rohangarg commented on code in PR #13819: URL: https://github.com/apache/druid/pull/13819#discussion_r1116742868
########## extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/tuple/ArrayOfDoublesSketchConstantPostAggregator.java: ########## @@ -0,0 +1,151 @@ +/* + * 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.datasketches.tuple; + +import com.fasterxml.jackson.annotation.JsonCreator; +import com.fasterxml.jackson.annotation.JsonProperty; +import com.google.common.base.Preconditions; +import org.apache.commons.codec.digest.DigestUtils; +import org.apache.datasketches.tuple.arrayofdoubles.ArrayOfDoublesSketch; +import org.apache.datasketches.tuple.arrayofdoubles.ArrayOfDoublesSketches; +import org.apache.druid.java.util.common.StringUtils; +import org.apache.druid.java.util.common.guava.Comparators; +import org.apache.druid.query.aggregation.AggregatorFactory; +import org.apache.druid.query.aggregation.AggregatorUtil; +import org.apache.druid.query.cache.CacheKeyBuilder; +import org.apache.druid.segment.data.SafeWritableMemory; + +import java.util.Collections; +import java.util.Comparator; +import java.util.Map; +import java.util.Set; + +/** + * This post-aggregator converts a given Base64 encoded string to an ArrayOfDoublesSketch. + * The input column contains name of post-aggregator output and base64 encoded input string. + * The output is a deserialized {@link ArrayOfDoublesSketch} . + */ +public class ArrayOfDoublesSketchConstantPostAggregator extends ArrayOfDoublesSketchPostAggregator +{ + + private final String value; + private final ArrayOfDoublesSketch sketchValue; + + @JsonCreator + public ArrayOfDoublesSketchConstantPostAggregator(@JsonProperty("name") String name, @JsonProperty("value") String value) + { + super(name); + Preconditions.checkArgument(value != null && !value.isEmpty(), + "Constant value cannot be null or empty, expecting base64 encoded sketch string"); + this.value = value; + this.sketchValue = deserializeFromBase64EncodedStringSafe(value); + } + + private ArrayOfDoublesSketch deserializeFromBase64EncodedStringSafe(final String str) Review Comment: can this be re-used from `ArrayOfDoublesSketchOperations` ? ########## extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/tuple/ArrayOfDoublesSketchToEncodedStringPostAggregator.java: ########## @@ -0,0 +1,79 @@ +/* + * 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.datasketches.tuple; + +import com.fasterxml.jackson.annotation.JsonCreator; +import com.fasterxml.jackson.annotation.JsonProperty; +import org.apache.datasketches.tuple.arrayofdoubles.ArrayOfDoublesSketch; +import org.apache.druid.java.util.common.IAE; +import org.apache.druid.query.aggregation.AggregatorUtil; +import org.apache.druid.query.aggregation.PostAggregator; +import org.apache.druid.query.cache.CacheKeyBuilder; +import org.apache.druid.segment.ColumnInspector; +import org.apache.druid.segment.column.ColumnType; + +import java.util.Base64; +import java.util.Comparator; +import java.util.Map; + +/** + * Returns a base64 encoded string of a given {@link ArrayOfDoublesSketch}. + * This is a string returned by encoding the output of toByteArray() using Base64 method of the sketch. + * This can be useful for debugging and using the sketch output in other operations. + */ +public class ArrayOfDoublesSketchToEncodedStringPostAggregator extends ArrayOfDoublesSketchUnaryPostAggregator +{ + + @JsonCreator + public ArrayOfDoublesSketchToEncodedStringPostAggregator( + @JsonProperty("name") final String name, + @JsonProperty("field") final PostAggregator field + ) + { + super(name, field); + } + + @Override + public String compute(final Map<String, Object> combinedAggregators) + { + final ArrayOfDoublesSketch sketch = (ArrayOfDoublesSketch) getField().compute(combinedAggregators); + return Base64.getEncoder().encodeToString(sketch.toByteArray()); Review