Materialized view implementation

distribution/pom.xml

@@ -243,6 +243,10 @@
                                         <argument>io.druid.extensions.contrib:druid-time-min-max</argument>
                                         <argument>-c</argument>
                                         <argument>io.druid.extensions.contrib:druid-virtual-columns</argument>
+                                        <argument>-c</argument>
+                                        <argument>io.druid.extensions.contrib:materialized-view-maintenance</argument>
+                                        <argument>-c</argument>
+                                        <argument>io.druid.extensions.contrib:materialized-view-selection</argument>
                                     </arguments>
                                 </configuration>
                             </execution>

docs/content/development/extensions-contrib/materialized-view.md

@@ -0,0 +1,114 @@
+---
+layout: doc_page
+---
+
+# Materialized View
+
+To use this feature, make sure to only load materialized-view-selection on broker and load materialized-view-maintenance on overlord. In addtion, this feature currently requires a hadoop cluster.
+
+This feature enables Druid to greatly improve the query performance, especially when the query dataSource has a very large number of dimensions but the query only required several dimensions. This feature includes two parts. One is `materialized-view-maintenance`, and the other is `materialized-view-selection`.
+
+## Materialized-view-maintenance
+In materialized-view-maintenance, dataSouces user ingested are called "base-dataSource". For each base-dataSource, we can submit `derivativeDataSource` supervisors to create and maintain other dataSources which we called  "derived-dataSource". The deminsions and metrics of derived-dataSources are the subset of base-dataSource's.
+The `derivativeDataSource` supervisor is used to keep the timeline of derived-dataSource consistent with base-dataSource. Each `derivativeDataSource` supervisor  is responsible for one derived-dataSource.
+
+A sample derivativeDataSource supervisor spec is shown below:
+```json
+   {
+       "type": "derivativeDataSource",
+       "baseDataSource": "wikiticker",
+       "dimensionsSpec": {
+           "dimensions": [
+               "isUnpatrolled",
+               "metroCode",
+               "namespace",
+               "page",
+               "regionIsoCode",
+               "regionName",
+               "user"
+           ]
+       },
+       "metricsSpec": [
+           {
+               "name": "count",
+               "type": "count"
+           },
+           {
+               "name": "added",
+               "type": "longSum",
+               "fieldName": "added"
+           }
+       ],
+       "tuningConfig": {
+           "type": "hadoop"
+       }
+   }
+```
+
+**Supervisor Configuration**
+
+|Field|Description|Required|
+|--------|-----------|---------|
+|Type	|The supervisor type. This should always be derivativeDataSource	|yes|
+|baseDataSource	|The name of base dataSource. This dataSource data should be already stored inside Druid, and the dataSource will be used as input data. See [dataSource inputSpec](http://druid.io/docs/latest/ingestion/update-existing-data.html#datasource "dataSource inputSpec"). 	|yes|
+|dimensionsSpec	|Specifies the dimensions of the data. These dimensions must be the subset of baseDataSource's dimensions.	|yes|
+|metricsSpec	|A list of aggregators. These metrics must be the subset of baseDataSource's metrics. See [aggregations](http://druid.io/docs/latest/querying/aggregations.html "aggregations") 	|yes|
+|tuningConfig	|TuningConfig must be HadoopTuningConfig. See [hadoop tuning config]( http://druid.io/docs/latest/ingestion/batch-ingestion.html#tuningconfig "hadoop tuning config")	|yes|
+|dataSource	|The name of this derived dataSource. 	|no(default=baseDataSource-hashCode of supervisor)|
+|hadoopDependencyCoordinates	|A JSON array of Hadoop dependency coordinates that Druid will use, this property will override the default Hadoop coordinates. Once specified, Druid will look for those Hadoop dependencies from the location specified by druid.extensions.hadoopDependenciesDir	|no|
+|classpathPrefix	|Classpath that will be pre-appended for the peon process.	|no|
+|context	|See below.	|no|
+
+**Context**
+
+|Field|Description|Required|
+|--------|-----------|---------|
+|maxTaskCount |The max number of tasks the supervisor can submit simultaneously.	|no(default=1)|
+
+##  Materialized-view-selection
+
+In materialized-view-selection, we implement a new query type `view`. When we request a view query, Druid will try its best to optimize the query based on query dataSource and intervals.
+
+A sample view query spec is shown below:
+```json
+   {
+       "queryType": "view",
+       "query": {
+           "queryType": "groupBy",
+           "dataSource": "wikiticker",
+           "granularity": "all",
+           "dimensions": [
+               "user"
+           ],
+           "limitSpec": {
+               "type": "default",
+               "limit": 1,
+               "columns": [
+                   {
+                       "dimension": "added",
+                       "direction": "descending",
+                       "dimensionOrder": "numeric"
+                   }
+               ]
+           },
+           "aggregations": [
+               {
+                   "type": "longSum",
+                   "name": "added",
+                   "fieldName": "added"
+               }
+           ],
+           "intervals": [
+               "2015-09-12/2015-09-13"
+           ]
+       }
+   }
+```
+There are 2 parts in a view query:
+
+|Field|Description|Required|
+|--------|-----------|---------|
+|queryType	|The query type. This should always be view	|yes|
+|query	|The real query of this `view` query. The real query must be [groupby](http://druid.io/docs/latest/querying/groupbyquery.html "groupby")/[topn](http://druid.io/docs/latest/querying/topnquery.html "topn")/[timeseries](http://druid.io/docs/latest/querying/timeseriesquery.html "timeseries") type.	|yes|
+
+**Note that Materialized View is currently designated as experimental. Please make sure the time of all nodes are the same and increase monotonically. Otherwise, some unexpected errors may happen on query results.**

