The document details the features and improvements of Hortonworks Data Platform (HDP) 2.1, with a focus on Apache Hive for interactive SQL querying in Hadoop. It outlines enhancements such as vectorized query execution, expanded SQL compliance, new data types, and features to improve performance. Additionally, it highlights the Stinger initiative aimed at supporting interactive workloads and the introduction of over 10 new SQL features in Hive.