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Aggregations Refactor: Refactor Sampler Aggregation

This commit is contained in:
Colin Goodheart-Smithe 2015-12-14 11:54:41 +00:00
parent 8f63c46d27
commit 1aea0faa86
14 changed files with 839 additions and 274 deletions
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2
core/src/main/java/org/elasticsearch/search/SearchModule.java
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@ -55,6 +55,7 @@ import org.elasticsearch.search.aggregations.bucket.range.geodistance.GeoDistanc
import org.elasticsearch.search.aggregations.bucket.range.geodistance.InternalGeoDistance;
import org.elasticsearch.search.aggregations.bucket.range.ipv4.InternalIPv4Range;
import org.elasticsearch.search.aggregations.bucket.range.ipv4.IpRangeParser;
import org.elasticsearch.search.aggregations.bucket.sampler.DiversifiedSamplerParser;
import org.elasticsearch.search.aggregations.bucket.sampler.InternalSampler;
import org.elasticsearch.search.aggregations.bucket.sampler.SamplerParser;
import org.elasticsearch.search.aggregations.bucket.sampler.UnmappedSampler;
@ -264,6 +265,7 @@ public class SearchModule extends AbstractModule {
multibinderAggParser.addBinding().to(FilterParser.class);
multibinderAggParser.addBinding().to(FiltersParser.class);
multibinderAggParser.addBinding().to(SamplerParser.class);
multibinderAggParser.addBinding().to(DiversifiedSamplerParser.class);
multibinderAggParser.addBinding().to(TermsParser.class);
multibinderAggParser.addBinding().to(SignificantTermsParser.class);
multibinderAggParser.addBinding().to(RangeParser.class);

79
core/src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/DiversifiedSamplerAggregationBuilder.java Normal file
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@ -0,0 +1,79 @@
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.search.aggregations.bucket.sampler;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.search.aggregations.ValuesSourceAggregationBuilder;
import java.io.IOException;
/**
* Builder for the {@link Sampler} aggregation.
*/
public class DiversifiedSamplerAggregationBuilder extends ValuesSourceAggregationBuilder<DiversifiedSamplerAggregationBuilder> {
private int shardSize = SamplerAggregator.Factory.DEFAULT_SHARD_SAMPLE_SIZE;
int maxDocsPerValue = SamplerAggregator.DiversifiedFactory.MAX_DOCS_PER_VALUE_DEFAULT;
String executionHint = null;
/**
* Sole constructor.
*/
public DiversifiedSamplerAggregationBuilder(String name) {
super(name, SamplerAggregator.DiversifiedFactory.TYPE.name());
}
/**
* Set the max num docs to be returned from each shard.
*/
public DiversifiedSamplerAggregationBuilder shardSize(int shardSize) {
this.shardSize = shardSize;
return this;
}
public DiversifiedSamplerAggregationBuilder maxDocsPerValue(int maxDocsPerValue) {
this.maxDocsPerValue = maxDocsPerValue;
return this;
}
public DiversifiedSamplerAggregationBuilder executionHint(String executionHint) {
this.executionHint = executionHint;
return this;
}
@Override
protected XContentBuilder doInternalXContent(XContentBuilder builder, Params params) throws IOException {
if (shardSize != SamplerAggregator.Factory.DEFAULT_SHARD_SAMPLE_SIZE) {
builder.field(SamplerAggregator.SHARD_SIZE_FIELD.getPreferredName(), shardSize);
}
if (maxDocsPerValue != SamplerAggregator.DiversifiedFactory.MAX_DOCS_PER_VALUE_DEFAULT) {
builder.field(SamplerAggregator.MAX_DOCS_PER_VALUE_FIELD.getPreferredName(), maxDocsPerValue);
}
if (executionHint != null) {
builder.field(SamplerAggregator.EXECUTION_HINT_FIELD.getPreferredName(), executionHint);
}
return builder;
}
}

97
