ElasticSearch is a distributed, RESTful, free/open source search server based on Apache Lucene. It is developed by Shay Banon and is released under the terms of the Apache License. ElasticSearch is developed in Java.
HistoryShay Banon created Compass in 2004. While thinking about the third version of Compass he realized that it would be necessary to rewrite big parts of Compass to "create a scalable search solution". So he created "a solution built from the ground up to be distributed" and used a common interface, JSON over HTTP, suitable for programming languages other than Java as well. Shay Banon released the first version of ElasticSearch in February 2010.
In a French interview some more ideas are explained.
FeaturesElasticSearch can be used to search all kinds of documents. It provides a scalable search solution, has near real-time search and support for multitenancy. "ElasticSearch is distributed, which means that indices can be divided into shards and each shard can have zero or more replicas. Each node hosts one or more shards, and acts as a coordinator to delegate operations to the correct shard(s). Rebalancing and routing are done automatically [...]".
It uses Apache Lucene and tries to make all features of it available through the JSON and Java API. It supports facetting and percolating, which can be useful for notifying if new documents match for registered queries.
Another feature is called 'Gateway' and handles the long term persistence of the index- i.e. an index can be recovered from the Gateway in a case of a server crash. ElasticSearch supports real-time GET requests, which makes it suitable as a NoSQL solution, but it lacks distributed transactions.
Comparison to other softwareApache Solr is another open source search server built on top of Apache Lucene. There are some documents comparing features or performance of Apache Solr and ElasticSearch. Sematext published a series of posts starting with Solr vs. ElasticSearch Overview comparing ElasticSearch vs. Solr (Solr 4.0, aka SolrCloud, more specifically) in the most comprehensive and neutral comparison to date. In an article from Ryan Sonnek it will be pointed out how Apache Solr and ElasticSearch compare regarding near real-time indexing and searching.
An article in the German iX magazine from Peter Karich lists advantages and disadvantages of ElasticSearch  - an English slide is also available, which can be summarized as follows:
- ElasticSearch is distributed. No separate project required. Replicas are near real-time too, which is called "Push replication".
- ElasticSearch fully supports the near real-time search of Apache Lucene.
- Handling multitenancy is not a special configuration, whereas a more advanced setup is necessary with Solr.
- ElasticSearch introduces the concept of the Gateway, which makes full backups easier.
- Only one main developer. This can be mitigated since there is now the company ElasticSearch where not only one man is involved.
- Use parent/child feature instead of Solr's results grouping or have a look into this issue .
- No XML support, only JSON
- Common container deployment (as a WAR file) is in development plugin
- No convenient wrapper for Java beans as the @Field annotation in SolrJ
UsersThere are already smaller and some bigger companies using ElasticSearch, including StumbleUpon, Mozilla  and Github.
- What's Next 2011 
- Berlin Buzzwords 2010-2012 
- PHP UK 2011 
- YAPC::EU 2010 
With Proquest Udini, we have created the worlds largest online article store, and aim to be the center for researchers all over the world. We connect to a 700M solr cluster for search, but have recently also implemented a search component with ElasticSearch. We will discuss how we did this, and how we want to use the 30M index for scientific citation recognition. We will highlight lessons learned in integrating ElasticSearch in our virtualized EC2 environments, and challenges aligning with our continuous deployment processes.
- ElasticSearch Commiters
- The Future of Compass
- Initial version of ElasticSearch
- French interview
- Official Website
- "elasticsearch Guide: Gateway". elasticsearch. Retrieved October 6, 2012.
- ElasticSearch as database
- No transaction support
- Solr vs. ElasticSearch Overview
- Comparison of Apache Solr and ElasticSearch regarding near real-time indexing
- iX Magazine Article "Immer Flexibel"
- Feature comparison of Apache Solr and ElasticSearch
- Video, Berlin Buzz 2011
- Berlin Buzz 2011
- ElasticSearch users
- StumbleUpon uses ElasticSearch
- Why Mozilla uses ElasticSearch
- ElasticSearch helps Mozilla Metrics team
- A Whole New Code Search
- Video, InfoQ presentation
- Berlin Buzzwords 2010
- Mozilla Metrics at Berlin Buzzwords 2010
- Berlin Buzzwords 2012
- Zmievski, Andrei (25 Feb, 2011). "99 Problems, But The Search Ain't One (PHP UK 2011)". elasticsearch. Retrieved October 6, 2012.
