REDIS Remote dictionary server KALI ROHAN KOKA AZEEM

REDIS (Remote dictionary server) KALI ROHAN KOKA AZEEM HIRANI

WHAT ISREDIS A Simple database Implementing a Dictionary where keys are associated with values. For e. g. : It can set the key “surname_1987” to the string “Rohan”. It is open sourced. First released in March 2009. Redis takes entire dataset in memory. Dump of dataset is created and loaded whenever server is restarted. Speed is the key feature. Estimated 80000+ operations per second at least

Redis data types Values can be associated with: Strings – Binary safe so they can hold text, images, compressed data, etc. Lists – Lists of Strings for operations like append, list length, range of elements, sorting of lists Sets – Addition and deletion of elements from a set, Intersection, union, subtraction, etc. Zsets – Zadd, Zrange, Zscore, Zcard

Similarities with memcached Some features like those of Memcached: All data lives in the memory. Faster, Light weight Data exists in the memory Support Multiple databases Support for Integer counters Atomic operations

Differences with memcached Memcached is not persistent. Memcached does not save as the purpose is to be used only as a cache. Redis has capability of being used as main DB for the application. Memcached uses key value model like Redis but keys can be just string. In Redis, values can be Lists, Sets, Zsets.

Overview of Commands Strings- get, set, increment, decrement Lists- push, pop, length, range, trim Sets- add, remove, length, intersect Some more commands useful – save, lastsave (can be used to force and verify disk persistance)

Database Commands These type of commands operate on database. They do not operate on individual keys. SELECT MOVE FLUSHALL SHUTDOWN SLAVEOF DBSIZE INFO MONITOR

Advantages of using REDIS Pick your own Level. Redis supports Persistence Replication – Works as a master slave Publish/Subscribe

Disadvantages Unreliable Indexes take a lot of RAM.