core/src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/DiversifiedSamplerParser.java Normal file
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@ -0,0 +1,97 @@
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.search.aggregations.bucket.sampler;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.ParseFieldMatcher;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.search.aggregations.AggregatorFactory;
import org.elasticsearch.search.aggregations.support.AbstractValuesSourceParser.AnyValuesSourceParser;
import org.elasticsearch.search.aggregations.support.ValueType;
import org.elasticsearch.search.aggregations.support.ValuesSource;
import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
import org.elasticsearch.search.aggregations.support.ValuesSourceType;
import java.io.IOException;
import java.util.Map;
/**
*
*/
public class DiversifiedSamplerParser extends AnyValuesSourceParser {
public DiversifiedSamplerParser() {
super(true, false);
}
@Override
public String type() {
return SamplerAggregator.DiversifiedFactory.TYPE.name();
}
@Override
protected ValuesSourceAggregatorFactory<ValuesSource> createFactory(String aggregationName, ValuesSourceType valuesSourceType,
ValueType targetValueType, Map<ParseField, Object> otherOptions) {
SamplerAggregator.DiversifiedFactory factory = new SamplerAggregator.DiversifiedFactory(aggregationName, valuesSourceType,
targetValueType);
Integer shardSize = (Integer) otherOptions.get(SamplerAggregator.SHARD_SIZE_FIELD);
if (shardSize != null) {
factory.shardSize(shardSize);
}
Integer maxDocsPerValue = (Integer) otherOptions.get(SamplerAggregator.MAX_DOCS_PER_VALUE_FIELD);
if (maxDocsPerValue != null) {
factory.maxDocsPerValue(maxDocsPerValue);
}
String executionHint = (String) otherOptions.get(SamplerAggregator.EXECUTION_HINT_FIELD);
if (executionHint != null) {
factory.executionHint(executionHint);
}
return factory;
}
@Override
protected boolean token(String aggregationName, String currentFieldName, XContentParser.Token token, XContentParser parser,
ParseFieldMatcher parseFieldMatcher, Map<ParseField, Object> otherOptions) throws IOException {
if (token == XContentParser.Token.VALUE_NUMBER) {
if (parseFieldMatcher.match(currentFieldName, SamplerAggregator.SHARD_SIZE_FIELD)) {
int shardSize = parser.intValue();
otherOptions.put(SamplerAggregator.SHARD_SIZE_FIELD, shardSize);
return true;
} else if (parseFieldMatcher.match(currentFieldName, SamplerAggregator.MAX_DOCS_PER_VALUE_FIELD)) {
int maxDocsPerValue = parser.intValue();
otherOptions.put(SamplerAggregator.MAX_DOCS_PER_VALUE_FIELD, maxDocsPerValue);
return true;
}
} else if (token == XContentParser.Token.VALUE_STRING) {
if (parseFieldMatcher.match(currentFieldName, SamplerAggregator.EXECUTION_HINT_FIELD)) {
String executionHint = parser.text();
otherOptions.put(SamplerAggregator.EXECUTION_HINT_FIELD, executionHint);
return true;
}
}
return false;
}
@Override
public AggregatorFactory[] getFactoryPrototypes() {
return new AggregatorFactory[] { new SamplerAggregator.DiversifiedFactory(null, null, null) };
}
}

27
core/src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/SamplerAggregationBuilder.java
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@ -29,10 +29,7 @@ import java.io.IOException;
*/
public class SamplerAggregationBuilder extends ValuesSourceAggregationBuilder<SamplerAggregationBuilder> {
private int shardSize = SamplerParser.DEFAULT_SHARD_SAMPLE_SIZE;
int maxDocsPerValue = SamplerParser.MAX_DOCS_PER_VALUE_DEFAULT;
String executionHint = null;
private int shardSize = SamplerAggregator.Factory.DEFAULT_SHARD_SAMPLE_SIZE;
/**
* Sole constructor.
