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h1. Apache Hive

The {tm}[Apache Hive|http://hive.apache.org]{tm} data warehouse software facilitates querying and managing large datasets residing in distributed storage.  Built on top of {tm}[Apache Hadoop|http://hadoop.apache.org]{tm}, it provides
* Tools to enable easy data extract/transform/load (ETL)
* A mechanism to impose structure on a variety of data formats
* Access to files stored either directly in {tm}Apache HDFS{tm} or in other data storage systems such as {tm}Apache HBase{tm}
* Query execution via MapReduce

Hive defines a simple SQL-like query language, called QL, that enables users familiar with SQL to query the data. At the same time, this language also allows programmers who are familiar with the MapReduce framework to be able to plug in their custom mappers and reducers to perform more sophisticated analysis that may not be supported by the built-in capabilities of the language.  QL can also be extended with custom scalar functions (UDF's), aggregations (UDAF's), and table functions (UDTF's).

Hive does not mandate read or written data be in the "Hive format"---there is no such thing. Hive works equally well on Thrift, control delimited, or your specialized data formats.  Please see [File Format|DeveloperGuide#File_Formats] and [SerDe|http://www.slideshare.net/ragho/hive-user-meeting-august-2009-facebook] in the [Developer Guide|DeveloperGuide] for details.

Hive is not designed for OLTP workloads and does not offer real-time queries or row-level updates. It is best used for batch jobs over large sets of append-only data (like web logs). What Hive values most are scalability (scale out with more machines added dynamically to the Hadoop cluster), extensibility (with MapReduce framework and UDF/UDAF/UDTF), fault-tolerance, and loose-coupling with its input formats.

Components of Hive include HcatalogHCatalog and WebhcatWebHCat. *[Hcatalog|Hive:HCatalog]* is a component of hiveHive. It is a table and storage management layer for Hadoop that enables users with different data processing tools — including Pig and MapReduce — to more easily read and write data on the grid.

*[WebHcatWebHCat|Hive:WebHCat]* provicesprovides a service that you can use to run Hadoop MapReduce (or YARN), Pig, Hive jobs or perform Hive metadata operations, using a HTTP (REST style) interface. 

h1. General Information about Hive

* [Getting Started|GettingStarted]
* [Presentations and Papers about Hive|Presentations]
* [A List of Sites and Applications Powered by Hive|PoweredBy]
* [FAQ|User FAQ]
* [hive-users Mailing List|http://hive.apache.org/mailing_lists.html#Users]
* Hive IRC Channel: {{\#hive}} on irc.freenode.net
* [About This Wiki|AboutThisWiki]

h1. User Documentation

* [Hive Tutorial|Tutorial]
* [HiveQL Language Manual|LanguageManual] ([Queries|LanguageManual Select], [DML|LanguageManual DML], [DDL|LanguageManual DDL], [CLI|LanguageManual Cli], etc.)
* [Hive Operators and Functions|OperatorsAndFunctions]
* [Hive Web Interface|HiveWebInterface]
* [Hive Client|HiveClient] ([JDBC|HiveClient#JDBC], [ODBC|HiveClient#ODBC], [Thrift|HiveClient#Thrift Java Client], etc.)
* [HiveServer2 Client|HiveServer2 Clients]
* [Hive Change Log|HiveChangeLog]
* [Avro SerDe|AvroSerDe]

h1. Administrator Documentation

* [Installing Hive|AdminManual Installation]
* [Configuring Hive|AdminManual Configuration]
* [Setting Up Metastore|AdminManual MetastoreAdmin]
* [Setting Up Hive Web Interface|HiveWebInterface]
* [Setting Up Hive Server|AdminManual SettingUpHiveServer] ([JDBC|HiveJDBCInterface], [ODBC|HiveODBC], [Thrift|HiveServer], [HiveServer2|Setting up HiveServer2])
* [Hive on Amazon Web Services|HiveAws]
* [Hive on Amazon Elastic MapReduce|HiveAmazonElasticMapReduce]

h1. HCatalog and WebHCat Documentation

* [HCatalog|HCatalog]
* [WebHCat (Templeton)|WebHCat]

h1. Resources for Contributors

* [Hive Developer FAQ|HiveDeveloperFAQ]
* [How to Contribute|HowToContribute]
* [Hive Contributors Meetings|Development ContributorsMeetings]
* [Hive Developer Guide|DeveloperGuide]
* [Plugin Developer Kit|PluginDeveloperKit]
* [Unit Test Parallel Execution]
* [Hive PTest2 Infrastructure]
* [Hive PreCommit Patch Testing]
* [Hive Performance|Performance]
* [Hive Architecture Overview|Design]
* [Hive Design Docs|DesignDocs]
* [Roadmap/Call to Add More Features|Roadmap]
* [Full-Text Search over All Hive Resources|http://search-hadoop.com/Hive]
* [How to edit the website]
* [Becoming a Committer|BecomingACommitter]
* [How to Commit|HowToCommit]
* [How to Release|HowToRelease]
* [Build Status on Jenkins (Formerly Hudson)|HudsonBuild]
* [Project Bylaws|Bylaws]

For more information, please see the official [Hive website|http://hive.apache.org].

_Apache Hive, Apache Hadoop, Apache HBase, Apache HDFS, Apache, the Apache feather logo, and the Apache Hive project logo are trademarks of The Apache Software Foundation._