Why We Need

Performance
No Locking
Auto Scale up / down
Full Text Search
Easy To Use

Case Studies

Usage Statistics

source: http://www.elastichq.org/elasticsearchstats.php

what is elastic search?

Elasticsearch is a highly available, highly customizable and distributed search engine.

Document

Json Object
Core filed types (String, Numbers, Booleans)
Complex field types (Arrays, Objects)
Additional filed types (GeoPoints, Biniaries,)

Node

a running ElasticSearch instance (JVM)

Cluster

a group of nodes

Shard

a part of an index
a Luvene index under the hood
primary: unique in the cluster
replica: one or more copy of the primary

Key Features

distributed
high availability
multi tenancy
full text search
document oriented
schema free
restful

build on top of apache lucene

Apache Lucene is a high performance, full-featured Information Retrieval library, written in Java. Elasticsearch uses Lucene internally to build its state of the art distributed search and analytics capabilities.

Distributed

Start small, but will grow with your business. It is built to scale horizontally out of the box. As you need more capacity, just add more nodes, and let the cluster reorganize itself.

Auto Scale Up / Down

high availability

They will detect and remove failed nodes, and reorganize themselves.

Multi Tenancy

A cluster can host multiple indices which can be queried independently or as a group

Full Text Search

Search comes with multi-language support, a powerful query language, support for geolocation, context aware did-you-mean suggestions, autocomplete and search snippets.

How It works

Document Oriented

Store complex real world entities in Elasticsearch as structured JSON documents. All fields are indexed by default, and all the indices can be used in a single query, to return results at breath taking speed.