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The following commit(s) were added to refs/heads/master by this push:
new b542bb9 TDigest backed sketch aggregators (#7331)
b542bb9 is described below
commit b542bb9f341182c74733172b7d55d0c4e2a5a092
Author: Samarth Jain <[email protected]>
AuthorDate: Thu May 9 17:22:55 2019 -0700
TDigest backed sketch aggregators (#7331)
* First set of changes for tDigest histogram
* Add license
* Address code review comments
* Add a doc page for new T-Digest sketch aggregators. Minor code cleanup
and comments.
* Remove synchronization from BufferAggregators. Address code review
comments
* Fix typo
---
distribution/pom.xml | 4 +-
.../extensions-contrib/tdigestsketch-quantiles.md | 159 ++++++++
extensions-contrib/tdigestsketch/pom.xml | 94 +++++
.../TDigestBuildSketchAggregator.java | 93 +++++
.../TDigestBuildSketchAggregatorFactory.java | 268 ++++++++++++++
.../TDigestBuildSketchBufferAggregator.java | 121 +++++++
.../TDigestMergeSketchAggregator.java | 83 +++++
.../TDigestMergeSketchAggregatorFactory.java | 64 ++++
.../TDigestMergeSketchBufferAggregator.java | 110 ++++++
.../TDigestSketchComplexMetricSerde.java | 111 ++++++
.../tdigestsketch/TDigestSketchJsonSerializer.java | 41 +++
.../tdigestsketch/TDigestSketchModule.java | 76 ++++
.../tdigestsketch/TDigestSketchObjectStrategy.java | 63 ++++
.../TDigestSketchToQuantilesPostAggregator.java | 159 ++++++++
.../tdigestsketch/TDigestSketchUtils.java | 90 +++++
.../org.apache.druid.initialization.DruidModule | 16 +
.../tdigestsketch/GenerateTestData.java | 79 ++++
.../tdigestsketch/TDigestSketchAggregatorTest.java | 279 ++++++++++++++
.../src/test/resources/doubles_build_data.tsv | 400 +++++++++++++++++++++
.../src/test/resources/doubles_sketch_data.tsv | 20 ++
pom.xml | 1 +
.../druid/query/aggregation/AggregatorUtil.java | 5 +
22 files changed, 2335 insertions(+), 1 deletion(-)
diff --git a/distribution/pom.xml b/distribution/pom.xml
index a6f22f2..5c70eb2 100644
--- a/distribution/pom.xml
+++ b/distribution/pom.xml
@@ -334,7 +334,9 @@
<argument>-c</argument>
<argument>org.apache.druid.extensions.contrib:druid-virtual-columns</argument>
<argument>-c</argument>
-
<argument>org.apache.druid.extensions.contrib:druid-moving-average-query</argument>
</arguments>
+
<argument>org.apache.druid.extensions.contrib:druid-moving-average-query</argument>
+
<argument>org.apache.druid.extensions.contrib:druid-tdigestsketch</argument>
+ </arguments>
</configuration>
</execution>
</executions>
diff --git
a/docs/content/development/extensions-contrib/tdigestsketch-quantiles.md
b/docs/content/development/extensions-contrib/tdigestsketch-quantiles.md
new file mode 100644
index 0000000..9947e01
--- /dev/null
+++ b/docs/content/development/extensions-contrib/tdigestsketch-quantiles.md
@@ -0,0 +1,159 @@
+---
+layout: doc_page
+title: "T-Digest Quantiles Sketch module"
+---
+
+<!--
+ ~ 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.
+ -->
+
+# T-Digest Quantiles Sketch module
+
+This module provides Apache Druid (incubating) approximate sketch aggregators
based on T-Digest.
+T-Digest (https://github.com/tdunning/t-digest) is a popular datastructure for
accurate on-line accumulation of
+rank-based statistics such as quantiles and trimmed means.
+The datastructure is also designed for parallel programming use cases like
distributed aggregations or map reduce jobs by making combining two
intermediate t-digests easy and efficient.
+
+There are three flavors of T-Digest sketch aggregator available in Apache
Druid (incubating):
+
+1. buildTDigestSketch - used for building T-Digest sketches from raw numeric
values. It generally makes sense to
+use this aggregator when ingesting raw data into Druid. One can also use this
aggregator during query time too to
+generate sketches, just that one would be building these sketches on every
query execution instead of building them
+once during ingestion.
+2. mergeTDigestSketch - used for merging pre-built T-Digest sketches. This
aggregator is generally used during
+query time to combine sketches generated by buildTDigestSketch aggregator.
+3. quantilesFromTDigestSketch - used for generating quantiles from T-Digest
sketches. This aggregator is generally used
+during query time to generate quantiles from sketches built using the above
two sketch generating aggregators.
+
+To use this aggregator, make sure you
[include](../../operations/including-extensions.html) the extension in your
config file:
+
+```
+druid.extensions.loadList=["druid-tdigestsketch"]
+```
+
+### Aggregator
+
+The result of the aggregation is a T-Digest sketch that is built ingesting
numeric values from the raw data.
+
+```json
+{
+ "type" : "buildTDigestSketch",
+ "name" : <output_name>,
+ "fieldName" : <metric_name>,
+ "compression": <parameter that controls size and accuracy>
+ }
+```
+Example:
+```json
+{
+ "type": "buildTDigestSketch",
+ "name": "sketch",
+ "fieldName": "session_duration",
+ "compression": 200
+}
+```
+
+|property|description|required?|
+|--------|-----------|---------|
+|type|This String should always be "buildTDigestSketch"|yes|
+|name|A String for the output (result) name of the calculation.|yes|
+|fieldName|A String for the name of the input field containing raw numeric
values.|yes|
+|compression|Parameter that determines the accuracy and size of the sketch.
Higher compression means higher accuracy but more space to store sketches.|no,
defaults to 100|
+
+
+The result of the aggregation is a T-Digest sketch that is built by merging
pre-built T-Digest sketches.
+
+```json
+{
+ "type" : "mergeTDigestSketch",
+ "name" : <output_name>,
+ "fieldName" : <metric_name>,
+ "compression": <parameter that controls size and accuracy>
+ }
+```
+
+|property|description|required?|
+|--------|-----------|---------|
+|type|This String should always be "mergeTDigestSketch"|yes|
+|name|A String for the output (result) name of the calculation.|yes|
+|fieldName|A String for the name of the input field containing raw numeric
values.|yes|
+|compression|Parameter that determines the accuracy and size of the sketch.
Higher compression means higher accuracy but more space to store sketches.|no,
defaults to 100|
+
+Example:
+```json
+{
+ "queryType": "groupBy",
+ "dataSource": "test_datasource",
+ "granularity": "ALL",
+ "dimensions": [],
+ "aggregations": [{
+ "type": "mergeTDigestSketch",
+ "name": "merged_sketch",
+ "fieldName": "ingested_sketch",
+ "compression": 200
+ }],
+ "intervals": ["2016-01-01T00:00:00.000Z/2016-01-31T00:00:00.000Z"]
+}
+```
+### Post Aggregators
+
+#### Quantiles
+
+This returns an array of quantiles corresponding to a given array of fractions.
