Documentation for Hive can be found in wiki docs and javadocs.
Javadocs describe the Hive API.
Note These javadocs are for Hive in HDP-2.1.2, which contains important bug fixes. Hortonworks strongly recommends upgrading to HDP-2.1.2.
The Hive wiki is organized in four major sections:
General Information about Hive
User Documentation
Administrator Documentation
Resources for Contributors