mengw15 commented on code in PR #3774: URL: https://github.com/apache/texera/pull/3774#discussion_r2392945468
########## core/workflow-operator/src/main/scala/edu/uci/ics/amber/operator/stablemergesort/StableMergeSortOpExec.scala: ########## @@ -0,0 +1,156 @@ + +/* +* 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 edu.uci.ics.amber.operator.stablemergesort + +import edu.uci.ics.amber.core.executor.OperatorExecutor +import edu.uci.ics.amber.core.tuple.{AttributeType, Schema, Tuple, TupleLike} +import edu.uci.ics.amber.operator.stablemergesort.StableMergeSortOpDesc.StableSortKey +import edu.uci.ics.amber.util.JSONUtils.objectMapper + +import java.sql.Timestamp +import java.util.Locale +import scala.collection.mutable.ArrayBuffer +import scala.jdk.CollectionConverters._ + +class StableMergeSortOpExec(descString: String) extends OperatorExecutor { + + private val desc: StableMergeSortOpDesc = + objectMapper.readValue(descString, classOf[StableMergeSortOpDesc]) + + private val configuredKeys: List[StableSortKey] = desc.keys.asScala.toList + + private case class ResolvedKey( + index: Int, + attributeType: AttributeType, + descending: Boolean, + nullsFirst: Boolean + ) + + private var inputSchema: Schema = _ + private var resolved: Array[ResolvedKey] = _ + + // Incremental run stack: runs(level) holds a sorted run of size 2^level, or null if empty + private var runs: ArrayBuffer[ArrayBuffer[Tuple]] = _ + + override def open(): Unit = { + runs = ArrayBuffer.empty[ArrayBuffer[Tuple]] + } + + override def close(): Unit = { + if (runs != null) runs.clear() + } + + override def processTuple(tuple: Tuple, port: Int): Iterator[TupleLike] = { + if (inputSchema == null) { + inputSchema = tuple.getSchema + resolved = resolveKeys(inputSchema) + } + // each incoming tuple is a size-1 sorted run + val run = ArrayBuffer[Tuple](tuple) + pushRun(run) + Iterator.empty + } + + override def onFinish(port: Int): Iterator[TupleLike] = { + if (runs.isEmpty) return Iterator.empty + // fold-merge from left (earliest chunks) to right (latest), preserving chronology + var acc = runs(0) + var i = 1 + while (i < runs.length) { + acc = mergeRuns(acc, runs(i)) + i += 1 + } + acc.iterator + } + + private def resolveKeys(schema: Schema): Array[ResolvedKey] = { + configuredKeys.map { k => + val idx = schema.getIndex(k.attribute) + val at = schema.getAttribute(k.attribute).getType + val ord = Option(k.order).map(_.toLowerCase(Locale.ROOT)).getOrElse("asc") + val nul = Option(k.nulls).map(_.toLowerCase(Locale.ROOT)).getOrElse("last") + ResolvedKey( + index = idx, + attributeType = at, + descending = (ord == "desc"), + nullsFirst = (nul == "first") + ) + }.toArray + } + + + private def pushRun(initial: ArrayBuffer[Tuple]): Unit = { + // treat 'runs' as a chronological stack: append new run to end + runs.append(initial) + // while the top two runs have equal size, merge them into one (older run first) + while (runs.length >= 2 && runs(runs.length - 1).size == runs(runs.length - 2).size) { + val right = runs.remove(runs.length - 1) // newest + val left = runs.remove(runs.length - 1) // older + val merged = mergeRuns(left, right) // stable: left items come before right when equal + runs.append(merged) + } + } + + private def mergeRuns(left: ArrayBuffer[Tuple], right: ArrayBuffer[Tuple]): ArrayBuffer[Tuple] = { + val out = new ArrayBuffer[Tuple](left.size + right.size) + var i = 0 + var j = 0 + while (i < left.size && j < right.size) { + if (compareTuples(left(i), right(j)) <= 0) { + out += left(i); i += 1 + } else { + out += right(j); j += 1 + } + } + while (i < left.size) { out += left(i); i += 1 } + while (j < right.size) { out += right(j); j += 1 } + out + } + + private def compareTuples(a: Tuple, b: Tuple): Int = { Review Comment: The nulls are placed at first few rows, but I choose Nulls as last -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