+
+```json
+{
+ "type" : "quantilesFromTDigestSketch",
+ "name": <output name>,
+ "field" : <post aggregator that refers to a TDigestSketch (fieldAccess or
another post aggregator)>,
+ "fractions" : <array of fractions>
+}
+```
+
+|property|description|required?|
+|--------|-----------|---------|
+|type|This String should always be "quantilesFromTDigestSketch"|yes|
+|name|A String for the output (result) name of the calculation.|yes|
+|fieldName|A String for the name of the input field containing raw numeric
values.|yes|
+|fractions|Non-empty array of fractions between 0 and 1|yes|
+
+Example:
+```json
+{
+ "queryType": "groupBy",
+ "dataSource": "test_datasource",
+ "granularity": "ALL",
+ "dimensions": [],
+ "aggregations": [{
+ "type": "mergeTDigestSketch",
+ "name": "merged_sketch",
+ "fieldName": "ingested_sketch",
+ "compression": 200
+ }],
+ "postAggregations": [{
+ "type": "quantilesFromTDigestSketch",
+ "name": "quantiles",
+ "fractions": [0, 0.5, 1],
+ "field": {
+ "type": "fieldAccess",
+ "fieldName": "merged_sketch"
+ }
+ }],
+ "intervals": ["2016-01-01T00:00:00.000Z/2016-01-31T00:00:00.000Z"]
+}
+```
diff --git a/extensions-contrib/tdigestsketch/pom.xml
b/extensions-contrib/tdigestsketch/pom.xml
new file mode 100644
index 0000000..f8c290c
--- /dev/null
+++ b/extensions-contrib/tdigestsketch/pom.xml
@@ -0,0 +1,94 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+ ~ 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.
+ -->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0";
+ xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
+ xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd";>
+ <parent>
+ <artifactId>druid</artifactId>
+ <groupId>org.apache.druid</groupId>
+ <version>0.15.0-incubating-SNAPSHOT</version>
+ <relativePath>../../pom.xml</relativePath>
+ </parent>
+ <modelVersion>4.0.0</modelVersion>
+
+ <groupId>io.druid.extensions.contrib</groupId>
+ <artifactId>druid-tdigestsketch</artifactId>
+ <name>tdigestsketch</name>
+ <description>Druid extension for generating tdigest backed
sketches</description>
+
+ <dependencies>
+ <dependency>
+ <groupId>com.tdunning</groupId>
+ <artifactId>t-digest</artifactId>
+ <version>3.2</version>
+ </dependency>
+ <dependency>
+ <groupId>com.google.guava</groupId>
+ <artifactId>guava</artifactId>
+ <version>${guava.version}</version>
+ <scope>provided</scope>
+ </dependency>
+ <dependency>
+ <groupId>org.apache.druid</groupId>
+ <artifactId>druid-core</artifactId>
+ <version>${project.parent.version}</version>
+ <scope>provided</scope>
+ </dependency>
+ <dependency>
+ <groupId>org.apache.druid</groupId>
+ <artifactId>druid-processing</artifactId>
+ <version>${project.parent.version}</version>
+ <scope>provided</scope>
+ </dependency>
+ <dependency>
+ <groupId>junit</groupId>
+ <artifactId>junit</artifactId>
+ <scope>test</scope>
+ </dependency>
+ <dependency>
+ <groupId>org.easymock</groupId>
+ <artifactId>easymock</artifactId>
+ <scope>test</scope>
+ </dependency>
+ <dependency>
+ <groupId>org.apache.druid</groupId>
+ <artifactId>druid-core</artifactId>
+ <version>${project.parent.version}</version>
+ <type>test-jar</type>
+ <scope>test</scope>
+ </dependency>
+ <dependency>
+ <groupId>org.apache.druid</groupId>
+ <artifactId>druid-processing</artifactId>
+ <version>${project.parent.version}</version>
+ <type>test-jar</type>
+ <scope>test</scope>
+ </dependency>
+ <dependency>
+ <groupId>org.apache.druid</groupId>
+ <artifactId>druid-server</artifactId>
+ <version>${project.parent.version}</version>
+ <scope>test</scope>
+ </dependency>
+
+ </dependencies>
+
+</project>
\ No newline at end of file
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchAggregator.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchAggregator.java
new file mode 100644
index 0000000..ae99778
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchAggregator.java
@@ -0,0 +1,93 @@
+/*
+ * 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.tdigestsketch;
+
+import com.tdunning.math.stats.MergingDigest;
+import org.apache.druid.query.aggregation.Aggregator;
+import org.apache.druid.segment.ColumnValueSelector;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.GuardedBy;
+
+/**
+ * Aggregator to build T-Digest sketches on numeric values.
+ * It generally makes sense to use this aggregator during the ingestion time.
+ * Then during query time one can use {@link TDigestMergeSketchAggregator} to
merge
+ * these pre-aggregated sketches.
+ * <p>
+ * One can use this aggregator to build these sketches during query time too,
just
+ * that it will be slower and more resource intensive.
+ */
+public class TDigestBuildSketchAggregator implements Aggregator
+{
+
+ private final ColumnValueSelector selector;
+
+ @GuardedBy("this")
+ private MergingDigest histogram;
+
+
+ public TDigestBuildSketchAggregator(ColumnValueSelector selector, @Nullable
Integer compression)
+ {
+ this.selector = selector;
+ if (compression != null) {
+ this.histogram = new MergingDigest(compression);
+ } else {
+ this.histogram = new
MergingDigest(TDigestBuildSketchAggregatorFactory.DEFAULT_COMPRESSION);
+ }
+ }
+
+ @Override
+ public void aggregate()
+ {
+ if (selector.getObject() instanceof Number) {
+ synchronized (this) {
+ histogram.add(((Number) selector.getObject()).doubleValue());
+ }
+ } else {
+ TDigestSketchUtils.throwExceptionForWrongType(selector);
+ }
+ }
+
+ @Nullable
+ @Override
+ public synchronized Object get()
+ {
+ return histogram;
+ }
+
+ @Override
+ public float getFloat()
+ {
+ throw new UnsupportedOperationException("Casting to float type is not
supported");
+ }
+
+ @Override
+ public long getLong()
+ {
+ throw new UnsupportedOperationException("Casting to long type is not
supported");
+ }
+
+ @Override
+ public synchronized void close()
+ {
+ histogram = null;
+ }
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchAggregatorFactory.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchAggregatorFactory.java
new file mode 100644
index 0000000..b12f3b3
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchAggregatorFactory.java
@@ -0,0 +1,268 @@
+/*
+ * 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.tdigestsketch;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.tdunning.math.stats.MergingDigest;
+import com.tdunning.math.stats.TDigest;
+import org.apache.druid.query.aggregation.Aggregator;
+import org.apache.druid.query.aggregation.AggregatorFactory;
+import
org.apache.druid.query.aggregation.AggregatorFactoryNotMergeableException;
+import org.apache.druid.query.aggregation.AggregatorUtil;
+import org.apache.druid.query.aggregation.BufferAggregator;
+import org.apache.druid.query.cache.CacheKeyBuilder;
+import org.apache.druid.segment.ColumnSelectorFactory;
+import org.apache.druid.segment.ColumnValueSelector;
+import org.apache.druid.segment.column.ColumnCapabilities;
+import org.apache.druid.segment.column.ValueType;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Aggregation operations over the tdigest-based quantile sketch
+ * available on <a href="https://github.com/tdunning/t-digest";>github</a> and
described
+ * in the paper
+ * <a
href="https://github.com/tdunning/t-digest/blob/master/docs/t-digest-paper/histo.pdf";>
+ * Computing extremely accurate quantiles using t-digests</a>.
+ * <p>
+ * <p>
+ * At the time of writing this implementation, there are two flavors of {@link
TDigest}
+ * available - {@link MergingDigest} and {@link
com.tdunning.math.stats.AVLTreeDigest}.
+ * This implementation uses {@link MergingDigest} since it is more suited for
the cases
+ * when we have to merge intermediate aggregations which Druid needs to do as
+ * part of query processing.
