org.apache.spark.sql.SQLContext
Used to build table scan operators where complex projection and filtering are done using separate physical operators.
Used to build table scan operators where complex projection and filtering are done using separate physical operators. This function returns the given scan operator with Project and Filter nodes added only when needed. For example, a Project operator is only used when the final desired output requires complex expressions to be evaluated or when columns can be further eliminated out after filtering has been done.
The required attributes for both filtering and expression evaluation are passed to the
provided scanBuilder function so that it can avoid unnecessary column materialization.