hbgstc123 commented on code in PR #9660: URL: https://github.com/apache/paimon/pull/9660#discussion_r3999735269
########## paimon-core/src/main/java/org/apache/paimon/stats/SimpleStatsMerger.java: ########## @@ -0,0 +1,176 @@ +/* + * 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.paimon.stats; + +import org.apache.paimon.data.BinaryArray; +import org.apache.paimon.data.GenericRow; +import org.apache.paimon.data.InternalArray; +import org.apache.paimon.data.InternalRow; +import org.apache.paimon.data.serializer.InternalRowSerializer; +import org.apache.paimon.io.DataFileMeta; +import org.apache.paimon.types.DataType; +import org.apache.paimon.types.RowType; + +import javax.annotation.Nullable; + +import java.util.ArrayList; +import java.util.List; + +import static org.apache.paimon.stats.SimpleStats.EMPTY_STATS; + +/** Utility to merge {@link SimpleStats} from multiple files with the same stats schema. */ +public class SimpleStatsMerger { + + private SimpleStatsMerger() {} + + public static SimpleStats merge(List<SimpleStats> statsList, RowType rowType) { + return merge(statsList, rowType, null); + } + + public static SimpleStats merge( + List<SimpleStats> statsList, RowType rowType, @Nullable List<String> valueStatsCols) { + if (statsList.isEmpty()) { + return EMPTY_STATS; + } + + RowType statsRowType = valueStatsCols == null ? rowType : rowType.project(valueStatsCols); + int fieldCount = statsRowType.getFieldCount(); + InternalRowSerializer serializer = new InternalRowSerializer(statsRowType); + InternalRow.FieldGetter[] fieldGetters = new InternalRow.FieldGetter[fieldCount]; + for (int i = 0; i < fieldCount; i++) { + DataType fieldType = statsRowType.getTypeAt(i); + fieldGetters[i] = InternalRow.createFieldGetter(fieldType, i); + } + + Object[] minValues = new Object[fieldCount]; + Object[] maxValues = new Object[fieldCount]; + long[] nullCounts = new long[fieldCount]; + boolean[] minUnknown = new boolean[fieldCount]; + boolean[] maxUnknown = new boolean[fieldCount]; + boolean[] nullCountUnknown = new boolean[fieldCount]; + boolean[] hasValue = new boolean[fieldCount]; + + for (SimpleStats stats : statsList) { + if (stats.equals(EMPTY_STATS)) { + continue; + } + InternalRow minRow = stats.minValues(); + InternalRow maxRow = stats.maxValues(); + InternalArray nullCountArray = stats.nullCounts(); + for (int i = 0; i < fieldCount; i++) { + if (minRow.isNullAt(i)) { + minUnknown[i] = true; + } else { + minValues[i] = pickMin(minValues[i], fieldGetters[i].getFieldOrNull(minRow)); + } + if (maxRow.isNullAt(i)) { + maxUnknown[i] = true; + } else { + maxValues[i] = pickMax(maxValues[i], fieldGetters[i].getFieldOrNull(maxRow)); + } + if (nullCountArray.isNullAt(i)) { + nullCountUnknown[i] = true; + } else { + nullCounts[i] += nullCountArray.getLong(i); + } + hasValue[i] = + hasValue[i] + || minUnknown[i] + || maxUnknown[i] + || nullCountUnknown[i] + || !minRow.isNullAt(i) + || !maxRow.isNullAt(i) + || !nullCountArray.isNullAt(i); + } + } + + boolean allEmpty = true; + for (boolean value : hasValue) { + if (value) { + allEmpty = false; + break; + } + } + if (allEmpty) { + return EMPTY_STATS; + } + + Object[] mergedMinValues = new Object[fieldCount]; + Object[] mergedMaxValues = new Object[fieldCount]; + Long[] nullCountObjects = new Long[fieldCount]; + for (int i = 0; i < fieldCount; i++) { + mergedMinValues[i] = minUnknown[i] ? null : minValues[i]; + mergedMaxValues[i] = maxUnknown[i] ? null : maxValues[i]; + nullCountObjects[i] = nullCountUnknown[i] ? null : nullCounts[i]; + } + return new SimpleStats( + serializer.toBinaryRow(GenericRow.of(mergedMinValues)).copy(), + serializer.toBinaryRow(GenericRow.of(mergedMaxValues)).copy(), + BinaryArray.fromLongArray(nullCountObjects)); + } + + @Nullable + private static Object pickMin(@Nullable Object current, @Nullable Object candidate) { + if (candidate == null) { + return current; + } + if (current == null) { + return candidate; + } + if (current instanceof Comparable && candidate instanceof Comparable) { + Comparable<Object> currentComparable = (Comparable<Object>) current; + return currentComparable.compareTo(candidate) <= 0 ? current : candidate; + } + return current; + } + + @Nullable + private static Object pickMax(@Nullable Object current, @Nullable Object candidate) { + if (candidate == null) { + return current; + } + if (current == null) { + return candidate; + } + if (current instanceof Comparable && candidate instanceof Comparable) { + Comparable<Object> currentComparable = (Comparable<Object>) current; + return currentComparable.compareTo(candidate) >= 0 ? current : candidate; Review Comment: thanks for the review, fixed accordingly. -- This is an automated message from the Apache Git Service. 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