HeartSaVioR commented on a change in pull request #31987: URL: https://github.com/apache/spark/pull/31987#discussion_r656886604
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/aggregate/MergingSessionsExec.scala ########## @@ -0,0 +1,126 @@ +/* + * 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.aggregate + +import org.apache.spark.rdd.RDD +import org.apache.spark.sql.catalyst.InternalRow +import org.apache.spark.sql.catalyst.expressions.{Ascending, Attribute, AttributeSet, Expression, MutableProjection, NamedExpression, SortOrder, UnsafeRow} +import org.apache.spark.sql.catalyst.expressions.aggregate.AggregateExpression +import org.apache.spark.sql.catalyst.plans.physical._ +import org.apache.spark.sql.execution.{SparkPlan, UnaryExecNode} +import org.apache.spark.sql.execution.metric.SQLMetrics + +/** + * This node is a variant of SortAggregateExec which merges the session windows based on the fact + * child node will provide inputs as sorted by group keys + the start time of session window. + * + * When merging windows, it also applies aggregations on merged window, which eliminates the + * necessity on buffering inputs (which requires copying rows) and update the session spec + * for each input. + * + * This class receives requiredChildDistribution from caller, to enable merging session in + * local partition before shuffling. Specifying both parameters to None won't trigger shuffle, + * but sort would still happen per local partition. + * + * Refer [[MergingSessionsIterator]] for more details. + */ +case class MergingSessionsExec( + requiredChildDistributionExpressions: Option[Seq[Expression]], + requiredChildDistributionOption: Option[Seq[Distribution]], + groupingExpressions: Seq[NamedExpression], + sessionExpression: NamedExpression, + aggregateExpressions: Seq[AggregateExpression], + aggregateAttributes: Seq[Attribute], + initialInputBufferOffset: Int, + resultExpressions: Seq[NamedExpression], + child: SparkPlan) extends UnaryExecNode { Review comment: Let's do it as it doesn't look to break the new tests. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
