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Posted to commits@pinot.apache.org by "chiquelo (via GitHub)" <gi...@apache.org> on 2023/04/26 22:25:16 UTC
[GitHub] [pinot] chiquelo commented on a diff in pull request #10643: Add PercentileKLL aggregation function
chiquelo commented on code in PR #10643:
URL: https://github.com/apache/pinot/pull/10643#discussion_r1178263145
##########
pinot-core/src/main/java/org/apache/pinot/core/common/ObjectSerDeUtils.java:
##########
@@ -918,6 +923,26 @@ public Sketch deserialize(ByteBuffer byteBuffer) {
}
};
+ public static final ObjectSerDe<KllSketch> KLL_SKETCH_SER_DE = new ObjectSerDe<KllSketch>() {
Review Comment:
This should be written as KLL_DOUBLE_SKETCH_SER_DE
##########
pinot-core/src/main/java/org/apache/pinot/core/query/aggregation/function/PercentileKLLAggregationFunction.java:
##########
@@ -0,0 +1,248 @@
+/**
+ * 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.pinot.core.query.aggregation.function;
+
+import com.google.common.base.Preconditions;
+import java.util.List;
+import java.util.Map;
+import org.apache.datasketches.kll.KllDoublesSketch;
+import org.apache.datasketches.memory.Memory;
+import org.apache.pinot.common.request.context.ExpressionContext;
+import org.apache.pinot.common.utils.DataSchema.ColumnDataType;
+import org.apache.pinot.core.common.BlockValSet;
+import org.apache.pinot.core.query.aggregation.AggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.ObjectAggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.GroupByResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.ObjectGroupByResultHolder;
+import org.apache.pinot.segment.spi.AggregationFunctionType;
+import org.apache.pinot.spi.data.FieldSpec.DataType;
+
+/**
+ * <p>
+ * {@code PercentileKLLAggregationFunction} provides an approximate percentile calculator using the KLL algorithm
+ * from <a href="https://datasketches.apache.org/docs/KLL/KLLSketch.html">Apache DataSketches library</a>.
+ * </p>
+ * <p>
+ * The interface is similar to plain 'Percentile' function except for the optional K value which determines
+ * the size, hence the accuracy of the sketch.
+ * </p>
+ * <p><b>PERCENTILE_KLL(col, percentile, kValue)</b></p>
+ * <p>E.g.:</p>
+ * <ul>
+ * <li><b>PERCENTILE_KLL(col, 90)</b></li>
+ * <li><b>PERCENTILE_KLL(col, 99.9, 800)</b></li>
+ * </ul>
+ *
+ * <p>
+ * There is a variation of the function (<b>PERCENTILE_RAW_KLL</b>) that returns the Base64 encoded
+ * sketch object to be used externally.
+ * </p>
+ */
+public class PercentileKLLAggregationFunction
+ extends BaseSingleInputAggregationFunction<KllDoublesSketch, Comparable> {
+
+ protected final double _percentile;
+ protected int _kValue = 200; // size of the sketch. This is the default size used by DataSketches lib as well
+
+ public PercentileKLLAggregationFunction(List<ExpressionContext> arguments) {
+ super(arguments.get(0));
+
+ // Check that there are correct number of arguments
+ int numArguments = arguments.size();
+ Preconditions.checkArgument(numArguments == 2 || numArguments == 3,
+ "Expecting 2 or 3 arguments for PercentileKLL function: "
+ + "PERCENTILE_KLL(column, percentile, k=200");
+
+ _percentile = arguments.get(1).getLiteral().getDoubleValue();
Review Comment:
Is there any check that this argument is between 0 and 100?