@ -49,28 +46,10 @@ public class SamplerAggregationBuilder extends ValuesSourceAggregationBuilder<Sa
return this;
}
public SamplerAggregationBuilder maxDocsPerValue(int maxDocsPerValue) {
this.maxDocsPerValue = maxDocsPerValue;
return this;
}
public SamplerAggregationBuilder executionHint(String executionHint) {
this.executionHint = executionHint;
return this;
}
@Override
protected XContentBuilder doInternalXContent(XContentBuilder builder, Params params) throws IOException {
// builder.startObject();
if (shardSize != SamplerParser.DEFAULT_SHARD_SAMPLE_SIZE) {
builder.field(SamplerParser.SHARD_SIZE_FIELD.getPreferredName(), shardSize);
}
if (maxDocsPerValue != SamplerParser.MAX_DOCS_PER_VALUE_DEFAULT) {
builder.field(SamplerParser.MAX_DOCS_PER_VALUE_FIELD.getPreferredName(), maxDocsPerValue);
}
if (executionHint != null) {
builder.field(SamplerParser.EXECUTION_HINT_FIELD.getPreferredName(), executionHint);
if (shardSize != SamplerAggregator.Factory.DEFAULT_SHARD_SAMPLE_SIZE) {
builder.field(SamplerAggregator.SHARD_SIZE_FIELD.getPreferredName(), shardSize);
}
return builder;

154
core/src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/SamplerAggregator.java
View File

@ -21,12 +21,16 @@ package org.elasticsearch.search.aggregations.bucket.sampler;
import org.apache.lucene.index.LeafReaderContext;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.ParseFieldMatcher;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.lease.Releasables;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.search.aggregations.AggregationExecutionException;
import org.elasticsearch.search.aggregations.Aggregator;
import org.elasticsearch.search.aggregations.AggregatorFactories;
import org.elasticsearch.search.aggregations.AggregatorFactory;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.InternalAggregation.Type;
import org.elasticsearch.search.aggregations.LeafBucketCollector;
import org.elasticsearch.search.aggregations.NonCollectingAggregator;
import org.elasticsearch.search.aggregations.bucket.BestDocsDeferringCollector;
@ -34,14 +38,16 @@ import org.elasticsearch.search.aggregations.bucket.DeferringBucketCollector;
import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregator;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
import org.elasticsearch.search.aggregations.support.AggregationContext;
import org.elasticsearch.search.aggregations.support.ValueType;
import org.elasticsearch.search.aggregations.support.ValuesSource;
import org.elasticsearch.search.aggregations.support.ValuesSource.Numeric;
import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
import org.elasticsearch.search.aggregations.support.ValuesSourceParser;
import org.elasticsearch.search.aggregations.support.ValuesSourceType;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Objects;
/**
* Aggregate on only the top-scoring docs on a shard.
@ -55,6 +61,10 @@ import java.util.Map;
*/
public class SamplerAggregator extends SingleBucketAggregator {
public static final ParseField SHARD_SIZE_FIELD = new ParseField("shard_size");
public static final ParseField MAX_DOCS_PER_VALUE_FIELD = new ParseField("max_docs_per_value");
public static final ParseField EXECUTION_HINT_FIELD = new ParseField("execution_hint");
public enum ExecutionMode {
@ -182,34 +192,123 @@ public class SamplerAggregator extends SingleBucketAggregator {
public static class Factory extends AggregatorFactory {
private int shardSize;
public static final int DEFAULT_SHARD_SAMPLE_SIZE = 100;
public Factory(String name, int shardSize) {
private int shardSize = DEFAULT_SHARD_SAMPLE_SIZE;
public Factory(String name) {
super(name, InternalSampler.TYPE);
}
/**
* Set the max num docs to be returned from each shard.
*/
public void shardSize(int shardSize) {
this.shardSize = shardSize;
}
/**
* Get the max num docs to be returned from each shard.
