Apache Calcite

Apache Calcite
Developer(s)	Apache Software Foundation
Initial release	June 27, 2014; 11 years ago (2014-06-27)[1]
Stable release	1.37.0 (May 6, 2024; 15 months ago (2024-05-06)[2]) [±]
Repository	Calcite Repository
Written in	Java
Operating system	Cross-platform
Platform	Java
Type	SQL database framework
License	Apache License 2.0
Website	calcite.apache.org

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.^[3] Hive uses Calcite for cost-based query optimization;^[4] Drill and Kylin use Calcite for SQL parsing and optimization; Samza and Storm use Calcite for streaming SQL. As of August 2016^[update], Apex, Phoenix and Flink have projects under development that use Calcite.