+ */
+public class TDigestBuildSketchAggregatorFactory extends AggregatorFactory
+{
+
+ // Default compression
+ public static final int DEFAULT_COMPRESSION = 100;
+
+ @Nonnull
+ private final String name;
+ @Nonnull
+ private final String fieldName;
+
+ private final int compression;
+
+ @Nonnull
+ private final byte cacheTypeId;
+
+ public static final String TYPE_NAME = "buildTDigestSketch";
+
+ @JsonCreator
+ public TDigestBuildSketchAggregatorFactory(
+ @JsonProperty("name") final String name,
+ @JsonProperty("fieldName") final String fieldName,
+ @Nullable @JsonProperty("compression") final Integer compression
+ )
+ {
+ this(name, fieldName, compression,
AggregatorUtil.TDIGEST_BUILD_SKETCH_CACHE_TYPE_ID);
+ }
+
+ TDigestBuildSketchAggregatorFactory(
+ final String name,
+ final String fieldName,
+ @Nullable final Integer compression,
+ final byte cacheTypeId
+ )
+ {
+ this.name = Objects.requireNonNull(name, "Must have a valid, non-null
aggregator name");
+ this.fieldName = Objects.requireNonNull(fieldName, "Parameter fieldName
must be specified");
+ this.compression = compression == null ? DEFAULT_COMPRESSION : compression;
+ this.cacheTypeId = cacheTypeId;
+ }
+
+
+ @Override
+ public byte[] getCacheKey()
+ {
+ return new CacheKeyBuilder(
+ cacheTypeId
+ ).appendString(fieldName).appendInt(compression).build();
+ }
+
+
+ @Override
+ public Aggregator factorize(ColumnSelectorFactory metricFactory)
+ {
+ ColumnCapabilities cap = metricFactory.getColumnCapabilities(fieldName);
+ if (cap == null || ValueType.isNumeric(cap.getType())) {
+ final ColumnValueSelector<Double> selector =
metricFactory.makeColumnValueSelector(fieldName);
+ return new TDigestBuildSketchAggregator(selector, compression);
+ } else {
+ final ColumnValueSelector<MergingDigest> selector =
metricFactory.makeColumnValueSelector(fieldName);
+ return new TDigestMergeSketchAggregator(selector, compression);
+ }
+ }
+
+ @Override
+ public BufferAggregator factorizeBuffered(ColumnSelectorFactory
metricFactory)
+ {
+ ColumnCapabilities cap = metricFactory.getColumnCapabilities(fieldName);
+ if (cap == null || ValueType.isNumeric(cap.getType())) {
+ final ColumnValueSelector<Double> selector =
metricFactory.makeColumnValueSelector(fieldName);
+ return new TDigestBuildSketchBufferAggregator(selector, compression);
+ } else {
+ final ColumnValueSelector<MergingDigest> selector =
metricFactory.makeColumnValueSelector(fieldName);
+ return new TDigestMergeSketchBufferAggregator(selector, compression);
+ }
+ }
+
+ public static final Comparator<TDigest> COMPARATOR = Comparator.nullsFirst(
+ Comparator.comparingLong(a -> a.size())
+ );
+
+ @Override
+ public Comparator getComparator()
+ {
+ return COMPARATOR;
+ }
+
+ @Override
+ public Object combine(@Nullable Object lhs, @Nullable Object rhs)
+ {
+ if (lhs == null) {
+ return rhs;
+ }
+ if (rhs == null) {
+ return lhs;
+ }
+ TDigest union = (TDigest) lhs;
+ union.add((TDigest) rhs);
+ return union;
+ }
+
+ @Override
+ public AggregatorFactory getCombiningFactory()
+ {
+ return new TDigestMergeSketchAggregatorFactory(name, name, compression);
+ }
+
+ @Override
+ public AggregatorFactory getMergingFactory(AggregatorFactory other) throws
AggregatorFactoryNotMergeableException
+ {
+ if (other.getName().equals(this.getName()) && this.getClass() ==
other.getClass()) {
+ return getCombiningFactory();
+ } else {
+ throw new AggregatorFactoryNotMergeableException(this, other);
+ }
+ }
+
+ @Override
+ public List<AggregatorFactory> getRequiredColumns()
+ {
+ return Collections.singletonList(
+ new TDigestBuildSketchAggregatorFactory(
+ fieldName,
+ fieldName,
+ compression
+ )
+ );
+ }
+
+ @Override
+ public Object deserialize(Object serializedSketch)
+ {
+ return TDigestSketchUtils.deserialize(serializedSketch);
+ }
+
+ @Override
+ public Object finalizeComputation(Object object)
+ {
+ return object;
+ }
+
+ @Override
+ @JsonProperty
+ public String getName()
+ {
+ return name;
+ }
+
+ @JsonProperty
+ public String getFieldName()
+ {
+ return fieldName;
+ }
+
+ @JsonProperty
+ public int getCompression()
+ {
+ return compression;
+ }
+
+ @Override
+ public List<String> requiredFields()
+ {
+ return Collections.singletonList(fieldName);
+ }
+
+ @Override
+ public String getTypeName()
+ {
+ return TYPE_NAME;
+ }
+
+ @Override
+ public int getMaxIntermediateSize()
+ {
+ return TDigestSketchUtils.getMaxIntermdiateTDigestSize(compression);
+ }
+
+ @Override
+ public boolean equals(final Object o)
+ {
+ if (this == o) {
+ return true;
+ }
+ if (o == null || !getClass().equals(o.getClass())) {
+ return false;
+ }
+ final TDigestBuildSketchAggregatorFactory that =
(TDigestBuildSketchAggregatorFactory) o;
+
+ return Objects.equals(name, that.name) &&
+ Objects.equals(fieldName, that.fieldName) &&
+ compression == that.compression;
+ }
+
+ @Override
+ public int hashCode()
+ {
+ return Objects.hash(name, fieldName, compression);
+ }
+
+ @Override
+ public String toString()
+ {
+ return getClass().getSimpleName() + "{"
+ + "name=" + name
+ + ", fieldName=" + fieldName
+ + ", compression=" + compression
+ + "}";
+ }
+
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchBufferAggregator.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchBufferAggregator.java
new file mode 100644
index 0000000..a9f1dd1e
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchBufferAggregator.java
@@ -0,0 +1,121 @@
+/*
+ * 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.tdigestsketch;
+
+import com.google.common.base.Preconditions;
+import com.tdunning.math.stats.MergingDigest;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import org.apache.druid.query.aggregation.BufferAggregator;
+import org.apache.druid.segment.ColumnValueSelector;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.nio.ByteBuffer;
+import java.util.IdentityHashMap;
+
+/**
+ * Aggregator that builds T-Digest backed sketch using numeric values read
from {@link ByteBuffer}
+ */
+public class TDigestBuildSketchBufferAggregator implements BufferAggregator
+{
+
+ @Nonnull
+ private final ColumnValueSelector selector;
+ private final int compression;
+ private final IdentityHashMap<ByteBuffer, Int2ObjectMap<MergingDigest>>
sketchCache = new IdentityHashMap();
+
+ public TDigestBuildSketchBufferAggregator(
+ final ColumnValueSelector valueSelector,
+ @Nullable final Integer compression
+ )
+ {
+ Preconditions.checkNotNull(valueSelector);
+ this.selector = valueSelector;
+ if (compression != null) {
+ this.compression = compression;
+ } else {
+ this.compression =
TDigestBuildSketchAggregatorFactory.DEFAULT_COMPRESSION;
+ }
+ }
+
+ @Override
+ public void init(ByteBuffer buffer, int position)
+ {
+ MergingDigest emptyDigest = new MergingDigest(compression);
+ addToCache(buffer, position, emptyDigest);
+ }
+
+ @Override
+ public void aggregate(ByteBuffer buffer, int position)
+ {
+ MergingDigest sketch = sketchCache.get(buffer).get(position);
+ Object x = selector.getObject();
+ if (x instanceof Number) {
+ sketch.add(((Number) x).doubleValue());
+ } else {
+ TDigestSketchUtils.throwExceptionForWrongType(selector);
+ }
+ }
+
+ @Override
+ public Object get(final ByteBuffer buffer, final int position)
+ {
+ // sketchCache is an IdentityHashMap where the reference of buffer is used
for equality checks.
+ // So the returned object isn't impacted by the changes in the buffer
object made by concurrent threads.
