bruno-roustant commented on a change in pull request #1395: SOLR-14365: CollapsingQParser - Avoiding always allocate int[] and float[] with size equals to number of unique values (WIP) URL: https://github.com/apache/lucene-solr/pull/1395#discussion_r405478717
########## File path: solr/core/src/java/org/apache/solr/util/numeric/IntFloatDynamicMap.java ########## @@ -0,0 +1,115 @@ +/* + * 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.solr.util.numeric; + +import java.util.Arrays; + +import com.carrotsearch.hppc.IntFloatHashMap; +import com.carrotsearch.hppc.cursors.FloatCursor; +import com.carrotsearch.hppc.procedures.IntFloatProcedure; +import org.apache.lucene.util.ArrayUtil; + +import static org.apache.solr.util.numeric.DynamicMap.mapExpectedElements; +import static org.apache.solr.util.numeric.DynamicMap.threshold; +import static org.apache.solr.util.numeric.DynamicMap.useArrayBased; + +public class IntFloatDynamicMap { + private int maxSize; + private IntFloatHashMap hashMap; + private float[] keyValues; + private float emptyValue; + private int threshold; + + public IntFloatDynamicMap(int expectedMaxSize, float emptyValue) { + this.threshold = threshold(expectedMaxSize); + this.maxSize = expectedMaxSize; + this.emptyValue = emptyValue; + if (useArrayBased(expectedMaxSize)) { + upgradeToArray(); + } else { + this.hashMap = new IntFloatHashMap(mapExpectedElements(expectedMaxSize)); + } + } + + private void upgradeToArray() { + keyValues = new float[maxSize]; + if (emptyValue != 0.0f) { + Arrays.fill(keyValues, emptyValue); + } + if (hashMap != null) { + hashMap.forEach((IntFloatProcedure) (key, value) -> keyValues[key] = value); + hashMap = null; + } + } + + private void growBuffer(int minSize) { + assert keyValues != null; + int size = keyValues.length; + keyValues = ArrayUtil.grow(keyValues, minSize); + if (emptyValue != 0.0f) { + for (int i = size; i < keyValues.length; i++) { + keyValues[i] = emptyValue; + } + } + } + + + public void set(int key, float value) { + if (keyValues != null) { + if (key >= keyValues.length) { + growBuffer(key + 1); + } + keyValues[key] = value; + } else { + this.hashMap.put(key, value); + this.maxSize = Math.max(key, maxSize); + if (this.hashMap.size() > threshold) { Review comment: Did you test and debug when the DynamicMap upgrades from a map to an array internally? I mean in debug mode step by step here. I think the map first enlarges and rehashes just before the upgrade to an array. Let's take an example with expectedKeyMax = 500K. this.threshold = threshold(expectedKeyMax) = 500000/64 = 7812 IntFloatHashMap initial capacity = mapExpectedElements(expectedKeyMax) = (int) (threshold(expectedKeyMax) / 0.75f) = (int) (7812 / 0.75f) = 10416 IntFloatHashMap internal threshold = ceil(initial capacity * 0.75) = ceil(10416 * 0.75) = 7812 Internally the HPPC map enlarges during a put() when its size == 7812 *before* incrementing the size. Here the condition to upgrade to an array triggers when the map size *after* the put is > 7812, so at 7813. So I think the map first enlarges and rehashes just before we upgrade to an array, which would be wasteful. Also, the map internal threshold is ceil(initial capacity * 0.75), but it could be without ceil() for other implementations. To be safe wrt the float rounding, I suggested to add +1 in DynamicMap. mapExpectedElements(int), but it is probably better to be safe here. ---------------------------------------------------------------- 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: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