extensions-contrib/materialized-view-maintenance/pom.xml

@@ -0,0 +1,70 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Licensed to Metamarkets Group Inc. (Metamarkets) under one
+  ~ or more contributor license agreements. See the NOTICE file
+  ~ distributed with this work for additional information
+  ~ regarding copyright ownership. Metamarkets 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>io.druid</groupId>
+        <version>0.13.0-SNAPSHOT</version>
+        <relativePath>../../pom.xml</relativePath>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>io.druid.extensions.contrib</groupId>
+    <artifactId>materialized-view-maintenance</artifactId>
+    <name>materialized-view-maintenance</name>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.druid</groupId>
+            <artifactId>druid-server</artifactId>
+            <version>${project.parent.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.druid</groupId>
+            <artifactId>druid-indexing-service</artifactId>
+            <version>${project.parent.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.druid</groupId>
+            <artifactId>druid-server</artifactId>
+            <version>${project.parent.version}</version>
+            <scope>test</scope>
+            <type>test-jar</type>
+        </dependency>
+        <dependency>
+            <groupId>io.druid</groupId>
+            <artifactId>druid-processing</artifactId>
+            <version>${project.parent.version}</version>
+            <scope>test</scope>
+            <type>test-jar</type>
+        </dependency>
+        <dependency>
+            <groupId>org.easymock</groupId>
+            <artifactId>easymock</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+</project>

extensions-contrib/materialized-view-maintenance/src/main/java/io/druid/indexing/materializedview/DerivativeDataSourceMetadata.java

