Apache Calcite is an open source framework for building databases and data management systems. It includes a SQL parser, an API for building expressions in relational algebra, and a query planning engine. As a framework, Calcite does not store its own data or metadata, but instead allows external data and metadata to be accessed by means of plug-ins.
Several other Apache projects use Calcite. Hive uses Calcite for cost-based query optimization;Julian Hyde. "Cost-based query optimization in Apache Hive 0.14", Hortonworks, 24 September 2014. Drill and Kylin use Calcite for SQL parsing and optimization; Samza and Storm use Calcite for streaming SQL. , Apex, Phoenix and Flink have projects under development that use Calcite.
References