Spark2 之 FallBack

newValidator

src/main/scala/org/apache/gluten/extension/columnar/validator/Validators.scala

  /**
   * A validator that doesn't involve native validation.
   *
   * This is typically RAS planner that does native validation inline without relying on tags. Thus,
   * validator `#fallbackByNativeValidation` is not required. See
   * [[org.apache.gluten.extension.columnar.enumerated.RasOffload]].
   *
   * This could also be used in legacy planner for doing trivial offload without the help of rewrite
   * rules.
   */
  def newValidator(conf: GlutenConfig): Validator = {
    Validator
      .builder()
      .fallbackByHint()
      .fallbackIfScanOnlyWithFilterPushed(conf.enableScanOnly)
      .fallbackComplexExpressions()