参考链接
- https://mp.weixin.qq.com/s/pfe5AJI4TnPdyFRLbqwF4A
SparkStrategies
SparkStrategies包含了一系列特定的Strategies,这些Strategies是继承自QueryPlanner中定义的Strategy,它定义接受一个Logical Plan,生成一系列的Physical Plan
通过Strategies把逻辑计划转换成可以具体执行的物理计划
package object sql {
/**
* Converts a logical plan into zero or more SparkPlans. This API is exposed for experimenting
* with the query planner and is not designed to be stable across spark releases. Developers
* writing libraries should instead consider using the stable APIs provided in
* [[org.apache.spark.sql.sources]]