spark-reviews mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From mallman <...@git.apache.org>
Subject [GitHub] spark pull request #16578: [SPARK-4502][SQL] Parquet nested column pruning
Date Fri, 03 Nov 2017 06:52:09 GMT
Github user mallman commented on a diff in the pull request:

    https://github.com/apache/spark/pull/16578#discussion_r148717122
  
    --- Diff: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/JoinFieldExtractionPushdown.scala
---
    @@ -0,0 +1,66 @@
    +/*
    + * 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.catalyst.optimizer
    +
    +import org.apache.spark.sql.catalyst.expressions.{Attribute, AttributeSet, NamedExpression}
    +import org.apache.spark.sql.catalyst.planning.PhysicalOperation
    +import org.apache.spark.sql.catalyst.plans.logical.{Join, LogicalPlan, Project}
    +
    +/**
    + * Pushes down aliases to [[expressions.GetStructField]] expressions in a projection
over a join
    + * and its join condition. The original [[expressions.GetStructField]] expressions are
replaced
    + * with references to the pushed down aliases.
    + */
    +object JoinFieldExtractionPushdown extends FieldExtractionPushdown {
    +  override def apply(plan: LogicalPlan): LogicalPlan =
    +    plan transformDown {
    +      case op @ PhysicalOperation(projects, Seq(),
    +          join @ Join(left, right, joinType, Some(joinCondition))) =>
    +        val fieldExtractors = (projects :+ joinCondition).flatMap(getFieldExtractors).distinct
    +
    +        if (fieldExtractors.nonEmpty) {
    +          val (aliases, substituteAttributes) = constructAliasesAndSubstitutions(fieldExtractors)
    +
    +          // Construct the new projections and join condition by substituting each GetStructField
    +          // expression with a reference to its alias
    +          val newProjects =
    +            projects.map(substituteAttributes).collect { case named: NamedExpression
=> named }
    --- End diff --
    
    Please see my reply to the same question for `AggregateFieldExtractionPushdown`.


---

---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org
For additional commands, e-mail: reviews-help@spark.apache.org


Mime
View raw message