+ return sketchCache.get(buffer).get(position);
+ }
+
+ @Override
+ public float getFloat(final ByteBuffer buffer, final int position)
+ {
+ throw new UnsupportedOperationException("Not implemented");
+ }
+
+ @Override
+ public long getLong(final ByteBuffer buffer, final int position)
+ {
+ throw new UnsupportedOperationException("Not implemented");
+ }
+
+ @Override
+ public void close()
+ {
+ sketchCache.clear();
+ }
+
+ @Override
+ public void relocate(int oldPosition, int newPosition, ByteBuffer oldBuffer,
ByteBuffer newBuffer)
+ {
+ MergingDigest sketch = sketchCache.get(oldBuffer).get(oldPosition);
+ addToCache(newBuffer, newPosition, sketch);
+ final Int2ObjectMap<MergingDigest> map = sketchCache.get(oldBuffer);
+ map.remove(oldPosition);
+ if (map.isEmpty()) {
+ sketchCache.remove(oldBuffer);
+ }
+ }
+
+ private void addToCache(final ByteBuffer buffer, final int position, final
MergingDigest sketch)
+ {
+ Int2ObjectMap<MergingDigest> map = sketchCache.computeIfAbsent(buffer, b
-> new Int2ObjectOpenHashMap<>());
+ map.put(position, sketch);
+ }
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestMergeSketchAggregator.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestMergeSketchAggregator.java
new file mode 100644
index 0000000..b8dfd54
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestMergeSketchAggregator.java
@@ -0,0 +1,83 @@
+/*
+ * 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.tdigestsketch;
+
+import com.tdunning.math.stats.MergingDigest;
+import org.apache.druid.query.aggregation.Aggregator;
+import org.apache.druid.segment.ColumnValueSelector;
+
+import javax.annotation.concurrent.GuardedBy;
+
+/**
+ * Aggregator that merges T-Digest based sketches generated from {@link
TDigestBuildSketchAggregator}
+ */
+public class TDigestMergeSketchAggregator implements Aggregator
+{
+ private final ColumnValueSelector<MergingDigest> selector;
+
+ @GuardedBy("this")
+ private MergingDigest tdigestSketch;
+
+ public TDigestMergeSketchAggregator(
+ ColumnValueSelector<MergingDigest> selector,
+ final Integer compression
+ )
+ {
+ this.selector = selector;
+ this.tdigestSketch = new MergingDigest(compression);
+ }
+
+ @Override
+ public void aggregate()
+ {
+ final MergingDigest sketch = selector.getObject();
+ if (sketch == null) {
+ return;
+ }
+ synchronized (this) {
+ this.tdigestSketch.add(sketch);
+ }
+ }
+
+ @Override
+ public synchronized Object get()
+ {
+ return tdigestSketch;
+ }
+
+ @Override
+ public float getFloat()
+ {
+ throw new UnsupportedOperationException("Not implemented");
+ }
+
+ @Override
+ public long getLong()
+ {
+ throw new UnsupportedOperationException("Not implemented");
+ }
+
+ @Override
+ public synchronized void close()
+ {
+ tdigestSketch = null;
+ }
+
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestMergeSketchAggregatorFactory.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestMergeSketchAggregatorFactory.java
new file mode 100644
index 0000000..9a0e9a9
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestMergeSketchAggregatorFactory.java
@@ -0,0 +1,64 @@
+/*
+ * 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.tdigestsketch;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.tdunning.math.stats.MergingDigest;
+import org.apache.druid.query.aggregation.Aggregator;
+import org.apache.druid.query.aggregation.AggregatorUtil;
+import org.apache.druid.query.aggregation.BufferAggregator;
+import org.apache.druid.segment.ColumnSelectorFactory;
+import org.apache.druid.segment.ColumnValueSelector;
+
+/**
+ * Factory to create {@link TDigestMergeSketchAggregator}
+ */
+public class TDigestMergeSketchAggregatorFactory extends
TDigestBuildSketchAggregatorFactory
+{
+ public static final String TYPE_NAME = "mergeTDigestSketch";
+
+ @JsonCreator
+ public TDigestMergeSketchAggregatorFactory(
+ @JsonProperty("name") final String name,
+ @JsonProperty("fieldName") final String fieldName,
+ @JsonProperty("compression") final Integer compression
+ )
+ {
+ super(name, fieldName, compression,
AggregatorUtil.TDIGEST_MERGE_SKETCH_CACHE_TYPE_ID);
+ }
+
+ @Override
+ public Aggregator factorize(final ColumnSelectorFactory metricFactory)
+ {
+ final ColumnValueSelector<MergingDigest> selector =
metricFactory.makeColumnValueSelector(
+ getFieldName());
+ return new TDigestMergeSketchAggregator(selector, getCompression());
+ }
+
+ @Override
+ public BufferAggregator factorizeBuffered(final ColumnSelectorFactory
metricFactory)
+ {
+ final ColumnValueSelector<MergingDigest> selector =
metricFactory.makeColumnValueSelector(
+ getFieldName()
+ );
+ return new TDigestMergeSketchBufferAggregator(selector, getCompression());
+ }
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestMergeSketchBufferAggregator.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestMergeSketchBufferAggregator.java
new file mode 100644
index 0000000..da4423e
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestMergeSketchBufferAggregator.java
@@ -0,0 +1,110 @@
+/*
+ * 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.tdigestsketch;
+
+import com.tdunning.math.stats.MergingDigest;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import org.apache.druid.query.aggregation.BufferAggregator;
+import org.apache.druid.segment.ColumnValueSelector;
+
+import java.nio.ByteBuffer;
+import java.util.IdentityHashMap;
+
+/**
+ * Aggregator that is capable of combining T-Digest sketch serialized as
{@link ByteBuffer}
+ */
+public class TDigestMergeSketchBufferAggregator implements BufferAggregator
+{
+ private final ColumnValueSelector<MergingDigest> selector;
+ private final int compression;
+ private final IdentityHashMap<ByteBuffer, Int2ObjectMap<MergingDigest>>
sketchCache = new IdentityHashMap();
+
+ public TDigestMergeSketchBufferAggregator(
+ ColumnValueSelector<MergingDigest> selector,
+ int compression
+ )
+ {
+ this.selector = selector;
+ this.compression = compression;
+ }
+
+ @Override
+ public void init(ByteBuffer buffer, int position)
+ {
+ MergingDigest emptyDigest = new MergingDigest(compression);
+ addToCache(buffer, position, emptyDigest);
+ }
+
+ @Override
+ public void aggregate(ByteBuffer buffer, int position)
+ {
+ final MergingDigest sketch = selector.getObject();
+ if (sketch == null) {
+ return;
+ }
+ final MergingDigest union = sketchCache.get(buffer).get(position);
+ union.add(sketch);
+ }
+
+ @Override
+ public Object get(ByteBuffer buffer, int position)
+ {
+ // sketchCache is an IdentityHashMap where the reference of buffer is used
for equality checks.
+ // So the returned object isn't impacted by the changes in the buffer
object made by concurrent threads.
