What is constant folding in the context of query optimization?
| Term | Description |
|---|---|
| Constant Folding | Constant folding is an optimization technique used in query compilers, where compile-time evaluation of expressions that involve only constants is performed. This means that expressions like 2 * 3 are simplified to 6 during the compilation phase, rather than at runtime. The main advantage of constant folding is that it reduces the computational overhead during the execution of the query, making the process more efficient. In systems like Apache Spark’s Catalyst Optimizer, constant folding helps in creating a more streamlined and efficient execution plan by minimizing unnecessary calculations. |