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1. MongoDB
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MongoDB
MongoDB Logo.png
Developer(s)
MongoDB Inc.
Initial release
2009
Stable release
2.4.8 / 1 November 2013
Preview release
2.5.2 / 26 August 2013
Development status
Active
Written in C++
Operating system Cross-platform
Available in
English
Type Document-oriented database
License
GNU AGPL v3.0 (drivers: Apache license)
Website
www.mongodb.org
MongoDB (from "humongous") is a cross-platform document-oriented database
system. Classified as a NoSQL database, MongoDB eschews the traditional tablebased relational database structure in favor of JSON-like documents with dynamic
schemas (MongoDB calls the format BSON), making the integration of data in
certain types of applications easier and faster. Released under a combination of
the GNU Affero General Public License and the Apache License, MongoDB is free
and open source software.
First developed by 10gen (now MongoDB Inc.) in October 2007 as a component of a
planned platform as a service product, the company shifted to an open source
development model in 2009, with 10gen offering commercial support and other
services.[1] Since then, MongoDB has been adopted as backend software by a
number of major websites and services, including Craigslist, eBay, Foursquare,
SourceForge, and The New York Times, among others. MongoDB is the most popular
NoSQL database system.[2]
Contents [hide]
1 History
2 Licensing and support
3 Main features
4 Criticisms
5 Language support
6 Management and graphical front-ends
6.1 MongoDB tools
7 Production Deployments
8 See also
9 References
10 Bibliography
11 External links
History[edit]
Development of MongoDB began in 2007, when the company (then named 10gen) was
building a platform as a service similar to Windows Azure or Google App Engine.
[3] In 2009, MongoDB was open sourced as a stand-alone product[4] with an AGPL
license.
From version 1.4 (March 2010), MongoDB has been considered production ready.[5]
The latest stable version, 2.4.8, was released on November 1, 2013.
Licensing and support[edit]
MongoDB is available for free under the GNU Affero General Public License.[4]
The language drivers are available under an Apache License. In addition, MongoDB
Inc. offers commercial licenses for MongoDB.gh[6]
Main features[edit]
The following is a brief summary of some of the main features:[7]
Ad hoc queries
MongoDB supports search by field, range queries, regular expression searches.
Queries can return specific fields of documents and also include user-defined
JavaScript functions.
Indexing

2. Any field in a MongoDB document can be indexed (indices in MongoDB are
conceptually similar to those in RDBMSes). Secondary indices are also available.
Replication
MongoDB provides high availability and increased throughput with replica sets.
[8] A replica set consists of two or more copies of the data. Each replica may
act in the role of primary or secondary replica at any time. The primary replica
performs all writes and reads by default. Secondary replicas maintain a copy of
the data on the primary using built-in replication. When a primary replica
fails, the replica set automatically conducts an election process to determine
which secondary should become the primary. Secondaries can also perform read
operations, but the data is eventually consistent by default.
Load balancing
MongoDB scales horizontally using sharding.[9] The user chooses a shard key,
which determines how the data in a collection will be distributed. The data is
split into ranges (based on the shard key) and distributed across multiple
shards. (A shard is a master with one or more slaves.)
MongoDB can run over multiple servers, balancing the load and/or duplicating
data to keep the system up and running in case of hardware failure. Automatic
configuration is easy to deploy, and new machines can be added to a running
database.
File storage
MongoDB can be used as a file system, taking advantage of load balancing and
data replication features over multiple machines for storing files.
This function, called GridFS,[10] is included with MongoDB drivers and available
with no difficulty for development languages (see "Language Support" for a list
of supported languages). MongoDB exposes functions for file manipulation and
content to developers. GridFS is used, for example, in plugins for NGINX[11] and
lighttpd.[12]
In a multi-machine MongoDB system, files can be distributed and copied multiple
times between machines transparently, thus effectively creating a load balanced
and fault tolerant system.
Aggregation
MapReduce can be used for batch processing of data and aggregation operations.
The aggregation framework enables users to obtain the kind of results for which
the SQL GROUP BY clause is used.
Server-side JavaScript execution
JavaScript can be used in queries, aggregation functions (such as MapReduce),
and sent directly to the database to be executed.
Capped collections
MongoDB supports fixed-size collections called capped collections. This type of
collection maintains insertion order and, once the specified size has been
reached, behaves like a circular queue.