+ return sketchCache.get(buffer).get(position);
+ }
+
+ @Override
+ public float getFloat(final ByteBuffer buffer, final int position)
+ {
+ throw new UnsupportedOperationException("Not implemented");
+ }
+
+ @Override
+ public long getLong(final ByteBuffer buffer, final int position)
+ {
+ throw new UnsupportedOperationException("Not implemented");
+ }
+
+ @Override
+ public void close()
+ {
+ sketchCache.clear();
+ }
+
+ @Override
+ public void relocate(int oldPosition, int newPosition, ByteBuffer oldBuffer,
ByteBuffer newBuffer)
+ {
+ MergingDigest sketch = sketchCache.get(oldBuffer).get(oldPosition);
+ addToCache(newBuffer, newPosition, sketch);
+ final Int2ObjectMap<MergingDigest> map = sketchCache.get(oldBuffer);
+ map.remove(oldPosition);
+ if (map.isEmpty()) {
+ sketchCache.remove(oldBuffer);
+ }
+ }
+
+ private void addToCache(final ByteBuffer buffer, final int position, final
MergingDigest union)
+ {
+ Int2ObjectMap<MergingDigest> map = sketchCache.computeIfAbsent(buffer, b
-> new Int2ObjectOpenHashMap<>());
+ map.put(position, union);
+ }
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchComplexMetricSerde.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchComplexMetricSerde.java
new file mode 100644
index 0000000..52522b8
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchComplexMetricSerde.java
@@ -0,0 +1,111 @@
+/*
+ * 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.tdigestsketch;
+
+import com.tdunning.math.stats.MergingDigest;
+import org.apache.druid.data.input.InputRow;
+import org.apache.druid.java.util.common.IAE;
+import org.apache.druid.segment.GenericColumnSerializer;
+import org.apache.druid.segment.column.ColumnBuilder;
+import org.apache.druid.segment.data.GenericIndexed;
+import org.apache.druid.segment.data.ObjectStrategy;
+import org.apache.druid.segment.serde.ComplexColumnPartSupplier;
+import org.apache.druid.segment.serde.ComplexMetricExtractor;
+import org.apache.druid.segment.serde.ComplexMetricSerde;
+import
org.apache.druid.segment.serde.LargeColumnSupportedComplexColumnSerializer;
+import org.apache.druid.segment.writeout.SegmentWriteOutMedium;
+
+import java.nio.ByteBuffer;
+
+public class TDigestSketchComplexMetricSerde extends ComplexMetricSerde
+{
+ private static final TDigestSketchObjectStrategy STRATEGY = new
TDigestSketchObjectStrategy();
+
+ @Override
+ public String getTypeName()
+ {
+ return TDigestBuildSketchAggregatorFactory.TYPE_NAME;
+ }
+
+ @Override
+ public ComplexMetricExtractor getExtractor()
+ {
+ return new ComplexMetricExtractor()
+ {
+ @Override
+ public Class<?> extractedClass()
+ {
+ return MergingDigest.class;
+ }
+
+ @Override
+ public Object extractValue(final InputRow inputRow, final String
metricName)
+ {
+ final Object object = inputRow.getRaw(metricName);
+ if (object == null || object instanceof Number || object instanceof
MergingDigest) {
+ return object;
+ }
+ if (object instanceof String) {
+ String objectString = (String) object;
+ if (Character.isDigit((objectString).charAt(0))) {
+ // Base64 representation of MergingDigest starts with A. So if
it's a
+ // string that starts with a digit, we assume it is a number.
+ try {
+ Double doubleValue = Double.parseDouble(objectString);
+ return doubleValue;
+ }
+ catch (NumberFormatException e) {
+ throw new IAE("Expected a string with a number, received value "
+ objectString);
+ }
+ }
+ }
+ return TDigestSketchUtils.deserialize(object);
+ }
+ };
+ }
+
+ @Override
+ public void deserializeColumn(ByteBuffer buffer, ColumnBuilder builder)
+ {
+ final GenericIndexed<MergingDigest> column = GenericIndexed.read(
+ buffer,
+ STRATEGY,
+ builder.getFileMapper()
+ );
+ builder.setComplexColumnSupplier(new
ComplexColumnPartSupplier(getTypeName(), column));
+ }
+
+ @Override
+ public ObjectStrategy<MergingDigest> getObjectStrategy()
+ {
+ return STRATEGY;
+ }
+
+ @Override
+ public GenericColumnSerializer getSerializer(SegmentWriteOutMedium
segmentWriteOutMedium, String column)
+ {
+ return LargeColumnSupportedComplexColumnSerializer.create(
+ segmentWriteOutMedium,
+ column,
+ this.getObjectStrategy()
+ );
+ }
+
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchJsonSerializer.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchJsonSerializer.java
new file mode 100644
index 0000000..b8a3ebd
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchJsonSerializer.java
@@ -0,0 +1,41 @@
+/*
+ * 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.tdigestsketch;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.tdunning.math.stats.MergingDigest;
+
+import java.io.IOException;
+
+public class TDigestSketchJsonSerializer extends JsonSerializer<MergingDigest>
+{
+ @Override
+ public void serialize(
+ MergingDigest tDigest,
+ JsonGenerator jsonGenerator,
+ SerializerProvider serializerProvider
+ ) throws IOException
+ {
+ jsonGenerator.writeBinary(TDigestSketchUtils.toBytes(tDigest));
+ }
+
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchModule.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchModule.java
new file mode 100644
index 0000000..47ab317
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchModule.java
@@ -0,0 +1,76 @@
+/*
+ * 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.tdigestsketch;
+
+import com.fasterxml.jackson.databind.Module;
+import com.fasterxml.jackson.databind.jsontype.NamedType;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.ImmutableList;
+import com.google.inject.Binder;
+import com.tdunning.math.stats.MergingDigest;
+import org.apache.druid.initialization.DruidModule;
+import org.apache.druid.segment.serde.ComplexMetrics;
+
+import java.util.List;
+
+/**
+ * Module defining aggregators for the T-Digest based sketches
+ */
+public class TDigestSketchModule implements DruidModule
+{
+ @Override
+ public List<? extends Module> getJacksonModules()
+ {
+ return ImmutableList.of(
+ new SimpleModule(
+ getClass().getSimpleName()
+ ).registerSubtypes(
+ new NamedType(
+ TDigestBuildSketchAggregatorFactory.class,
+ TDigestBuildSketchAggregatorFactory.TYPE_NAME
+ ),
+ new NamedType(
+ TDigestMergeSketchAggregatorFactory.class,
+ TDigestMergeSketchAggregatorFactory.TYPE_NAME
+ ),
+ new NamedType(
+ TDigestSketchToQuantilesPostAggregator.class,
+ TDigestSketchToQuantilesPostAggregator.TYPE_NAME
+ )
+ ).addSerializer(MergingDigest.class, new TDigestSketchJsonSerializer())
+ );
+ }
+
+ @Override
+ public void configure(Binder binder)
+ {
+ registerSerde();
+ }
+
+ @VisibleForTesting
+ static void registerSerde()
+ {
+ if
(ComplexMetrics.getSerdeForType(TDigestBuildSketchAggregatorFactory.TYPE_NAME)
== null) {
+
ComplexMetrics.registerSerde(TDigestBuildSketchAggregatorFactory.TYPE_NAME, new
TDigestSketchComplexMetricSerde());
+ }
+ }
+
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchObjectStrategy.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchObjectStrategy.java
new file mode 100644
index 0000000..765e707
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchObjectStrategy.java
@@ -0,0 +1,63 @@
+/*
+ * 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.tdigestsketch;
+
+import com.tdunning.math.stats.MergingDigest;
+import org.apache.druid.segment.data.ObjectStrategy;
+
+import javax.annotation.Nullable;
+import java.nio.ByteBuffer;
+
+public class TDigestSketchObjectStrategy implements
ObjectStrategy<MergingDigest>
+{
+ private static final byte[] EMPTY_BYTES = new byte[0];
+
+ @Override
+ public Class<MergingDigest> getClazz()
+ {
+ return MergingDigest.class;
+ }
+
+ @Override
+ public MergingDigest fromByteBuffer(ByteBuffer buffer, int numBytes)
+ {
+ if (numBytes == 0) {
+ return null;
+ }
+ ByteBuffer readOnlyBuffer = buffer.asReadOnlyBuffer();
+ readOnlyBuffer.limit(buffer.position() + numBytes);
+ return MergingDigest.fromBytes(readOnlyBuffer);
+ }
+
+ @Override
+ public byte[] toBytes(@Nullable MergingDigest val)
+ {
+ if (val == null) {
+ return EMPTY_BYTES;
+ }
+ return TDigestSketchUtils.toBytes(val);
+ }
+
+ @Override
+ public int compare(MergingDigest o1, MergingDigest o2)
+ {
+ return TDigestBuildSketchAggregatorFactory.COMPARATOR.compare(o1, o2);
+ }
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchToQuantilesPostAggregator.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchToQuantilesPostAggregator.java
new file mode 100644
index 0000000..485a397
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchToQuantilesPostAggregator.java
@@ -0,0 +1,159 @@
+/*
+ * 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.tdigestsketch;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.google.common.base.Preconditions;
+import com.tdunning.math.stats.MergingDigest;
+import org.apache.druid.java.util.common.IAE;
+import org.apache.druid.query.aggregation.AggregatorFactory;
+import org.apache.druid.query.aggregation.AggregatorUtil;
+import org.apache.druid.query.aggregation.PostAggregator;
+import org.apache.druid.query.cache.CacheKeyBuilder;
+
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Post aggregation operator that can take in aggregated T-Digest sketches and
+ * generate quantiles from it.
