clintropolis commented on a change in pull request #6768: extension for exactly distinct count for single long type dimension:accurate-cardinality URL: https://github.com/apache/incubator-druid/pull/6768#discussion_r254124223
########## File path: extensions-contrib/accurate-cardinality/src/main/java/org/apache/druid/query/aggregation/cardinality/accurate/AccurateCardinalityAggregatorFactory.java ########## @@ -0,0 +1,264 @@ +/* + * 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.druid.query.aggregation.cardinality.accurate; + +import com.fasterxml.jackson.annotation.JsonCreator; +import com.fasterxml.jackson.annotation.JsonProperty; +import com.google.common.base.Function; +import com.google.common.base.Objects; +import com.google.common.collect.ImmutableList; +import com.google.common.collect.Lists; +import org.apache.commons.codec.binary.Base64; +import org.apache.druid.java.util.common.StringUtils; +import org.apache.druid.query.ColumnSelectorPlus; +import org.apache.druid.query.aggregation.Aggregator; +import org.apache.druid.query.aggregation.AggregatorFactory; +import org.apache.druid.query.aggregation.AggregatorUtil; +import org.apache.druid.query.aggregation.BufferAggregator; +import org.apache.druid.query.aggregation.NoopAggregator; +import org.apache.druid.query.aggregation.NoopBufferAggregator; +import org.apache.druid.query.aggregation.cardinality.accurate.collector.Collector; +import org.apache.druid.query.aggregation.cardinality.accurate.collector.CollectorFactory; +import org.apache.druid.query.aggregation.cardinality.accurate.collector.RoaringBitmapCollectorFactory; +import org.apache.druid.query.aggregation.cardinality.accurate.types.AccurateCardinalityAggregatorColumnSelectorStrategy; +import org.apache.druid.query.aggregation.cardinality.accurate.types.AccurateCardinalityAggregatorColumnSelectorStrategyFactory; +import org.apache.druid.query.dimension.DefaultDimensionSpec; +import org.apache.druid.query.dimension.DimensionSpec; +import org.apache.druid.segment.ColumnSelectorFactory; +import org.apache.druid.segment.DimensionHandlerUtils; +import org.apache.druid.segment.column.ValueType; + +import java.nio.ByteBuffer; +import java.util.Comparator; +import java.util.List; + + +public class AccurateCardinalityAggregatorFactory extends AggregatorFactory +{ + private static final AccurateCardinalityAggregatorColumnSelectorStrategyFactory STRATEGY_FACTORY = + new AccurateCardinalityAggregatorColumnSelectorStrategyFactory(); + + private static final CollectorFactory DEFAULT_BITMAP_FACTORY = new RoaringBitmapCollectorFactory(); + + private final String name; + private final DimensionSpec field; + private final CollectorFactory collectorFactory; + + @JsonCreator + public AccurateCardinalityAggregatorFactory( + @JsonProperty("name") String name, + @JsonProperty("field") final DimensionSpec field, + @JsonProperty("collectorFactory") CollectorFactory collectorFactory + ) + { + this.name = name; + this.field = field; + this.collectorFactory = collectorFactory == null ? DEFAULT_BITMAP_FACTORY : collectorFactory; + } + + public AccurateCardinalityAggregatorFactory( + String name, + DimensionSpec field + ) + { + this(name, field, DEFAULT_BITMAP_FACTORY); + } + + public AccurateCardinalityAggregatorFactory( + String name, + String field, + CollectorFactory collectorFactory + ) + { + this(name, new DefaultDimensionSpec(field, field, ValueType.LONG), collectorFactory); + } + + @JsonProperty + public DimensionSpec getField() + { + return field; + } + + @JsonProperty + public CollectorFactory getCollectorFactory() + { + return collectorFactory; + } + + @Override + public Aggregator factorize(ColumnSelectorFactory columnFactory) + { + ColumnSelectorPlus<AccurateCardinalityAggregatorColumnSelectorStrategy> selectorPlus = DimensionHandlerUtils.createColumnSelectorPlus( + STRATEGY_FACTORY, + field, + columnFactory + ); + if (selectorPlus == null) { + return NoopAggregator.instance(); + } + return new AccurateCardinalityAggregator(name, selectorPlus, collectorFactory.makeEmptyCollector()); + } + + @Override + public BufferAggregator factorizeBuffered(ColumnSelectorFactory columnFactory) + { + ColumnSelectorPlus<AccurateCardinalityAggregatorColumnSelectorStrategy> selectorPlus = DimensionHandlerUtils.createColumnSelectorPlus( + STRATEGY_FACTORY, + field, + columnFactory + ); + if (selectorPlus == null) { + return NoopBufferAggregator.instance(); + } + return new AccurateCardinalityBufferAggregator(selectorPlus, collectorFactory); + } + + @Override + public Comparator getComparator() + { + return new Comparator<Collector>() + { + @Override + public int compare(Collector c1, Collector c2) + { + return c1.compareTo(c2); + } + }; + } + + @Override + public Object combine(Object lhs, Object rhs) + { + if (rhs == null) { + return lhs; + } + if (lhs == null) { + return rhs; + } + Collector lhsCollector = (Collector) lhs; + return lhsCollector.fold((Collector) rhs); + } + + @Override + public AggregatorFactory getCombiningFactory() + { + return new BitmapAggregatorFactory(name, name); + } + + @Override + public List<AggregatorFactory> getRequiredColumns() + { + return Lists.transform( + ImmutableList.of(field), + new Function<DimensionSpec, AggregatorFactory>() + { + @Override + public AggregatorFactory apply(DimensionSpec input) + { + return new AccurateCardinalityAggregatorFactory(input.getOutputName(), input, collectorFactory); + } + } + ); + } + + @Override + public Object deserialize(Object object) + { + final ByteBuffer buffer; + + if (object instanceof byte[]) { + buffer = ByteBuffer.wrap((byte[]) object); + } else if (object instanceof ByteBuffer) { + // Be conservative, don't assume we own this buffer. + buffer = ((ByteBuffer) object).duplicate(); + } else if (object instanceof String) { + buffer = ByteBuffer.wrap(Base64.decodeBase64(StringUtils.toUtf8((String) object))); + } else { + return object; + } + return collectorFactory.makeCollector(buffer); + } + + @Override + public Object finalizeComputation(Object object) + { + if (object == null) { + return 0; + } + return ((Collector) object).getCardinality(); + } + + @JsonProperty + @Override + public String getName() + { + return name; + } + + @Override + public List<String> requiredFields() + { + return ImmutableList.of(field.getOutputName()); + } + + @Override + public String getTypeName() + { + return AccurateCardinalityModule.BITMAP_COLLECTOR; + } + + @Override + public int getMaxIntermediateSize() + { + return 1024; Review comment: Where did this number come from? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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