##########
pinot-core/src/main/java/org/apache/pinot/core/query/aggregation/function/PercentileKLLAggregationFunction.java:
##########
@@ -0,0 +1,248 @@
+/**
+ * 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.pinot.core.query.aggregation.function;
+
+import com.google.common.base.Preconditions;
+import java.util.List;
+import java.util.Map;
+import org.apache.datasketches.kll.KllDoublesSketch;
+import org.apache.datasketches.memory.Memory;
+import org.apache.pinot.common.request.context.ExpressionContext;
+import org.apache.pinot.common.utils.DataSchema.ColumnDataType;
+import org.apache.pinot.core.common.BlockValSet;
+import org.apache.pinot.core.query.aggregation.AggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.ObjectAggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.GroupByResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.ObjectGroupByResultHolder;
+import org.apache.pinot.segment.spi.AggregationFunctionType;
+import org.apache.pinot.spi.data.FieldSpec.DataType;
+
+/**
+ * <p>
+ * {@code PercentileKLLAggregationFunction} provides an approximate percentile calculator using the KLL algorithm
+ * from <a href="https://datasketches.apache.org/docs/KLL/KLLSketch.html">Apache DataSketches library</a>.
+ * </p>
+ * <p>
+ * The interface is similar to plain 'Percentile' function except for the optional K value which determines
+ * the size, hence the accuracy of the sketch.
+ * </p>
+ * <p><b>PERCENTILE_KLL(col, percentile, kValue)</b></p>
+ * <p>E.g.:</p>
+ * <ul>
+ * <li><b>PERCENTILE_KLL(col, 90)</b></li>
+ * <li><b>PERCENTILE_KLL(col, 99.9, 800)</b></li>
+ * </ul>
+ *
+ * <p>
+ * There is a variation of the function (<b>PERCENTILE_RAW_KLL</b>) that returns the Base64 encoded
+ * sketch object to be used externally.
+ * </p>
+ */
+public class PercentileKLLAggregationFunction
+ extends BaseSingleInputAggregationFunction<KllDoublesSketch, Comparable> {
+
+ protected final double _percentile;
+ protected int _kValue = 200; // size of the sketch. This is the default size used by DataSketches lib as well
+
+ public PercentileKLLAggregationFunction(List<ExpressionContext> arguments) {
+ super(arguments.get(0));
+
+ // Check that there are correct number of arguments
+ int numArguments = arguments.size();
+ Preconditions.checkArgument(numArguments == 2 || numArguments == 3,
+ "Expecting 2 or 3 arguments for PercentileKLL function: "
+ + "PERCENTILE_KLL(column, percentile, k=200");
+
+ _percentile = arguments.get(1).getLiteral().getDoubleValue();
+ if (numArguments == 3) {
+ _kValue = arguments.get(2).getLiteral().getIntValue();
Review Comment:
A similar check should be done on the K value. There's could be some memory implications from setting the K to be too high: https://datasketches.apache.org/docs/KLL/KLLAccuracyAndSize.html
##########
pinot-segment-local/src/main/java/org/apache/pinot/segment/local/customobject/SerializedKLL.java:
##########
@@ -0,0 +1,49 @@
+/**
+ * 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.pinot.segment.local.customobject;
+
+import java.util.Base64;
+import org.apache.datasketches.kll.KllDoublesSketch;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+/**
+ * Serialized and comparable version of KllDoublesSketch.
+ * Compares two sketches for a specific percentile value.
+ */
+public class SerializedKLL implements Comparable<SerializedKLL> {
+ private final double _quantile;
+ private final KllDoublesSketch _sketch;
+
+ public SerializedKLL(KllDoublesSketch sketch, double percentile) {
+ _sketch = sketch;
+ _quantile = percentile / 100.0;
+ }
+
+ @Override
+ public int compareTo(SerializedKLL other) {
+ checkArgument(other._quantile == _quantile, "Quantile numbers don't matchå");
Review Comment:
Is this character intended?
##########
pinot-segment-spi/src/main/java/org/apache/pinot/segment/spi/AggregationFunctionType.java:
##########
@@ -142,6 +146,10 @@ public static AggregationFunctionType getAggregationFunctionType(String function
return PERCENTILETDIGEST;
} else if (remainingFunctionName.equals("RAWTDIGEST") || remainingFunctionName.matches("RAWTDIGEST\\d+")) {
return PERCENTILERAWTDIGEST;
+ } else if (remainingFunctionName.equals("KLL") || remainingFunctionName.matches("KLL\\d+")) {
+ return PERCENTILETDIGEST;
Review Comment:
This seems like an error
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