cloud-fan commented on code in PR #38799: URL: https://github.com/apache/spark/pull/38799#discussion_r1042277374
########## sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/InsertWindowGroupLimit.scala: ########## @@ -0,0 +1,98 @@ +/* + * 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.{Alias, Attribute, CurrentRow, DenseRank, EqualTo, Expression, GreaterThan, GreaterThanOrEqual, IntegerLiteral, LessThan, LessThanOrEqual, NamedExpression, PredicateHelper, Rank, RowFrame, RowNumber, SpecifiedWindowFrame, UnboundedPreceding, WindowExpression, WindowSpecDefinition} +import org.apache.spark.sql.catalyst.plans.logical.{Filter, LocalRelation, LogicalPlan, Window, WindowGroupLimit} +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.catalyst.trees.TreePattern.{FILTER, WINDOW} + +/** + * Optimize the filter based on rank-like window function by reduce not required rows. + * This rule optimizes the following cases: + * {{{ + * SELECT *, ROW_NUMBER() OVER(PARTITION BY k ORDER BY a) AS rn FROM Tab1 WHERE rn = 5 + * SELECT *, ROW_NUMBER() OVER(PARTITION BY k ORDER BY a) AS rn FROM Tab1 WHERE 5 = rn + * SELECT *, ROW_NUMBER() OVER(PARTITION BY k ORDER BY a) AS rn FROM Tab1 WHERE rn < 5 + * SELECT *, ROW_NUMBER() OVER(PARTITION BY k ORDER BY a) AS rn FROM Tab1 WHERE 5 > rn + * SELECT *, ROW_NUMBER() OVER(PARTITION BY k ORDER BY a) AS rn FROM Tab1 WHERE rn <= 5 + * SELECT *, ROW_NUMBER() OVER(PARTITION BY k ORDER BY a) AS rn FROM Tab1 WHERE 5 >= rn + * }}} + */ +object InsertWindowGroupLimit extends Rule[LogicalPlan] with PredicateHelper { + + /** + * Extract all the limit values from predicates. + */ + def extractLimits(condition: Expression, attr: Attribute): Option[Int] = { + val limits = splitConjunctivePredicates(condition).collect { + case EqualTo(IntegerLiteral(limit), e) if e.semanticEquals(attr) => limit + case EqualTo(e, IntegerLiteral(limit)) if e.semanticEquals(attr) => limit + case LessThan(e, IntegerLiteral(limit)) if e.semanticEquals(attr) => limit - 1 + case GreaterThan(IntegerLiteral(limit), e) if e.semanticEquals(attr) => limit - 1 + case LessThanOrEqual(e, IntegerLiteral(limit)) if e.semanticEquals(attr) => limit + case GreaterThanOrEqual(IntegerLiteral(limit), e) if e.semanticEquals(attr) => limit + } + + if (limits.nonEmpty) Some(limits.min) else None + } + + private def supports( + windowExpressions: Seq[NamedExpression]): Boolean = windowExpressions.exists { + case Alias(WindowExpression(_: Rank | _: DenseRank | _: RowNumber, WindowSpecDefinition(_, _, + SpecifiedWindowFrame(RowFrame, UnboundedPreceding, CurrentRow))), _) => true + case _ => false + } + + def apply(plan: LogicalPlan): LogicalPlan = { + if (conf.windowGroupLimitThreshold == -1) return plan + + plan.transformWithPruning( + _.containsAllPatterns(FILTER, WINDOW), ruleId) { + case filter @ Filter(condition, + window @ Window(windowExpressions, partitionSpec, orderSpec, child)) + if !child.isInstanceOf[WindowGroupLimit] && !child.isInstanceOf[Window] && + supports(windowExpressions) && orderSpec.nonEmpty => + val limits = windowExpressions.collect { + case alias @ Alias(WindowExpression(rankLikeFunction, _), _) => + extractLimits(condition, alias.toAttribute).map((_, rankLikeFunction)) + }.filter(_.isDefined) + + // multiple different rank-like functions unsupported. + if (limits.isEmpty || limits.groupBy(_.get._2).size > 1) { Review Comment: We should use `ExpressionSet` to check semantically equals expressions, not just `groupBy` -- 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. To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org
