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| = Introduction |
| |
| Ignite 3 introduces new SQL engine based on the Apache Calcite framework to parse and optimize queries and generate execution plans. Previously, it was based on H2 Database. |
| |
| Apache Calcite is a dynamic data management framework, which mainly serves for mediating between applications and one or more data storage locations and data processing engines. |
| For more information on Apache Calcite, please see the link:https://calcite.apache.org/docs/[product documentation,window=_blank]. |
| |
| Replacing H2 SQL engine with Apache Calcite incorporates the following general improvements: |
| |
| * *Wider SQL support*: Apache Calcite, unlike H2, is specifically designed for SQL enablement on top of an arbitrary external data storage; |
| * *Better optimization algorithms*: Apache Calcite optimizes queries by repeatedly applying planner rules to a relational expression; |
| * *Higher overall performance*: Calcite offers much higher levels of execution flexibility, as well as higher efficiency in terms of both memory and CPU consumption. |