+ */
+public class TDigestSketchToQuantilesPostAggregator implements PostAggregator
+{
+
+ private final String name;
+ private final PostAggregator field;
+ private final double[] fractions;
+
+ public static final String TYPE_NAME = "quantilesFromTDigestSketch";
+
+ @JsonCreator
+ public TDigestSketchToQuantilesPostAggregator(
+ @JsonProperty("name") final String name,
+ @JsonProperty("field") final PostAggregator field,
+ @JsonProperty("fractions") final double[] fractions
+ )
+ {
+ this.name = Preconditions.checkNotNull(name, "name is null");
+ this.field = Preconditions.checkNotNull(field, "field is null");
+ this.fractions = Preconditions.checkNotNull(fractions, "array of fractions
is null");
+ Preconditions.checkArgument(this.fractions.length > 1, "Array of fractions
cannot be empty");
+ }
+
+ @Override
+ @JsonProperty
+ public String getName()
+ {
+ return name;
+ }
+
+ @JsonProperty
+ public PostAggregator getField()
+ {
+ return field;
+ }
+
+ @JsonProperty
+ public double[] getFractions()
+ {
+ return fractions;
+ }
+
+ @Override
+ public Object compute(final Map<String, Object> combinedAggregators)
+ {
+ final MergingDigest sketch = (MergingDigest)
field.compute(combinedAggregators);
+ double[] quantiles = new double[fractions.length];
+ int i = 0;
+
+ for (double f : fractions) {
+ quantiles[i++] = sketch.quantile(f);
+ }
+ return quantiles;
+ }
+
+ @Override
+ public Comparator<double[]> getComparator()
+ {
+ throw new IAE("Comparing arrays of quantiles is not supported");
+ }
+
+ @Override
+ public Set<String> getDependentFields()
+ {
+ return field.getDependentFields();
+ }
+
+ @Override
+ public String toString()
+ {
+ return getClass().getSimpleName() + "{" +
+ "name='" + name + '\'' +
+ ", field=" + field +
+ ", fractions=" + Arrays.toString(fractions) +
+ "}";
+ }
+
+ @Override
+ public boolean equals(final Object o)
+ {
+ if (this == o) {
+ return true;
+ }
+ if (o == null || getClass() != o.getClass()) {
+ return false;
+ }
+ final TDigestSketchToQuantilesPostAggregator that =
(TDigestSketchToQuantilesPostAggregator) o;
+ if (!name.equals(that.name)) {
+ return false;
+ }
+ if (!Arrays.equals(fractions, that.fractions)) {
+ return false;
+ }
+ return field.equals(that.field);
+ }
+
+ @Override
+ public int hashCode()
+ {
+ return (name.hashCode() * 31 + field.hashCode()) * 31 +
Arrays.hashCode(fractions);
+ }
+
+ @Override
+ public byte[] getCacheKey()
+ {
+ final CacheKeyBuilder builder = new CacheKeyBuilder(
+
AggregatorUtil.TDIGEST_SKETCH_TO_QUANTILES_CACHE_TYPE_ID).appendCacheable(field);
+ for (final double value : fractions) {
+ builder.appendDouble(value);
+ }
+ return builder.build();
+ }
+
+ @Override
+ public PostAggregator decorate(final Map<String, AggregatorFactory> map)
+ {
+ return this;
+ }
+
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchUtils.java
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchUtils.java
new file mode 100644
index 0000000..0a5d9a1
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchUtils.java
@@ -0,0 +1,90 @@
+/*
+ * 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.tdigestsketch;
+
+import com.tdunning.math.stats.MergingDigest;
+import org.apache.druid.java.util.common.IAE;
+import org.apache.druid.java.util.common.StringUtils;
+import org.apache.druid.segment.ColumnValueSelector;
+
+import java.nio.ByteBuffer;
+
+public class TDigestSketchUtils
+{
+ // Class is not meant to be instantiated
+ private TDigestSketchUtils()
+ {
+ }
+
+ public static MergingDigest deserialize(Object serializedSketch)
+ {
+ if (serializedSketch instanceof String) {
+ String str = (String) serializedSketch;
+ return
MergingDigest.fromBytes(ByteBuffer.wrap(StringUtils.decodeBase64(StringUtils.toUtf8(str))));
+ } else if (serializedSketch instanceof byte[]) {
+ return MergingDigest.fromBytes(ByteBuffer.wrap((byte[])
serializedSketch));
+ } else if (serializedSketch instanceof MergingDigest) {
+ return (MergingDigest) serializedSketch;
+ }
+ throw new IAE(
+ "Object cannot be deserialized to a TDigest Sketch: "
+ + serializedSketch.getClass()
+ );
+ }
+
+ static byte[] toBytes(MergingDigest tDigest)
+ {
+ byte[] arr = new byte[tDigest.byteSize()];
+ ByteBuffer result = ByteBuffer.wrap(arr);
+ tDigest.asBytes(result);
+ return result.array();
+ }
+
+ /**
+ * This method computes an estimate of the max intermediate size of a {@link
MergingDigest}.
+ * Since there is no utility available in the T-Digest library to compute
this size,
+ * the below code is inspired by looking at
+ * {@link MergingDigest#MergingDigest(double, int, int)}
+ * This method is current as of 3.2 version and many need to change in
future.
+ */
+ static int getMaxIntermdiateTDigestSize(int compression)
+ {
+ int intermediateSize = 0;
+ int centroidArraySize = (int) (2 * Math.ceil(compression)) + 10;
+ intermediateSize += 2 * centroidArraySize * Double.BYTES;
+ int tempBufferSize = (int) (5 * Math.ceil(compression));
+ intermediateSize += 2 * tempBufferSize * Double.BYTES;
+ intermediateSize += tempBufferSize * Integer.BYTES;
+ // Adding an extra buffer of 1K for overhead
+ return intermediateSize + 1000;
+ }
+
+ static void throwExceptionForWrongType(ColumnValueSelector selector)
+ {
+ final String msg = selector.getObject() == null
+ ? StringUtils.format("Expected a number, but received
null")
+ : StringUtils.format(
+ "Expected a number, but received [%s] of type [%s]",
+ selector.getObject(),
+ selector.getObject().getClass()
+ );
+ throw new IAE(msg);
+ }
+}
diff --git
a/extensions-contrib/tdigestsketch/src/main/resources/META-INF/services/org.apache.druid.initialization.DruidModule
b/extensions-contrib/tdigestsketch/src/main/resources/META-INF/services/org.apache.druid.initialization.DruidModule
new file mode 100644
index 0000000..89a2389
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/main/resources/META-INF/services/org.apache.druid.initialization.DruidModule
@@ -0,0 +1,16 @@
+# 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.
+
+org.apache.druid.query.aggregation.tdigestsketch.TDigestSketchModule
diff --git
a/extensions-contrib/tdigestsketch/src/test/java/org/apache/druid/query/aggregation/tdigestsketch/GenerateTestData.java
b/extensions-contrib/tdigestsketch/src/test/java/org/apache/druid/query/aggregation/tdigestsketch/GenerateTestData.java
new file mode 100644
index 0000000..b6a2392
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/test/java/org/apache/druid/query/aggregation/tdigestsketch/GenerateTestData.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.tdigestsketch;
+
+import com.tdunning.math.stats.MergingDigest;
+import org.apache.druid.java.util.common.StringUtils;
+
+import java.io.BufferedWriter;
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
+
+/**
+ * This class is largely a copy of GenerateTestData class for Datasketches
project.