*/
public int shardSize() {
return shardSize;
}
@Override
public Aggregator createInternal(AggregationContext context, Aggregator parent, boolean collectsFromSingleBucket,
List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
return new SamplerAggregator(name, shardSize, factories, context, parent, pipelineAggregators, metaData);
}
@Override
protected XContentBuilder internalXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject();
builder.field(SHARD_SIZE_FIELD.getPreferredName(), shardSize);
builder.endObject();
return builder;
}
@Override
protected AggregatorFactory doReadFrom(String name, StreamInput in) throws IOException {
Factory factory = new Factory(name);
factory.shardSize = in.readVInt();
return factory;
}
@Override
protected void doWriteTo(StreamOutput out) throws IOException {
out.writeVInt(shardSize);
}
@Override
protected int doHashCode() {
return Objects.hash(shardSize);
}
@Override
protected boolean doEquals(Object obj) {
Factory other = (Factory) obj;
return Objects.equals(shardSize, other.shardSize);
}
}
public static class DiversifiedFactory extends ValuesSourceAggregatorFactory<ValuesSource> {
private int shardSize;
private int maxDocsPerValue;
private String executionHint;
public static final Type TYPE = new Type("diversified_sampler");
public DiversifiedFactory(String name, int shardSize, String executionHint, ValuesSourceParser.Input vsInput, int maxDocsPerValue) {
super(name, InternalSampler.TYPE, vsInput);
public static final int MAX_DOCS_PER_VALUE_DEFAULT = 1;
private int shardSize = Factory.DEFAULT_SHARD_SAMPLE_SIZE;
private int maxDocsPerValue = MAX_DOCS_PER_VALUE_DEFAULT;
private String executionHint = null;
public DiversifiedFactory(String name, ValuesSourceType valueSourceType, ValueType valueType) {
super(name, TYPE, valueSourceType, valueType);
}
/**
* Set the max num docs to be returned from each shard.
*/
public void shardSize(int shardSize) {
this.shardSize = shardSize;
}
/**
* Get the max num docs to be returned from each shard.
*/
public int shardSize() {
return shardSize;
}
/**
* Set the max num docs to be returned per value.
*/
public void maxDocsPerValue(int maxDocsPerValue) {
this.maxDocsPerValue = maxDocsPerValue;
}
/**
* Get the max num docs to be returned per value.
*/
public int maxDocsPerValue() {
return maxDocsPerValue;
}
/**
* Set the execution hint.
*/
public void executionHint(String executionHint) {
this.executionHint = executionHint;
}
/**
* Get the execution hint.
*/
public String executionHint() {
return executionHint;
}
@Override
protected Aggregator doCreateInternal(ValuesSource valuesSource, AggregationContext context, Aggregator parent,
boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
@ -256,6 +355,45 @@ public class SamplerAggregator extends SingleBucketAggregator {
};
}
@Override
protected XContentBuilder doXContentBody(XContentBuilder builder, Params params) throws IOException {
builder.field(SHARD_SIZE_FIELD.getPreferredName(), shardSize);
builder.field(MAX_DOCS_PER_VALUE_FIELD.getPreferredName(), maxDocsPerValue);
if (executionHint != null) {
builder.field(EXECUTION_HINT_FIELD.getPreferredName(), executionHint);
}
return builder;
}
@Override
protected ValuesSourceAggregatorFactory<ValuesSource> innerReadFrom(String name, ValuesSourceType valuesSourceType,
ValueType targetValueType, StreamInput in) throws IOException {
DiversifiedFactory factory = new DiversifiedFactory(name, valuesSourceType, targetValueType);
factory.shardSize = in.readVInt();
factory.maxDocsPerValue = in.readVInt();
factory.executionHint = in.readOptionalString();
return factory;
}
@Override
protected void innerWriteTo(StreamOutput out) throws IOException {
out.writeVInt(shardSize);
out.writeVInt(maxDocsPerValue);
out.writeOptionalString(executionHint);
}
@Override
protected int innerHashCode() {
return Objects.hash(shardSize, maxDocsPerValue, executionHint);
}
@Override
protected boolean innerEquals(Object obj) {
DiversifiedFactory other = (DiversifiedFactory) obj;
