Github user kanzhang commented on a diff in the pull request:
https://github.com/apache/spark/pull/448#discussion_r11800221
--- Diff: sql/core/src/main/scala/org/apache/spark/sql/SchemaRDD.scala ---
@@ -313,4 +314,46 @@ class SchemaRDD(
}
}
}
+
+ /**
+ * Creates SchemaRDD by applying own schema to child RDD. Typically used
to wrap results of base
+ * RDD functions that do not change schema.
+ *
+ * @param childRDD RDD derived from this one and has same schema
+ *
+ * @group schema
+ */
+ private def applySchema(childRDD: RDD[Row]): SchemaRDD =
+ new SchemaRDD(sqlContext,
SparkLogicalPlan(ExistingRdd(logicalPlan.output, childRDD)))
+
+ //
=======================================================================
+ // Base RDD functions that do NOT change schema
+ //
=======================================================================
+
+ override def coalesce(numPartitions: Int, shuffle: Boolean = false):
SchemaRDD =
+ applySchema(super.coalesce(numPartitions, shuffle))
+
+ override def distinct(numPartitions: Int): SchemaRDD =
+ applySchema(super.distinct(numPartitions))
+
+ override def filter(f: Row => Boolean): SchemaRDD =
+ applySchema(super.filter(f))
+
+ override def intersection(other: RDD[Row]): SchemaRDD =
+ applySchema(super.intersection(other))
+
+ override def intersection(other: RDD[Row], partitioner: Partitioner):
SchemaRDD =
+ applySchema(super.intersection(other, partitioner))
+
+ override def intersection(other: RDD[Row], numPartitions: Int):
SchemaRDD =
+ applySchema(super.intersection(other, numPartitions))
+
+ override def sample(withReplacement: Boolean, fraction: Double, seed:
Int): SchemaRDD =
--- End diff --
Ah, I see the execution eventually calls the base method, so it is
equivalent?
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