+ * It is used for generating test data for {@link TDigestSketchAggregatorTest}.
+ */
+public class GenerateTestData
+{
+
+ public static void main(String[] args) throws Exception
+ {
+ Path buildPath =
FileSystems.getDefault().getPath("doubles_build_data.tsv");
+ Path sketchPath =
FileSystems.getDefault().getPath("doubles_sketch_data.tsv");
+ BufferedWriter buildData = Files.newBufferedWriter(buildPath,
StandardCharsets.UTF_8);
+ BufferedWriter sketchData = Files.newBufferedWriter(sketchPath,
StandardCharsets.UTF_8);
+ Random rand = ThreadLocalRandom.current();
+ int sequenceNumber = 0;
+ for (int i = 0; i < 20; i++) {
+ int product = rand.nextInt(10);
+ MergingDigest sketch = new MergingDigest(100);
+ for (int j = 0; j < 20; j++) {
+ double value = rand.nextDouble();
+ buildData.write("2016010101");
+ buildData.write('\t');
+ buildData.write(Integer.toString(sequenceNumber)); // dimension with
unique numbers for ingesting raw data
+ buildData.write('\t');
+ buildData.write(Integer.toString(product)); // product dimension
+ buildData.write('\t');
+ buildData.write(Double.toString(value));
+ buildData.newLine();
+ sketch.add(value);
+ sequenceNumber++;
+ }
+ sketchData.write("2016010101");
+ sketchData.write('\t');
+ sketchData.write(Integer.toString(product)); // product dimension
+ sketchData.write('\t');
+ byte[] bytes = new byte[sketch.byteSize()];
+ ByteBuffer buffer = ByteBuffer.wrap(bytes);
+ sketch.asBytes(buffer);
+ sketchData.write(StringUtils.encodeBase64String(buffer.array()));
+ sketchData.newLine();
+ }
+ buildData.close();
+ sketchData.close();
+ }
+
+}
diff --git
a/extensions-contrib/tdigestsketch/src/test/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchAggregatorTest.java
b/extensions-contrib/tdigestsketch/src/test/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchAggregatorTest.java
new file mode 100644
index 0000000..88adde0
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/test/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestSketchAggregatorTest.java
@@ -0,0 +1,279 @@
+/*
+ * 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.tdigestsketch;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.druid.data.input.Row;
+import org.apache.druid.jackson.DefaultObjectMapper;
+import org.apache.druid.java.util.common.granularity.Granularities;
+import org.apache.druid.java.util.common.guava.Sequence;
+import org.apache.druid.query.aggregation.AggregationTestHelper;
+import org.apache.druid.query.aggregation.AggregatorFactory;
+import org.apache.druid.query.groupby.GroupByQueryConfig;
+import org.apache.druid.query.groupby.GroupByQueryRunnerTest;
+import org.junit.Assert;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+@RunWith(Parameterized.class)
+public class TDigestSketchAggregatorTest
+{
+
+ private final AggregationTestHelper helper;
+
+ @Rule
+ public final TemporaryFolder tempFolder = new TemporaryFolder();
+
+ public TDigestSketchAggregatorTest(final GroupByQueryConfig config)
+ {
+ TDigestSketchModule.registerSerde();
+ TDigestSketchModule module = new TDigestSketchModule();
+ helper = AggregationTestHelper.createGroupByQueryAggregationTestHelper(
+ module.getJacksonModules(), config, tempFolder);
+ }
+
+ @Parameterized.Parameters(name = "{0}")
+ public static Collection<?> constructorFeeder()
+ {
+ final List<Object[]> constructors = new ArrayList<>();
+ for (GroupByQueryConfig config : GroupByQueryRunnerTest.testConfigs()) {
+ constructors.add(new Object[]{config});
+ }
+ return constructors;
+ }
+
+ // this is to test Json properties and equals
+ @Test
+ public void serializeDeserializeFactoryWithFieldName() throws Exception
+ {
+ ObjectMapper objectMapper = new DefaultObjectMapper();
+ new
TDigestSketchModule().getJacksonModules().forEach(objectMapper::registerModule);
+ TDigestBuildSketchAggregatorFactory factory = new
TDigestBuildSketchAggregatorFactory("name", "filedName", 128);
+
+ AggregatorFactory other = objectMapper.readValue(
+ objectMapper.writeValueAsString(factory),
+ AggregatorFactory.class
+ );
+
+ Assert.assertEquals(factory, other);
+ }
+
+ // this is to test Json properties and equals for the combining factory
+ @Test
+ public void serializeDeserializeCombiningFactoryWithFieldName() throws
Exception
+ {
+ ObjectMapper objectMapper = new DefaultObjectMapper();
+ new
TDigestSketchModule().getJacksonModules().forEach(objectMapper::registerModule);
+ TDigestMergeSketchAggregatorFactory factory = new
TDigestMergeSketchAggregatorFactory("name", "fieldName", 128);
+
+ AggregatorFactory other = objectMapper.readValue(
+ objectMapper.writeValueAsString(factory),
+ AggregatorFactory.class
+ );
+
+ Assert.assertEquals(factory, other);
+ }
+
+ @Test
+ public void buildingSketchesAtIngestionTime() throws Exception
+ {
+ Sequence<Row> seq = helper.createIndexAndRunQueryOnSegment(
+ new
File(this.getClass().getClassLoader().getResource("doubles_build_data.tsv").getFile()),
+ String.join(
+ "\n",
+ "{",
+ " \"type\": \"string\",",
+ " \"parseSpec\": {",
+ " \"format\": \"tsv\",",
+ " \"timestampSpec\": {\"column\": \"timestamp\", \"format\":
\"yyyyMMddHH\"},",
+ " \"dimensionsSpec\": {",
+ " \"dimensions\": [\"product\"],",
+ " \"dimensionExclusions\": [ \"sequenceNumber\"],",
+ " \"spatialDimensions\": []",
+ " },",
+ " \"columns\": [\"timestamp\", \"sequenceNumber\", \"product\",
\"value\"]",
+ " }",
+ "}"
+ ),
+ "[{\"type\": \"buildTDigestSketch\", \"name\": \"sketch\",
\"fieldName\": \"value\", \"compression\": 200}]",
+ 0, // minTimestamp
+ Granularities.NONE,
+ 10, // maxRowCount
+ String.join(
+ "\n",
+ "{",
+ " \"queryType\": \"groupBy\",",
+ " \"dataSource\": \"test_datasource\",",
+ " \"granularity\": \"ALL\",",
+ " \"dimensions\": [],",
+ " \"aggregations\": [",
+ " {\"type\": \"mergeTDigestSketch\", \"name\":
\"merged_sketch\", \"fieldName\": \"sketch\", "
+ + "\"compression\": "
+ + "200}",
+ " ],",
+ " \"postAggregations\": [",
+ " {\"type\": \"quantilesFromTDigestSketch\", \"name\":
\"quantiles\", \"fractions\": [0, 0.5, 1], "
+ + "\"field\": {\"type\": \"fieldAccess\", \"fieldName\":
\"merged_sketch\"}}",
+ " ],",
+ " \"intervals\":
[\"2016-01-01T00:00:00.000Z/2016-01-31T00:00:00.000Z\"]",
+ "}"
+ )
+ );
+ List<Row> results = seq.toList();
+ Assert.assertEquals(1, results.size());
+ Row row = results.get(0);
+
+ // post agg
+ Object quantilesObject = row.getRaw("quantiles");
