| /* |
| * 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.iceberg; |
| |
| import java.util.List; |
| import org.apache.iceberg.expressions.Expressions; |
| import org.apache.iceberg.transforms.PartitionSpecVisitor; |
| |
| public class Partitioning { |
| private Partitioning() { |
| } |
| |
| /** |
| * Check whether the spec contains a bucketed partition field. |
| * |
| * @param spec a partition spec |
| * @return true if the spec has field with a bucket transform |
| */ |
| public static boolean hasBucketField(PartitionSpec spec) { |
| List<Boolean> bucketList = PartitionSpecVisitor.visit(spec, new PartitionSpecVisitor<Boolean>() { |
| @Override |
| public Boolean identity(int fieldId, String sourceName, int sourceId) { |
| return false; |
| } |
| |
| @Override |
| public Boolean bucket(int fieldId, String sourceName, int sourceId, int width) { |
| return true; |
| } |
| |
| @Override |
| public Boolean truncate(int fieldId, String sourceName, int sourceId, int width) { |
| return false; |
| } |
| |
| @Override |
| public Boolean year(int fieldId, String sourceName, int sourceId) { |
| return false; |
| } |
| |
| @Override |
| public Boolean month(int fieldId, String sourceName, int sourceId) { |
| return false; |
| } |
| |
| @Override |
| public Boolean day(int fieldId, String sourceName, int sourceId) { |
| return false; |
| } |
| |
| @Override |
| public Boolean hour(int fieldId, String sourceName, int sourceId) { |
| return false; |
| } |
| |
| @Override |
| public Boolean alwaysNull(int fieldId, String sourceName, int sourceId) { |
| return false; |
| } |
| |
| @Override |
| public Boolean unknown(int fieldId, String sourceName, int sourceId, String transform) { |
| return false; |
| } |
| }); |
| |
| return bucketList.stream().anyMatch(Boolean::booleanValue); |
| } |
| |
| /** |
| * Create a sort order that will group data for a partition spec. |
| * <p> |
| * If the partition spec contains bucket columns, the sort order will also have a field to sort by a column that is |
| * bucketed in the spec. The column is selected by the highest number of buckets in the transform. |
| * |
| * @param spec a partition spec |
| * @return a sort order that will cluster data for the spec |
| */ |
| public static SortOrder sortOrderFor(PartitionSpec spec) { |
| if (spec.isUnpartitioned()) { |
| return SortOrder.unsorted(); |
| } |
| |
| SortOrder.Builder builder = SortOrder.builderFor(spec.schema()); |
| SpecToOrderVisitor converter = new SpecToOrderVisitor(builder); |
| PartitionSpecVisitor.visit(spec, converter); |
| |
| // columns used for bucketing are high cardinality; add one to the sort at the end |
| String bucketColumn = converter.bucketColumn(); |
| if (bucketColumn != null) { |
| builder.asc(bucketColumn); |
| } |
| |
| return builder.build(); |
| } |
| |
| private static class SpecToOrderVisitor implements PartitionSpecVisitor<Void> { |
| private final SortOrder.Builder builder; |
| private String bucketColumn = null; |
| private int highestNumBuckets = 0; |
| |
| private SpecToOrderVisitor(SortOrder.Builder builder) { |
| this.builder = builder; |
| } |
| |
| String bucketColumn() { |
| return bucketColumn; |
| } |
| |
| @Override |
| public Void identity(int fieldId, String sourceName, int sourceId) { |
| builder.asc(sourceName); |
| return null; |
| } |
| |
| @Override |
| public Void bucket(int fieldId, String sourceName, int sourceId, int numBuckets) { |
| // the column with highest cardinality is usually the one with the highest number of buckets |
| if (numBuckets > highestNumBuckets) { |
| this.highestNumBuckets = numBuckets; |
| this.bucketColumn = sourceName; |
| } |
| builder.asc(Expressions.bucket(sourceName, numBuckets)); |
| return null; |
| } |
| |
| @Override |
| public Void truncate(int fieldId, String sourceName, int sourceId, int width) { |
| builder.asc(Expressions.truncate(sourceName, width)); |
| return null; |
| } |
| |
| @Override |
| public Void year(int fieldId, String sourceName, int sourceId) { |
| builder.asc(Expressions.year(sourceName)); |
| return null; |
| } |
| |
| @Override |
| public Void month(int fieldId, String sourceName, int sourceId) { |
| builder.asc(Expressions.month(sourceName)); |
| return null; |
| } |
| |
| @Override |
| public Void day(int fieldId, String sourceName, int sourceId) { |
| builder.asc(Expressions.day(sourceName)); |
| return null; |
| } |
| |
| @Override |
| public Void hour(int fieldId, String sourceName, int sourceId) { |
| builder.asc(Expressions.hour(sourceName)); |
| return null; |
| } |
| |
| @Override |
| public Void alwaysNull(int fieldId, String sourceName, int sourceId) { |
| // do nothing for alwaysNull, it doesn't need to be added to the sort |
| return null; |
| } |
| } |
| } |