- YAPC::EU 2010
In this session we will explore elasticsearch, specifically, how to handle huge amount of data with it, how to effectively search it, and last, use facets to derive complex, (near) real time analytics from it.
Amsterdam-based Elasticsearch, which has now raised a total of $34 million, generates revenue by teaching people how to use the tool at training courses and help them solve problems by way of support
subscriptions. Introduced in 2010 after founder Shay Banon developed it in his free time, the open-source Elasticsearch program today gets downloaded 200,000 times a month. Banon launched the company itself six months ago, when CEO Steven Schuurman got involved, in time to take on a Series A round.
Elasticsearch can make quick work of searching billions of documents and petabytes of data, structured and unstructured alike, said Banon, now the company’s chief technology officer. A single developer can use it to find needles amid haystacks of tweets and other kinds of data, eliminating the need for a team of data scientists, Banon said.
Like LucidWorks, Elasticsearch was developed on top of open-source Apache Lucene. But LucidWorks (which until August 2012 was named Lucid Imagination and has raised at least $16 million) focuses more on the enterprise, as my colleague Barb Darrow has reported, while Elasticsearch has caught on with startups and enterprises alike in several industries, according to Schuurman.
This is a list of articles about search engines, including web search engines, selection-based search engines, metasearch engines, desktop search tools, and web portals and vertical market websites that have a search facility for online databases.
Alternatives to Google. Various search engines that you can use instead of Google, with some interesting sites like Google that are useful to know about.
For a text version of this video, as well as links to the various search engines, visit:
- Baidu (Chinese, Japanese)
- Sogou (Chinese)
- Soso.com (Chinese)
- Yodao (Chinese)
P2P search engines
- Yippy (formerly Clusty)
- PCH Search and Win
Geographically limited scope
- Accoona, China/United States
- Alleba, Philippines
- Ansearch, Australia/United States/United Kingdom/New Zealand
- Biglobe, Japan
- Daum, Korea
- Goo, Japan
- Guruji.com, India
- Leit.is, Iceland
- Maktoob, Arab World
- Miner.hu, Hungary
- Najdi.si, Slovenia
- Naver, Korea
- Onkosh, Arab World
- Rambler, Russia
- Rediff, India
- SAPO, Portugal/Angola/Cabo Verde/Mozambique
- Search.ch, Switzerland
- Sesam, Norway, Sweden
- Seznam, Czech Republic
- Walla!, Israel
- Yandex.ru, Russia/Turkey
- Yehey!, Philippines
- ZipLocal, Canada/United States
- Getit Infoservices Private Limited
- GenieKnows (United States and Canada)
- Nexis (Lexis Nexis)
- Thomasnet (United States)
- Funnelback: Funnelback Search
- Jumper 2.0: Universal search powered by Enterprise bookmarking
- Oracle Corporation: Secure Enterprise Search 10g
- Q-Sensei: Q-Sensei Enterprise
- TeraText: TeraText Suite
- Bixee.com (India)
- CareerBuilder.com (USA)
- Craigslist (by city)
- Dice.com (USA)
- Eluta.ca (Canada)
- Hotjobs.com (USA)
- Incruit (Korea)
- Indeed.com (USA)
- LinkUp.com (USA)
- Monster.com (USA), (India)
- Naukri.com (India)
- Yahoo! HotJobs (Countrywise subdomains, International)
- Bing Health
- Bioinformatic Harvester
- EB-eye EMBL-EBI's Search engine
- Entrez (includes Pubmed)
- GoPubMed (knowledge-based: GO - GeneOntology and MeSH - Medical Subject Headings)
- Nextbio (Life Science Search Engine)
- Quertle (Semantic search of the biomedical literature)
Real estate / property
- Wazap (Japan)
By information typeSearch engines dedicated to a specific kind of information
- Bing Videos
- Google Video
- Munax's PlayAudioVideo
- TV Genius
- Yahoo! Video
BitTorrentThese search engines work across the BitTorrent protocol.
Search Here: http://www.cdnpal.com
CloudSearch engines listed below find various types of files that have been stored in the cloud and made publicly available.
