ACID (Atomicity, Consistency, Isolation, and Durability) is a long-expected Hive feature, and builds a foundation for relational databases; it has been available since Hive v0.14.0. Full ACID support in Hive is implemented through row-level transactions and locks. This makes it possible for Hive to deal with use cases such as concurrent read/write, data cleaning, data modification, complex ETL/SCD (Slow Changing Dimensions), streaming data ingest, bulk data merge, and so on. In this section, we'll introduce them in more detail.