Bikas Saha and Saumitra Buragohain share some of the direction the Apache Hive team is going in version 3:
The latest release of Apache Hive 3 (part of HDP 3) provides significant new capabilities including ACID support for data ingest. This functionality has many applications, a crucial one being privacy support for data modifications and deletions for GDPR. In addition, ACID also significantly reduces the time to ingest for data, thereby improving data freshness for Hive queries. To provide these features, Hive needs to take full control of the files that store the table data and thus this data is no longer directly accessible by third party systems like Apache Spark. Thus Apache Spark’s built-in support for Hive table data is no longer supported for data managed by Hive 3.
At the same time, Apache Spark has become the de-facto standard for a wide variety complex processing use cases on Big Data. This includes data stored in Hive 3 tables and thus we need a way to provide efficient, high-performance, ACID compliant access to Hive 3 table data from Spark. Fortunately, Apache Spark supports a pluggable approach for various data sources and Apache Hive itself can also be considered as one data source. We have implemented the Hive Warehouse Connector (HWC) as library to provide first class support for Spark to read Hive 3 data for subsequent complex processing (like machine learning) in Spark.
Spark is also commonly used to ETL raw data into Hive tables and this scenario should continue to be supported in the Hive ACID world. To do that, HWC integrates with the latest Hive Streaming APIs to support ingest into Hive both from batch jobs as well as structured streaming jobs.
Overall the Hive Warehouse connector provide efficient read write access to Hive warehouse data from Spark jobs, while providing transparent user identity propagation and maintaining consistent security and access control.
Spark has had some dependencies on Hive (or at least expectations of certain Hive conventions like /tmp/hive existing), but the two systems have historically been more (friendly) competitors than tools integrated in the same chain.