- Bing Shopping
- Google Shopping (formerly Google Product Search and Froogle)
- Shopzilla (also operates Bizrate)
Question and answer
- Ask Me Help Desk
- Stack Overflow/Stack Exchange Network
- Yahoo! Answers
Privacy search engines
Open source search engines
- Lemur Toolkit & Indri Search Engine
- Sciencenet (for scientific knowledge, based on YaCy technology)
- Terrier Search Engine
- Wikia Search
Semantic browsing engines
Social search engines
- ChaCha Search
- Wink provides web search by analyzing user contributions such as bookmarks and feedback
Visual search engines
Desktop search engines
|Autonomy||Windows||IDOL Enterprise Desktop Search.||Proprietary, commercial|
|Beagle||Linux||Open source desktop search tool for Linux based on Lucene. Unmaintained since 2009.||A mix of the X11/MIT License and the Apache License|
|Copernic Desktop Search||Windows||Free for home use|
|Docfetcher||Cross-platform||Open source desktop search tool for Windows and Linux, based on Apache Lucene||Eclipse Public License|
|dtSearch Desktop||Windows||Proprietary (30 day trial)|
|Everything||Windows||Find files and folders by name instantly on NTFS volumes||Freeware|
|Google Desktop||Linux, Mac OS, Windows||Integrates with the main Google search engine page. 5.9 Release now supports x64 systems. As of September 14, 2011, Google has discontinued this product.||Freeware|
|GNOME Storage||Linux||Open Source desktop search tool for Unix/Linux||GPL|
|imgSeek||Linux, Mac OS, Windows||Desktop content-based image search||GPL v2 |
|InSight Desktop Search||Windows||Metadata-based search utility||Freeware|
|ISYS Search Software||Windows||ISYS:desktop search software.||Proprietary (14 day trial)|
|Locate32||Windows||Graphical port of Unix's locate & updatedb||BSD License|
|Lookeen||Windows||Outlook Search Tool, with integrated Desktop Search||Proprietary (14 day trial)|
|Meta Tracker||Linux, Unix||Open Source desktop search tool for Unix/Linux||GPL v2 |
|Recoll||Linux, Unix||Open Source desktop search tool for Unix/Linux||GPL |
|Spotlight||Mac OS||Found in Apple Mac OS X "Tiger" and later OS X releases.||Proprietary|
|Strigi||Linux, Unix, Solaris, Mac OS X and Windows||Cross-platform open source desktop search engine||LGPL v2 |
|Terrier Search Engine||Linux, Mac OS, Unix||Desktop search for Windows, Mac OS X (Tiger), Unix/Linux.||MPL|
|Tropes Zoom||Windows||Semantic Search Engine.||Freeware and commercial|
|Windows Search||Windows||Part of Windows Vista and later OSs. Available as Windows Desktop Search for Windows XP and Server 2003. Does not support indexing UNC paths on x64 systems.||Proprietary, freeware|
- Everyclick (formerly based on Ask.com)
- Forestle (an ecologically motivated site supporting sustainable rain forests - formerly based on Google)
Defunct or acquired search engines
- Brainboost (Public engine no longer exists, acquired by Answers, Inc.)
- BRS/Search (now OpenText Livelink ECM Discovery Server)
- ChunkIt! (now "yolink!") (Public engine no longer exists)
- Direct Hit Technologies (acquired by Ask Jeeves in January, 2000)
- Google Answers
- IBM STAIRS
- LeapFish (Public engine no longer exists)
- Lotus Magellan
- MetaLib (Public engine no longer exists)
- mozDex (No longer exists)
- Myriad Search (No longer exists)
- Overture.com (formerly GoTo.com, now Yahoo! Search Marketing)
- RetrievalWare (acquired by Fast Search & Transfer and now owned by Microsoft)
- Scroogle (Google Scraper)
- Wikia Search
- World Wide Web Worm
- List of academic databases and search engines
- List of semantic search engines
- List of web directories
- Search aggregator
- Search engine optimization
- Category:Search engine software
- According to COPYING in SVN trunk on SourceForge.
- According to http://www.softpedia.com/get/Internet/Servers/Database-Utils/Locate32.shtml
- According to COPYING in SVN trunk.
- According to .
- According to COPYING in version 0.5.10 tar.bz2 package.
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