter, Github, Stackoverflow and so on are the most mainstream organizations utilizing Redis.

8) What are the principle highlights of Redis? 

Following are the fundamental highlights of Redis:

Redis is extremely easy to introduce setup and oversee.

Redis is quick. It can execute 100000 inquiries for each second.

Redis is quick since information is being determined in memory just as put away on the circle.

Redis is quick since it stacks the entire dataset in essential memory.

Redis activities chipping away at various information types are nuclear so these tasks can be practiced securely for example to set or expand a key, include or expel components from a set or increment a counter.

It underpins different kinds of information structure, for example, strings, hashes, sets, records, arranged sets and so on.

Redis underpins an assortment of dialects for example C, C++, C#, Ruby, Python, Twisted Python, PHP, Erlang, Tcl, Perl, Lua, Java, Scala and so on.

On the off chance that your most loved language isn't upheld yet, you can compose your very own customer library, as the Protocol is quite straightforward.

Redis underpins straightforward ace to slave replication.

Redis is versatile.

9) Explain the Replication Features of Redis? 

Replication is essential so as to document abnormal state of accessibility in huge information frameworks. The information should be duplicated at n number of spots. This pursues the ace slave approach where the ace duplicate is kept up by ace slave and imitated to n different hubs.

10) What are the upsides of utilizing Redis? 

Following is a rundown of some critical preferences of Redis:

Redis is extremely quick.

It underpins a server-side locking.

It has a rich customer side library.

It is a decent counter.

It bolsters Atomic Operation.

11) What are the impediments/restrictions of utilizing Redis? 

Following are the impediments/restrictions of Redis:

It is single strung.

It has got constrained customer support for steady hashing.

It has critical overhead for steadiness.

It isn't conveyed generally.

12) What is the distinction among Redis and RDBMS? 

There are a great deal of contrasts among Redis and RDBMS:

Redis is a NoSQL database while RDBMS is a SQL database.

Redis pursues the key-esteem structure while RDBMS pursues the table structure.

Redis incredibly quick while RDBMS is nearly moderate.

Redis stores all the dataset in essential memory while RDBMS stores its dataset in auxiliary memory.

Redis is commonly used to store little and every now and again utilized documents while RDBMS is utilized to store enormous records.

Redis gives just authority backing to Linux, BSD, Mac OS X, Solaris. It doesn?t give official help to Windows as of now while RDBMS offers help for both.

13) Differentiate Memcached and Redis?
Memcached Redis
Memcached only does caching information. It provides some more functionalities like replication and persistence along with caching information.
Memcached supports the functionality of LRU (Least Recently Used) eviction of values. LRU is not supported by Redis.
In Memcached, when they overflow memory, the one you have not used recently (LRU- Least Recently Used) will get deleted. In Redis, there is a time set for each function, Three keys are maintained, the one, which is closest to expiry, will get deleted.
CAS (Check and Set) is supported by Memcached. CAS is not supported by Redis.
Array objects are needed to be serialized in order to get saved. We need to unserialize them for their retrieval. Redis has got stronger data structures; it can handle strings, binary safe strings, list of binary safe strings, sorted lists, etc.
Memcached has at most 250 bytes length. Redis has at most 2 GB key length.
It is Multi-threaded It is single threaded.

14) Mention Operation Keys of Redis. 

TYPE key

TTL key

Lapse key seconds

EXPIREAT key timestamp


DEL key

15) Which are the distinctive information types utilized in Redis? 

There are for the most part 5 kinds of information types bolstered by Redis:





Arranged Sets

16) We all realize that Reds is quick, yet is it likewise sturdy? 

In Redis, there is dependably an exchange of among toughness and speed. On account of framework disappointment, it might lose information which isn't put away.

17) How would you be able to improve the strength of Redis? 

At whatever point another order is added to the add log record, call Fsysnc() each time.

Continue calling Fsysnc() in consistently. Regardless of the 1 second information lose on account of framework falls flat.

18) What are the concerned things while utilizing Redis? 

Reliable strategy choice so as to name and prefix the keys. Namespace the executives.

Make key prefixes vault which can outline reports to their proprietor applications.

Planning, executing and testing the Garbage accumulation system for each class we keep into the redis design.

Keep up a sharding library before putting such a great amount into the application.

19) How would you be able to utilize Redis with .Net application? 

To utilize Redis in .Net applications, pursue these means:

To start with, Download Redis Server.

Introduce Redis Server.

Download Redis Client.

Set Configuration into Web.config File.

Use Redis Client Class.