Github user rxin commented on a diff in the pull request:
https://github.com/apache/spark/pull/6356#discussion_r35024822
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/SparkPlanner.scala ---
@@ -0,0 +1,93 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql.execution
+
+import org.apache.spark.SparkContext
+import org.apache.spark.annotation.Experimental
+import org.apache.spark.sql._
+import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.execution.TakeOrderedAndProject
+import org.apache.spark.sql.sources.DataSourceStrategy
+
+@Experimental
+class SparkPlanner(val sqlContext: SQLContext) extends
org.apache.spark.sql.execution.SparkStrategies {
+ val sparkContext: SparkContext = sqlContext.sparkContext
+
+ def codegenEnabled: Boolean = sqlContext.conf.codegenEnabled
+
+ def unsafeEnabled: Boolean = sqlContext.conf.unsafeEnabled
+
+ def numPartitions: Int = sqlContext.conf.numShufflePartitions
+
+ def strategies: Seq[Strategy] =
+ sqlContext.experimental.extraStrategies ++ (
+ DataSourceStrategy ::
+ DDLStrategy ::
+ TakeOrderedAndProject ::
+ HashAggregation ::
+ LeftSemiJoin ::
+ HashJoin ::
+ InMemoryScans ::
+ ParquetOperations ::
+ BasicOperators ::
+ CartesianProduct ::
+ BroadcastNestedLoopJoin :: Nil)
+
+ /**
+ * 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 `prunePushedDownFilters` parameter is used to remove those
filters that can be optimized
+ * away by the filter pushdown optimization.
+ *
+ * The required attributes for both filtering and expression evaluation
are passed to the
+ * provided `scanBuilder` function so that it can avoid unnecessary
column materialization.
+ */
+ def pruneFilterProject(
+ projectList: Seq[NamedExpression],
+ filterPredicates: Seq[Expression],
+ prunePushedDownFilters: Seq[Expression] =>
Seq[Expression],
+ scanBuilder: Seq[Attribute] => SparkPlan):
SparkPlan = {
+
+ val projectSet = AttributeSet(projectList.flatMap(_.references))
+ val filterSet = AttributeSet(filterPredicates.flatMap(_.references))
+ val filterCondition =
+
prunePushedDownFilters(filterPredicates).reduceLeftOption(catalyst.expressions.And)
+
+ // Right now we still use a projection even if the only evaluation is
applying an alias
+ // to a column. Since this is a no-op, it could be avoided. However,
using this
+ // optimization with the current implementation would change the
output schema.
+ // TODO: Decouple final output schema from expression evaluation so
this copy can be
+ // avoided safely.
+
+ if (AttributeSet(projectList.map(_.toAttribute)) == projectSet &&
+ filterSet.subsetOf(projectSet)) {
+ // When it is possible to just use column pruning to get the right
projection and
+ // when the columns of this projection are enough to evaluate all
filter conditions,
+ // just do a scan followed by a filter, with no extra project.
+ val scan = scanBuilder(projectList.asInstanceOf[Seq[Attribute]])
+ filterCondition.map(Filter(_, scan)).getOrElse(scan)
+ } else {
+ val scan = scanBuilder((projectSet ++ filterSet).toSeq)
+ Project(projectList, filterCondition.map(Filter(_,
scan)).getOrElse(scan))
+ }
+ }
+}
--- End diff --
i think u need to add a new line here to not fail scalastyle
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