Comment: there's already a utility method in `StringUtils` class to do base64 encoding of a string - that can be re-used here. ########## extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/tuple/ArrayOfDoublesSketchToMetricsEstimatePostAggregator.java: ########## @@ -0,0 +1,91 @@ +/* + * 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.datasketches.tuple; + +import com.fasterxml.jackson.annotation.JsonCreator; +import com.fasterxml.jackson.annotation.JsonProperty; +import org.apache.commons.math3.stat.descriptive.SummaryStatistics; +import org.apache.datasketches.tuple.arrayofdoubles.ArrayOfDoublesSketch; +import org.apache.datasketches.tuple.arrayofdoubles.ArrayOfDoublesSketchIterator; +import org.apache.druid.java.util.common.IAE; +import org.apache.druid.query.aggregation.AggregatorUtil; +import org.apache.druid.query.aggregation.PostAggregator; +import org.apache.druid.query.cache.CacheKeyBuilder; +import org.apache.druid.segment.ColumnInspector; +import org.apache.druid.segment.column.ColumnType; + +import java.util.Arrays; +import java.util.Comparator; +import java.util.Map; + +/** + * Returns a list of estimate values of metrics column from a given {@link ArrayOfDoublesSketch}. + * The result will be N double values, where N is the number of double values kept in the sketch per key. + */ +public class ArrayOfDoublesSketchToMetricsEstimatePostAggregator extends ArrayOfDoublesSketchUnaryPostAggregator +{ + + @JsonCreator + public ArrayOfDoublesSketchToMetricsEstimatePostAggregator( + @JsonProperty("name") final String name, + @JsonProperty("field") final PostAggregator field + ) + { + super(name, field); + } + + @Override + public double[] compute(final Map<String, Object> combinedAggregators) + { + final ArrayOfDoublesSketch sketch = (ArrayOfDoublesSketch) getField().compute(combinedAggregators); + final SummaryStatistics[] stats = new SummaryStatistics[sketch.getNumValues()]; + Arrays.setAll(stats, i -> new SummaryStatistics()); + final ArrayOfDoublesSketchIterator it = sketch.iterator(); + while (it.next()) { + final double[] values = it.getValues(); + for (int i = 0; i < values.length; i++) { + stats[i].addValue(values[i]); + } + } + final double[] estimates = new double[sketch.getNumValues()]; + Arrays.setAll(estimates, i -> ((stats[i].getMean()) * (sketch.getRetainedEntries())) / (sketch.getTheta())); Review Comment: could this be just `stats[i].getSum() / sketch.getTheta()`? ########## extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/tuple/ArrayOfDoublesSketchToEncodedStringPostAggregator.java: ########## @@ -0,0 +1,79 @@ +/* + * 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.datasketches.tuple; + +import com.fasterxml.jackson.annotation.JsonCreator; +import com.fasterxml.jackson.annotation.JsonProperty; +import org.apache.datasketches.tuple.arrayofdoubles.ArrayOfDoublesSketch; +import org.apache.druid.java.util.common.IAE; +import org.apache.druid.query.aggregation.AggregatorUtil; +import org.apache.druid.query.aggregation.PostAggregator; +import org.apache.druid.query.cache.CacheKeyBuilder; +import org.apache.druid.segment.ColumnInspector; +import org.apache.druid.segment.column.ColumnType; + +import java.util.Base64; +import java.util.Comparator; +import java.util.Map; + +/** + * Returns a base64 encoded string of a given {@link ArrayOfDoublesSketch}. + * This is a string returned by encoding the output of toByteArray() using Base64 method of the sketch. + * This can be useful for debugging and using the sketch output in other operations. + */ +public class ArrayOfDoublesSketchToEncodedStringPostAggregator extends ArrayOfDoublesSketchUnaryPostAggregator Review Comment: name could be `ArrayOfDoublesSketchToBase64StringPostAggregator` for clarity -- This is an automated message from the Apache Git Service. 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