Redis interview questions

Top Redis Interview Questions and answers

#1 Question

What is Redis?

Redis is an open source released under BSD licensed, in-memory data structure store, it can be used as a database, cache and message broker.

#2 Question

List the data structures supported by Redis.

Redis supports following Data Structures
  • Strings
  • Hashes
  • Lists
  • Sets
  • Sorted sets with range queries
  • bitmaps
  • Hyperloglogs
  • Geospatial indexes with radius queries

#3 Question

List some advantages of Redis?

Following are some advantages of Redis
  • Exceptionally Faster than others
  • Supports for rich data types like Hashes, Sets, bitmaps
  • Rich client-side library.
  • Support for server-side locking.
  • Operations are atomic.

#4 Question

List some commonly used Redis commands?

Some commonly used Redis commands list
Command NameDescription
APPENDAppend a value to a key
AUTHAuthenticate to the server
BGREWRITEAOFAsynchronously rewrite the append-only file
BGSAVEAsynchronously save the dataset to disk
BITCOUNTCount set bits in a string
CLIENT LISTGet the list of client connections
CLUSTER INFOProvides info about Redis Cluster node state

Read more from Redis Commands List

#5 Question

In which language Redis is written?

Redis is NoSql  based Key-value Database, which is written in ANSI C

#6 Question

List some Redis Clients supported by PHP?

Below are some Redis Clients supported by PHP Programming Language
  • amphp/redis
  • cheprasov/php-redis-client
  • Credis
  • PHP Redis implementation / wrapper
  • PHP Sentinel Client
  • phpredis

#7 Question

What is redis-cli.

redis-cli is the Redis command line interface, a simple program that allows to send commands to Redis, and read the replies sent by the server, directly from the terminal.

#8 Question

Explain REPL

REPL stands for Read Eval Print Loop. It an interactive mode where the user types commands and get replies.

#9 Question

List the programming languages supported by Redis?

Redis supports a wide range of programming language. Some major programming languages supported by Redis are PHP, Java, Python, Scala, Perl, Ruby, C#, and C++.
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