+ Assert.assertTrue(quantilesObject instanceof double[]);
+ double[] quantiles = (double[]) quantilesObject;
+ Assert.assertEquals(0, quantiles[0], 0.05); // min value
+ Assert.assertEquals(0.5, quantiles[1], 0.05); // median value
+ Assert.assertEquals(1, quantiles[2], 0.05); // max value
+ }
+
+ @Test
+ public void buildingSketchesAtQueryTime() throws Exception
+ {
+ Sequence<Row> seq = helper.createIndexAndRunQueryOnSegment(
+ new
File(this.getClass().getClassLoader().getResource("doubles_build_data.tsv").getFile()),
+ String.join(
+ "\n",
+ "{",
+ " \"type\": \"string\",",
+ " \"parseSpec\": {",
+ " \"format\": \"tsv\",",
+ " \"timestampSpec\": {\"column\": \"timestamp\", \"format\":
\"yyyyMMddHH\"},",
+ " \"dimensionsSpec\": {",
+ " \"dimensions\": [\"sequenceNumber\", \"product\"],",
+ " \"dimensionExclusions\": [],",
+ " \"spatialDimensions\": []",
+ " },",
+ " \"columns\": [\"timestamp\", \"sequenceNumber\", \"product\",
\"value\"]",
+ " }",
+ "}"
+ ),
+ "[{\"type\": \"doubleSum\", \"name\": \"value\", \"fieldName\":
\"value\"}]",
+ 0, // minTimestamp
+ Granularities.NONE,
+ 10, // maxRowCount
+ String.join(
+ "\n",
+ "{",
+ " \"queryType\": \"groupBy\",",
+ " \"dataSource\": \"test_datasource\",",
+ " \"granularity\": \"ALL\",",
+ " \"dimensions\": [],",
+ " \"aggregations\": [",
+ " {\"type\": \"buildTDigestSketch\", \"name\": \"sketch\",
\"fieldName\": \"value\", \"compression\": 200}",
+ " ],",
+ " \"postAggregations\": [",
+ " {\"type\": \"quantilesFromTDigestSketch\", \"name\":
\"quantiles\", \"fractions\": [0, 0.5, 1], \"field\": {\"type\":
\"fieldAccess\", \"fieldName\": \"sketch\"}}",
+ " ],",
+ " \"intervals\":
[\"2016-01-01T00:00:00.000Z/2016-01-31T00:00:00.000Z\"]",
+ "}"
+ )
+ );
+ List<Row> results = seq.toList();
+ Assert.assertEquals(1, results.size());
+ Row row = results.get(0);
+
+
+ // post agg
+ Object quantilesObject = row.getRaw("quantiles");
+ Assert.assertTrue(quantilesObject instanceof double[]);
+ double[] quantiles = (double[]) quantilesObject;
+ Assert.assertEquals(0, quantiles[0], 0.05); // min value
+ Assert.assertEquals(0.5, quantiles[1], 0.05); // median value
+ Assert.assertEquals(1, quantiles[2], 0.05); // max value
+ }
+
+ @Test
+ public void testIngestingSketches() throws Exception
+ {
+ Sequence<Row> seq = helper.createIndexAndRunQueryOnSegment(
+ new
File(this.getClass().getClassLoader().getResource("doubles_sketch_data.tsv").getFile()),
+ String.join(
+ "\n",
+ "{",
+ " \"type\": \"string\",",
+ " \"parseSpec\": {",
+ " \"format\": \"tsv\",",
+ " \"timestampSpec\": {\"column\": \"timestamp\", \"format\":
\"yyyyMMddHH\"},",
+ " \"dimensionsSpec\": {",
+ " \"dimensions\": [\"product\"],",
+ " \"dimensionExclusions\": [],",
+ " \"spatialDimensions\": []",
+ " },",
+ " \"columns\": [\"timestamp\", \"product\", \"sketch\"]",
+ " }",
+ "}"
+ ),
+ String.join(
+ "\n",
+ "[",
+ " {\"type\": \"mergeTDigestSketch\", \"name\":
\"first_level_merge_sketch\", \"fieldName\": \"sketch\", "
+ + "\"compression\": "
+ + "200}",
+ "]"
+ ),
+ 0, // minTimestamp
+ Granularities.NONE,
+ 10, // maxRowCount
+ String.join(
+ "\n",
+ "{",
+ " \"queryType\": \"groupBy\",",
+ " \"dataSource\": \"test_datasource\",",
+ " \"granularity\": \"ALL\",",
+ " \"dimensions\": [],",
+ " \"aggregations\": [",
+ " {\"type\": \"mergeTDigestSketch\", \"name\":
\"second_level_merge_sketch\", \"fieldName\": "
+ + "\"first_level_merge_sketch\", \"compression\": "
+ + "200}",
+ " ],",
+ " \"postAggregations\": [",
+ " {\"type\": \"quantilesFromTDigestSketch\", \"name\":
\"quantiles\", \"fractions\": [0, 0.5, 1], \"field\": {\"type\":
\"fieldAccess\", \"fieldName\": \"second_level_merge_sketch\"}}",
+ " ],",
+ " \"intervals\":
[\"2016-01-01T00:00:00.000Z/2016-01-31T00:00:00.000Z\"]",
+ "}"
+ )
+ );
+ List<Row> results = seq.toList();
+ Assert.assertEquals(1, results.size());
+ Row row = results.get(0);
+
+ // post agg
+ Object quantilesObject = row.getRaw("quantiles");
+ Assert.assertTrue(quantilesObject instanceof double[]);
+ double[] quantiles = (double[]) quantilesObject;
+ Assert.assertEquals(0, quantiles[0], 0.05); // min value
+ Assert.assertEquals(0.5, quantiles[1], 0.05); // median value
+ Assert.assertEquals(1, quantiles[2], 0.05); // max value
+ }
+}
diff --git
a/extensions-contrib/tdigestsketch/src/test/resources/doubles_build_data.tsv
b/extensions-contrib/tdigestsketch/src/test/resources/doubles_build_data.tsv
new file mode 100644
index 0000000..56eda05
--- /dev/null
+++ b/extensions-contrib/tdigestsketch/src/test/resources/doubles_build_data.tsv
@@ -0,0 +1,400 @@
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diff --git
a/extensions-contrib/tdigestsketch/src/test/resources/doubles_sketch_data.tsv
b/extensions-contrib/tdigestsketch/src/test/resources/doubles_sketch_data.tsv
new file mode 100644
index 0000000..f1f0bb8
--- /dev/null
+++
b/extensions-contrib/tdigestsketch/src/test/resources/doubles_sketch_data.tsv
@@ -0,0 +1,20 @@
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diff --git a/pom.xml b/pom.xml
index b65ab7a..44d93a1 100644
--- a/pom.xml
+++ b/pom.xml
@@ -174,6 +174,7 @@
<module>extensions-contrib/materialized-view-selection</module>
<module>extensions-contrib/momentsketch</module>
<module>extensions-contrib/moving-average-query</module>
+ <module>extensions-contrib/tdigestsketch</module>
<!-- distribution packaging -->
<module>distribution</module>
</modules>
diff --git
a/processing/src/main/java/org/apache/druid/query/aggregation/AggregatorUtil.java
b/processing/src/main/java/org/apache/druid/query/aggregation/AggregatorUtil.java
index dddafba..bf1edd2 100644
---
a/processing/src/main/java/org/apache/druid/query/aggregation/AggregatorUtil.java
+++
b/processing/src/main/java/org/apache/druid/query/aggregation/AggregatorUtil.java
@@ -121,6 +121,11 @@ public class AggregatorUtil
public static final byte MOMENTS_SKETCH_BUILD_CACHE_TYPE_ID = 0x36;
public static final byte MOMENTS_SKETCH_MERGE_CACHE_TYPE_ID = 0x37;
+ // TDigest sketch aggregators
+ public static final byte TDIGEST_BUILD_SKETCH_CACHE_TYPE_ID = 0x38;
+ public static final byte TDIGEST_MERGE_SKETCH_CACHE_TYPE_ID = 0x39;
+ public static final byte TDIGEST_SKETCH_TO_QUANTILES_CACHE_TYPE_ID = 0x40;
+
/**
* returns the list of dependent postAggregators that should be calculated
in order to calculate given postAgg
*
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