Criticisms[edit]
MongoDB uses a readers-writer lock that allows concurrent read access to a
database but exclusive write access to a single write operation.[13] Before
version 2.2, this lock was implemented on a per-mongod basis. Since version 2.2,
the lock is implemented at the database level.[14] One approach to increase
concurrency is to use sharding.[15] In some situations, reads and writes will
yield their locks. If MongoDB predicts a page is unlikely to be in memory,
operations will yield their lock while the pages load. The use of lock yielding
expanded greatly in 2.2.[16]
Another criticism related to scalability is that only 2GB of memory may be used
on 32-bit systems, rather than the 4GB theoretically available; more memory is
available on 64-bit systems.[17] In some cases, this was due to the use of
MongoDB on 32-bit systems and their inherent memory limitations.[18] MongoDB
recommends users provide sufficient RAM for their working set.[19] Some users
encounter issues when their working set exceeds available RAM and the system
encounters page faults. MongoHQ, a provider of managed MongoDB infrastructure,
recommends a scaling checklist for large systems.[20]
Language support[edit]
MongoDB has official drivers for a variety of popular programming languages and
development environments.[21] Web programming language Opa also has built-in

3. support for MongoDB, which is tightly integrated in the language and offers a
type-safety layer on top of MongoDB.[22] There are also a large number of
unofficial or community-supported drivers for other programming languages and
frameworks.[21]
Management and graphical front-ends[edit]
MongoDB tools[edit]
In a MongoDB installation the following commands are available:
mongo
MongoDB offers an interactive shell called mongo,[23] which lets developers
view, insert, remove, and update data in their databases, as well as get
replication information, set up sharding, shut down servers, execute JavaScript,
and more.
Administrative information can also be accessed through a web interface,[24] a
simple webpage that serves information about the current server status. By
default, this interface is 1000 ports above the database port (28017).
mongostat
mongostat[25] is a command-line tool that displays a summary list of status
statistics for a currently running MongoDB instance: how many inserts, updates,
removes, queries, and commands were performed, as well as what percentage of the
time the database was locked and how much memory it is using. This tool is
similar to the UNIX/Linux vmstat utility.
mongotop
mongotop[26] is a command-line tool providing a method to track the amount of
time a MongoDB instance spends reading and writing data. mongotop provides
statistics on the per-collection level. By default, mongotop returns values
every second. This tool is similar to the UNIX/Linux top utility.
mongosniff
mongosniff[27] is a command-line tool providing a low-level tracing/sniffing
view into database activity by monitoring (or "sniffing") network traffic going
to and from MongoDB. mongosniff requires the Libpcap network library and is only
available for Unix-like systems. A cross-platform alternative is the open source
Wireshark packet analyzer which has full support for the MongoDB wire protocol.
mongoimport, mongoexport
mongoimport[28] is a command-line utility to import content from a JSON, CSV, or
TSV export created by mongoexport[29] or potentially other third-party data
exports.
mongodump, mongorestore
mongodump[30] is a command-line utility for creating a binary export of the
contents of a Mongo database; mongorestore[31] can be used to reload a database
dump.
Production Deployments[edit]
Some of the prominent users of MongoDB include:[32]
MetLife uses MongoDB for “The Wall," a customer service application providing a
"360-degree view" of MetLife customers.[33]
Craigslist stores over 2 billion records in MongoDB.[34]
SAP uses MongoDB in the SAP PaaS.[35]
Forbes stores articles and companies data in MongoDB.[36]
The New York Times uses MongoDB in its form-building application for photo
submissions.[37]
Sourceforge uses MongoDB for its back-end storage pages.[38]
Codecademy[39]
Shutterfly uses MongoDB for its photo platform. As of 2013, the photo platform
stores 18 billion photos uploaded by Shutterfly's 7 million users.[40][41]
The Guardian uses MongoDB for its identity system.[42]
CERN uses MongoDB as the primary back-end for the Data Aggregation System for
the Large Hadron Collider.[43]
Foursquare deploys MongoDB on Amazon AWS to store venues and user check-ins into
venues.[44]
eBay uses MongoDB in the search suggestion and the internal Cloud Manager State
Hub.[45]
See also[edit]

4. Portal icon Free software portal
Apache's Erlang-based CouchDB (open source)
Apache's Cassandra (open source)
Apache's Java-based HBase and Accumulo (open source)
Basho Riak (open source, Apache License 2.0)
TokuMX performance engine for MongoDB (open source)
Apache's Java-based ElasticSearch (open source)
References[edit]
Jump up ^ "10gen embraces what it created, becomes MongoDB Inc.". Gigaom.
Retrieved 27 August 2013.
Jump up ^ "DB-Engines Ranking". Retrieved 8 September 2013.
