| /* |
| * 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.drill.metastore.statistics; |
| |
| import org.apache.drill.metastore.metadata.BaseMetadata; |
| |
| import java.util.List; |
| |
| /** |
| * Implementation of {@link CollectableColumnStatisticsKind} which contain base |
| * column statistics kinds with implemented {@code mergeStatistics()} method. |
| */ |
| public class ColumnStatisticsKind<T> extends BaseStatisticsKind<T> implements CollectableColumnStatisticsKind<T> { |
| |
| /** |
| * Column statistics kind which represents nulls count for the specific column. |
| */ |
| public static final ColumnStatisticsKind<Long> NULLS_COUNT = |
| new ColumnStatisticsKind<Long>(ExactStatisticsConstants.NULLS_COUNT, true) { |
| @Override |
| public Long mergeStatistics(List<? extends ColumnStatistics> statisticsList) { |
| long nullsCount = 0; |
| for (ColumnStatistics<?> statistics : statisticsList) { |
| Long statNullsCount = statistics.get(this); |
| if (statNullsCount == null || statNullsCount == Statistic.NO_COLUMN_STATS) { |
| return Statistic.NO_COLUMN_STATS; |
| } else { |
| nullsCount += statNullsCount; |
| } |
| } |
| return nullsCount; |
| } |
| |
| @Override |
| public Long getFrom(ColumnStatistics metadata) { |
| Long rowCount = super.getFrom(metadata); |
| return rowCount != null ? rowCount : Statistic.NO_COLUMN_STATS; |
| } |
| }; |
| |
| /** |
| * Column statistics kind which represents min value of the specific column. |
| */ |
| public static final ColumnStatisticsKind<Object> MIN_VALUE = |
| new ColumnStatisticsKind<Object>(ExactStatisticsConstants.MIN_VALUE, true) { |
| @Override |
| @SuppressWarnings("unchecked") |
| public Object mergeStatistics(List<? extends ColumnStatistics> statisticsList) { |
| Object minValue = null; |
| for (ColumnStatistics statistics : statisticsList) { |
| Object statMinValue = getValueStatistic(statistics); |
| if (statMinValue != null && (statistics.getValueComparator().compare(minValue, statMinValue) > 0 || minValue == null)) { |
| minValue = statMinValue; |
| } |
| } |
| return minValue; |
| } |
| }; |
| |
| /** |
| * Column statistics kind which represents max value of the specific column. |
| */ |
| public static final ColumnStatisticsKind<Object> MAX_VALUE = |
| new ColumnStatisticsKind<Object>(ExactStatisticsConstants.MAX_VALUE, true) { |
| @Override |
| @SuppressWarnings("unchecked") |
| public Object mergeStatistics(List<? extends ColumnStatistics> statisticsList) { |
| Object maxValue = null; |
| for (ColumnStatistics statistics : statisticsList) { |
| Object statMaxValue = getValueStatistic(statistics); |
| if (statMaxValue != null && statistics.getValueComparator().compare(maxValue, statMaxValue) < 0) { |
| maxValue = statMaxValue; |
| } |
| } |
| return maxValue; |
| } |
| }; |
| |
| /** |
| * Column statistics kind which represents exact number of non-null values for the specific column. |
| */ |
| public static final ColumnStatisticsKind<Long> NON_NULL_VALUES_COUNT = |
| new ColumnStatisticsKind<Long>(ExactStatisticsConstants.NON_NULL_VALUES_COUNT, true) { |
| @Override |
| public Long mergeStatistics(List<? extends ColumnStatistics> statisticsList) { |
| long nonNullRowCount = 0; |
| for (ColumnStatistics<?> statistics : statisticsList) { |
| Long nnRowCount = statistics.get(this); |
| if (nnRowCount != null) { |
| nonNullRowCount += nnRowCount; |
| } |
| } |
| return nonNullRowCount; |
| } |
| }; |
| |
| /** |
| * Column statistics kind which represents estimated number of non-null values for the specific column. |
| */ |
| public static final ColumnStatisticsKind<Double> NON_NULL_COUNT = |
| new ColumnStatisticsKind<Double>(Statistic.NNROWCOUNT, false) { |
| @Override |
| public Double mergeStatistics(List<? extends ColumnStatistics> statisticsList) { |
| double nonNullRowCount = 0; |
| for (ColumnStatistics<?> statistics : statisticsList) { |
| Double nnRowCount = statistics.get(this); |
| if (nnRowCount != null) { |
| nonNullRowCount += nnRowCount; |
| } |
| } |
| return nonNullRowCount; |
| } |
| }; |
| |
| /** |
| * Column statistics kind which represents total row count for the specific column. |
| */ |
| public static final ColumnStatisticsKind<Double> ROWCOUNT = |
| new ColumnStatisticsKind<Double>(Statistic.ROWCOUNT, false) { |
| @Override |
| public Double mergeStatistics(List<? extends ColumnStatistics> statisticsList) { |
| double rowCount = 0; |
| for (ColumnStatistics<?> statistics : statisticsList) { |
| Double count = getFrom(statistics); |
| if (count != null) { |
| rowCount += count; |
| } |
| } |
| return rowCount; |
| } |
| }; |
| |
| /** |
| * Column statistics kind which represents number of distinct values for the specific column. |
| */ |
| public static final ColumnStatisticsKind<Double> NDV = |
| new ColumnStatisticsKind<>(Statistic.NDV, false); |
| |
| /** |
| * Column statistics kind which is the width of the specific column. |
| */ |
| public static final ColumnStatisticsKind AVG_WIDTH = |
| new ColumnStatisticsKind(Statistic.AVG_WIDTH, false); |
| |
| /** |
| * Column statistics kind which is the histogram of the specific column. |
| */ |
| public static final ColumnStatisticsKind<Histogram> HISTOGRAM = |
| new ColumnStatisticsKind<>("histogram", false); |
| |
| ColumnStatisticsKind(String statisticKey, boolean exact) { |
| super(statisticKey, exact); |
| } |
| |
| /** |
| * Returns value which corresponds to this statistic kind, |
| * obtained from specified {@link BaseMetadata}. |
| * |
| * @param metadata the source of statistic value |
| * @return value which corresponds to this statistic kind |
| */ |
| public T getFrom(ColumnStatistics<?> metadata) { |
| return metadata.get(this); |
| } |
| |
| @SuppressWarnings("unchecked") |
| public <V> V getValueStatistic(ColumnStatistics<V> metadata) { |
| return (V) metadata.get(this); |
| } |
| |
| @Override |
| public T mergeStatistics(List<? extends ColumnStatistics> statistics) { |
| throw new UnsupportedOperationException("Cannot merge statistics for " + statisticKey); |
| } |
| } |