@@ -0,0 +1,129 @@
+/*
+ * Licensed to Metamarkets Group Inc. (Metamarkets) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. Metamarkets 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 io.druid.indexing.materializedview;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Sets;
+import io.druid.indexing.overlord.DataSourceMetadata;
+
+import java.util.Objects;
+import java.util.Set;
+
+public class DerivativeDataSourceMetadata implements DataSourceMetadata 
+{
+  private final String baseDataSource;
+  private final Set<String> dimensions;
+  private final Set<String> metrics;
+
+  @JsonCreator
+  public DerivativeDataSourceMetadata(
+      @JsonProperty("baseDataSource") String baseDataSource,
+      @JsonProperty("dimensions") Set<String> dimensions,
+      @JsonProperty("metrics") Set<String> metrics
+  )
+  {
+    this.baseDataSource = Preconditions.checkNotNull(baseDataSource, "baseDataSource cannot be null. This is not a valid DerivativeDataSourceMetadata.");
+    this.dimensions = Preconditions.checkNotNull(dimensions, "dimensions cannot be null. This is not a valid DerivativeDataSourceMetadata.");
+    this.metrics = Preconditions.checkNotNull(metrics, "metrics cannot be null. This is not a valid DerivativeDataSourceMetadata.");
+  }
+
+  @JsonProperty("baseDataSource")
+  public String getBaseDataSource()
+  {
+    return baseDataSource;
+  }
+
+  @JsonProperty("dimensions")
+  public Set<String> getDimensions()
+  {
+    return dimensions;
+  }
+
+  @JsonProperty("metrics")
+  public Set<String> getMetrics()
+  {
+    return metrics;
+  }
+
+  @Override
+  public boolean isValidStart()
+  {
+    return false;
+  }
+
+  @Override
+  public boolean matches(DataSourceMetadata other) 
+  {
+    return equals(other);
+  }
+
+  @Override
+  public DataSourceMetadata plus(DataSourceMetadata other)
+  {
+    throw new UnsupportedOperationException("Derivative dataSource metadata is not allowed to plus");
+  }
+
+  @Override
+  public DataSourceMetadata minus(DataSourceMetadata other) 
+  {
+    throw new UnsupportedOperationException("Derivative dataSource metadata is not allowed to minus");
+  }
+
+  @Override
+  public boolean equals(Object o)
+  {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    DerivativeDataSourceMetadata that = (DerivativeDataSourceMetadata) o;
+
+    return baseDataSource.equals(that.getBaseDataSource()) && 
+        dimensions.equals(that.getDimensions()) &&
+        metrics.equals(that.getMetrics());
+  }
+
+  @Override
+  public int hashCode()
+  {
+    return Objects.hash(baseDataSource, dimensions, metrics);
+  }
+
+  public Set<String> getColumns()
+  {
+    Set<String> fields = Sets.newHashSet(dimensions);
+    fields.addAll(metrics);
+    return fields;
+  }
+
+  @Override
+  public String toString()
+  {
+    return "DerivedDataSourceMetadata{" +
+        "baseDataSource=" + baseDataSource +
+        ", dimensions=" + dimensions +
+        ", metrics=" + metrics +
+        '}';
+  }
+}

extensions-contrib/materialized-view-maintenance/src/main/java/io/druid/indexing/materializedview/MaterializedViewMaintenanceDruidModule.java

@@ -0,0 +1,51 @@
+/*
+ * Licensed to Metamarkets Group Inc. (Metamarkets) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. Metamarkets 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 io.druid.indexing.materializedview;
+
+import com.fasterxml.jackson.databind.Module;
+import com.fasterxml.jackson.databind.jsontype.NamedType;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.google.common.collect.ImmutableList;
+import com.google.inject.Binder;
+import io.druid.guice.JsonConfigProvider;
+import io.druid.initialization.DruidModule;
+
+import java.util.List;
+
+public class MaterializedViewMaintenanceDruidModule implements DruidModule 
+{
+  @Override
+  public List<? extends Module> getJacksonModules() 
+  {
+    return ImmutableList.of(
+        new SimpleModule(getClass().getSimpleName())
+            .registerSubtypes(
+                new NamedType(MaterializedViewSupervisorSpec.class, "derivativeDataSource"),
+                new NamedType(DerivativeDataSourceMetadata.class, "derivativeDataSource")
+                )
+    );
+  }
+
+  @Override
+  public void configure(Binder binder)
+  {
+    JsonConfigProvider.bind(binder, "druid.materialized.view.task", MaterializedViewTaskConfig.class);
+  }
+}