Jump up ^ MongoDB daddy: My baby beats Google BigTable
^ Jump up to: a b The MongoDB NoSQL Database Blog, The AGPL
Jump up ^ The MongoDB NoSQL Database Blog, MongoDB 1.4 Ready for Production
Jump up ^ MongoDB Support by 10gen
Jump up ^ MongoDB Developer Manual
Jump up ^ [1]
Jump up ^ [2]
Jump up ^ GridFS article on MongoDB Developer's Manual
Jump up ^ NGINX plugin for MongoDB source code
Jump up ^ lighttpd plugin for MongoDB source code
Jump up ^ FAQ: Concurrency
Jump up ^ FAQ Concurrency - How Granular Are Locks
Jump up ^ FAQ Concurrency - How Does Sharding Affect Concurrency
Jump up ^ FAQ Concurrency - Do Operations Ever Yield the Lock
Jump up ^ 32-bit Limitations
Jump up ^ Does Everybody Hate MongoDB
Jump up ^ What is the Working Set
Jump up ^ Optimizing Your MongoDB Dataset
^ Jump up to: a b "MongoDB Drivers and Client Libraries “ MongoDB Ecosystem
2.2.2". Mongodb.org. Retrieved 2013-07-08.
Jump up ^ / (2012-11-27). "The database · MLstate/opalang Wiki · GitHub".
Github.com. Retrieved 2013-07-08.
Jump up ^ mongo - The Interactive Shell
Jump up ^ HTTP Console
Jump up ^ mongostat Manual
Jump up ^ mongotop Manual
Jump up ^ mongosniff Manual
Jump up ^ mongoimport Manual
Jump up ^ mongoexport Manual
Jump up ^ mongodump Manual
Jump up ^ mongorestore Manual
Jump up ^ Production Deployments
Jump up ^ MetLife Uses NoSQL For Customer Service Breakthrough
Jump up ^ Lessons Learned from Migrating 2+ Billion Documents at Craigslist
Jump up ^ The Quest to Understand the Use of MongoDB in the SAP PaaS
Jump up ^ Supporting Distributed Global Workforce of Contributors with MongoDB
Jump up ^ NYT + MongoDB in Production
Jump up ^ Scaling SourceForge with MongoDB
Jump up ^ How Codeacademy is Using MongoDB
Jump up ^ Real World NoSQL: MongoDB at Shutterfly
Jump up ^ Here's How We Think Of Shutterfly's Stock Value
Jump up ^ MongoDB at The Guardian
Jump up ^ Holy Large Hadron Collider, Batman!
Jump up ^ Experiences Deploying MongoDB on AWS
Jump up ^ MongoDB at eBay
Bibliography[edit]
Banker, Kyle (March 28, 2011), MongoDB in Action (1st ed.), Manning, p. 375,
ISBN 978-1-935182-87-0
Chodorow, Kristina; Dirolf, Michael (September 23, 2010), MongoDB: The
Definitive Guide (1st ed.), O'Reilly Media, p. 216, ISBN 978-1-4493-8156-1
Pirtle, Mitch (March 3, 2011), MongoDB for Web Development (1st ed.), Addison-

5. Wesley Professional, p. 360, ISBN 978-0-321-70533-4
Hawkins, Tim; Plugge, Eelco; Membrey, Peter (September 26, 2010), The Definitive
Guide to MongoDB: The NoSQL Database for Cloud and Desktop Computing (1st ed.),
Apress, p. 350, ISBN 978-1-4302-3051-9
External links[edit]
Official website
MongoDB Manual
Designing for the Cloud at MIT Technology Review
A vendor-independent comparison of NoSQL databases: Cassandra, HBase, MongoDB,
Riak (NetworkWorld)
Categories: Free database management systemsDocument-oriented
databasesDistributed computing architectureStructured storageNoSQL
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This page was last modified on 12 December 2013 at 18:05.
Text is available under the Creative Commons Attribution-ShareAlike License;
additional terms may apply. By using this site, you agree to the Terms of Use
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6. Wesley Professional, p. 360, ISBN 978-0-321-70533-4
Hawkins, Tim; Plugge, Eelco; Membrey, Peter (September 26, 2010), The Definitive
Guide to MongoDB: The NoSQL Database for Cloud and Desktop Computing (1st ed.),
Apress, p. 350, ISBN 978-1-4302-3051-9
External links[edit]
Official website
MongoDB Manual
Designing for the Cloud at MIT Technology Review
A vendor-independent comparison of NoSQL databases: Cassandra, HBase, MongoDB,
Riak (NetworkWorld)
Categories: Free database management systemsDocument-oriented
databasesDistributed computing architectureStructured storageNoSQL
Navigation menu
Create accountLog inArticleTalkReadEditView history
Search
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
Print/export
Languages
???????
?????????
Català
Deutsch
Español
?????
Français
???
???????
Bahasa Indonesia
Italiano
Magyar
Nederlands
???
Polski
Português
???????
?????
Türkçe
??????????
??
Edit links
This page was last modified on 12 December 2013 at 18:05.
Text is available under the Creative Commons Attribution-ShareAlike License;
additional terms may apply. By using this site, you agree to the Terms of Use
and Privacy Policy.
Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a nonprofit organization.
Privacy policyAbout WikipediaDisclaimersContact WikipediaDevelopersMobile
viewWikimedia Foundation Powered by MediaWiki