cloud-fan commented on a change in pull request #27627: [WIP][SPARK-28067][SQL] Fix incorrect results for decimal aggregate sum by returning null on decimal overflow URL: https://github.com/apache/spark/pull/27627#discussion_r406019307
########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/DecimalSum.scala ########## @@ -0,0 +1,110 @@ +/* + * 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.expressions.aggregate + +import org.apache.spark.sql.catalyst.dsl.expressions._ +import org.apache.spark.sql.catalyst.expressions._ +import org.apache.spark.sql.internal.SQLConf +import org.apache.spark.sql.types._ + +case class DecimalSum(child: Expression) extends DeclarativeAggregate with ImplicitCastInputTypes { + + override def children: Seq[Expression] = child :: Nil + + override def nullable: Boolean = true + + // Return data type. + override def dataType: DataType = resultType + + override def inputTypes: Seq[AbstractDataType] = Seq(NumericType) + + private lazy val resultType = child.dataType match { + case DecimalType.Fixed(precision, scale) => + DecimalType.bounded(precision + 10, scale) + case _: IntegralType => LongType + case _ => DoubleType + } + + private lazy val sumDataType = resultType + + private lazy val sum = AttributeReference("sum", sumDataType)() + private lazy val overflow = AttributeReference("overflow", BooleanType, false)() + + private lazy val zero = Literal.default(resultType) + + override lazy val aggBufferAttributes = sum :: overflow :: Nil + + override lazy val initialValues: Seq[Expression] = Seq( + /* sum = */ Literal.create(null, sumDataType), + /* overflow = */ Literal.create(false, BooleanType) + ) + + override lazy val updateExpressions: Seq[Expression] = { + if (child.nullable) { + resultType match { + case d: DecimalType => + Seq( + If(overflow, Literal.create(null, sumDataType), coalesce( + CheckOverflow(coalesce(sum, zero) + child.cast(sumDataType), d, true), sum)), Review comment: I don't think we should check overflow at every step. For example, we may add a big value which makes the sum overflow, then add a big negative value and we are not overflow afer that. ---------------------------------------------------------------- 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: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org
