Presenter: Mubashar IqbalSoftware Engineer

Classical variant - store data in a relational database:

• MySQL

• PostgreSQL

• H2

• SQLite and many more...

Modern trend in a Web programming: • Store data in NoSQL databases

Databases

• Non-relational database management system

• Did not expose the standard SQL interface

• Does not conform to ACID

• Working with a huge quantity of data

• Does not require a relational model

• Distributed, fault-tolerant architecture

NoSQL Introduction

Categories of NoSQL Databases

Key-ValueMemcached, Redis, Riak

Column FamilyCassandra, HBase

DocumentMongoDB, CouchDB

Graph

Neo4j, InfoGrid

Redis

Redis means Remote Dictionary Server

Open Source

Key-Value Data store

Data structure server

In-Memory Dataset

Written in ANSI C and Sponsored by Pivotal.

http://redis.io/topics/introduction

Why and when you should use Redis? Caching Master-slave replication, automatic failover High-IO workloads Distributed Locks Data that expires Cookie storage Analytics Ad Targeting Search engines Small Data Bigger Data Forums

Who is using Redis?

http://redis.io/topics/whos-using-redis

Storing lots of Pinterest lists in Redis

Next time you log in to Pinterest, remember that Redis is running in the background and storing several types of lists for you as a user:

A list of users who you follow A list of boards (and their related users) who you follow A list of your followers A list of people who follow your boards A list of boards you follow A list of boards you unfollowed after following a user The followers and unfollowers of each board

InstallationLinux: 1. $ wget http://download.redis.io/releases/redis-2.8.9.tar.gz 2. $ tar xzf redis-2.8.9.tar.gz 3. $ cd redis-2.8.9 4. $ make 5. $ sudo make install 6. $ cd utils 7. $ sudo ./install_server.sh

Windows:1. Download the latest .exe package from

http://github.com/MSOpenTech/redis2. Running the exe will install Redis as a service and install the Redis client.

Configuration

Redis is able to start without a configuration file using a built-in default configuration.

The proper way to configure Redis is by providing a Redis configuration file, usually called redis.conf.

Port: 6379 Timeout: 300 Maxclients 10000 Maxmemory <bytes> Save 900 1

Running Redis Server and Client

Once the script completes, the redis-server will be running in the background. You can start and stop redis with these commands.

sudo service redis_6379 startsudo service redis_6379 stop

Access the redis database by typing the following command.

redis-cli

Redis Clients

Phpredis – Redis client written in C for PHP.

Redis-py – Mature Redis client for Python.

Redis-rb – Very stable & Muture Client for Rubys

Scala-redis – Mature Redis client for Scala

Node_redis – Recommended client for node.

Jedis – Java client library for Redis.

Eredis – A Redis erlang client library.

Example Code

Write a simple php script to test redis php client:

<?php $redis=new Redis() or die("Can't load redis client."); $redis->connect('127.0.0.1', 6379); $redis->set('set_testkey', 1); ?>

Parameters:Host: string. can be a host, or the path to a unix domain socketPort: int, optional

Return value:BOOL: TRUE on success, FALSE on error.

Redis Data Types

Redis is often referred to as a data structure server since keys can contain:

Strings

Lists

Sets

Hashes

Sorted Sets

http://redis.io/topics/data-types

Strings

Most basic kind of Redis value Binary safe - can contain any kind of data Max 512 Megabytes in length Can be used as atomic counters using commands in the

INCR family

APPEND – Append a value to a key

GET – Get the value of a key

SET – Set the string value of a key

MGET – Get the values of all the given keys

MSET – Set multiple keys to multiple values

Lists Lists of strings, sorted by insertion order Add elements to a Redis List pushing new elements on the

head (on the left) or on the tail (on the right) of the list

LSET – Set the value of an element in a list by its index

LLEN – Get the length of a list

LREM – Remove elements from a list

LINSERT – Insert an element before or after another

element in a list

LRANGE – Get a range of elements from a list

LPOP – Remove and get the first element in a list

RPOP – Remove and get the last element in a list

Sets

Redis Sets are an unordered collection of Strings. You can track unique things using Redis Sets.

SADD – Add one or more members to a set

SISMEMBER – Determine if a given value is a member of a set

SMEMBERS – Get all the members in a set

SPOP – Remove and return a random member from a set

SRANDMEMBER – Get one or multiple random members from a

set

SREM – Remove one or more members from a set

Hashes Map between string fields and string values Every hash can store more than 4 billion field-value pairs.

HSET – Set the string value of a hash field

HGET – Get the value of a hash field

HMGET – Get the values of all the given hash fields

HMSET – Set multiple hash fields to multiple values

HLEN – Get the number of fields in a hash

HKEYS – Get all the fields in a hash

HGETALL – Get all the fields and values in a hash

Sorted Sets Every member of a Sorted Set is associated with score, that is used in order to take the sorted set ordered, from the smallest to the greatest score You can do a lot of tasks with great performance that are

really hard to model in other kind of databases Probably the most advanced Redis data type

ZADD – Add one or more members to a sorted set, or update its

score if it already exists

ZREM – Remove one or more members from a sorted set

ZRANGE – Return a range of members in a sorted set, by index

ZINCRBY – Increment the score of a member in a sorted set

ReplicationMaster-slave replication that allows slave Redis servers to be exact copies of master servers. A master can have multiple slaves. Slaves are able to accept connections from other slaves.

Replication can be used both for scalability and for data redundancy.

Slave instance facility for scaling out read requests or mitigate a disaster recovery scenario.

Setup the Master Server

To configure replication is very simple just add the following line to the slave configuration file:

slaveof 192.168.1.1 6379

Replace 192.168.1.1 6379 with your master IP address and port.

Replication only needs to be defined on Slave systems, the Master server does not require any special configuration.

Performance

Popularity of Redis:

Speed

Rich semantics

Stability

Durability / Persistence

- Redis snapshots - Append-only file (AOF)

Comparison

Resources

1. http://www.redis.io

2. http://bencane.com/2013/11/12/installing-redis-and-setting-up-master-slave-replication/

3. http://oldblog.antirez.com/post/redis-memcached-benchmark.html

4. http://oldblog.antirez.com/post/update-on-memcached-redis-benchmark.html

5. http://blog.gopivotal.com/pivotal/case-studies-2/using-redis-at-pinterest-for-billions-of-relationships