return Objects.equals(shardSize, other.shardSize)
&& Objects.equals(maxDocsPerValue, other.maxDocsPerValue)
&& Objects.equals(executionHint, other.executionHint);
}
}
@Override

61
core/src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/SamplerParser.java
View File

@ -18,12 +18,11 @@
*/
package org.elasticsearch.search.aggregations.bucket.sampler;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.ParsingException;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.search.SearchParseException;
import org.elasticsearch.search.aggregations.Aggregator;
import org.elasticsearch.search.aggregations.AggregatorFactory;
import org.elasticsearch.search.aggregations.support.ValuesSourceParser;
import org.elasticsearch.search.internal.SearchContext;
import java.io.IOException;
@ -33,14 +32,6 @@ import java.io.IOException;
*/
public class SamplerParser implements Aggregator.Parser {
public static final int DEFAULT_SHARD_SAMPLE_SIZE = 100;
public static final ParseField SHARD_SIZE_FIELD = new ParseField("shard_size");
public static final ParseField MAX_DOCS_PER_VALUE_FIELD = new ParseField("max_docs_per_value");
public static final ParseField EXECUTION_HINT_FIELD = new ParseField("execution_hint");
public static final boolean DEFAULT_USE_GLOBAL_ORDINALS = false;
public static final int MAX_DOCS_PER_VALUE_DEFAULT = 1;
@Override
public String type() {
return InternalSampler.TYPE.name();
@ -51,60 +42,34 @@ public class SamplerParser implements Aggregator.Parser {
XContentParser.Token token;
String currentFieldName = null;
String executionHint = null;
int shardSize = DEFAULT_SHARD_SAMPLE_SIZE;
int maxDocsPerValue = MAX_DOCS_PER_VALUE_DEFAULT;
ValuesSourceParser vsParser = null;
boolean diversityChoiceMade = false;
vsParser = ValuesSourceParser.any(aggregationName, InternalSampler.TYPE, context).scriptable(true).formattable(false).build();
Integer shardSize = null;
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
currentFieldName = parser.currentName();
} else if (vsParser.token(currentFieldName, token, parser)) {
continue;
} else if (token == XContentParser.Token.VALUE_NUMBER) {
if (context.parseFieldMatcher().match(currentFieldName, SHARD_SIZE_FIELD)) {
if (context.parseFieldMatcher().match(currentFieldName, SamplerAggregator.SHARD_SIZE_FIELD)) {
shardSize = parser.intValue();
} else if (context.parseFieldMatcher().match(currentFieldName, MAX_DOCS_PER_VALUE_FIELD)) {
diversityChoiceMade = true;
maxDocsPerValue = parser.intValue();
} else {
throw new SearchParseException(context, "Unsupported property \"" + currentFieldName + "\" for aggregation \""
+ aggregationName, parser.getTokenLocation());
}
} else if (!vsParser.token(currentFieldName, token, parser)) {
if (context.parseFieldMatcher().match(currentFieldName, EXECUTION_HINT_FIELD)) {
executionHint = parser.text();
} else {
throw new SearchParseException(context, "Unexpected token " + token + " in [" + aggregationName + "].",
parser.getTokenLocation());
throw new ParsingException(parser.getTokenLocation(),
"Unsupported property \"" + currentFieldName + "\" for aggregation \"" + aggregationName);
}
} else {
throw new SearchParseException(context, "Unsupported property \"" + currentFieldName + "\" for aggregation \""
+ aggregationName, parser.getTokenLocation());
throw new ParsingException(parser.getTokenLocation(),
"Unsupported property \"" + currentFieldName + "\" for aggregation \"" + aggregationName);
}
}
ValuesSourceParser.Input vsInput = vsParser.input();
if (vsInput.valid()) {
return new SamplerAggregator.DiversifiedFactory(aggregationName, shardSize, executionHint, vsInput, maxDocsPerValue);
} else {
if (diversityChoiceMade) {
throw new SearchParseException(context, "Sampler aggregation has " + MAX_DOCS_PER_VALUE_FIELD.getPreferredName()
+ " setting but no \"field\" or \"script\" setting to provide values for aggregation \"" + aggregationName + "\"",
parser.getTokenLocation());
}
return new SamplerAggregator.Factory(aggregationName, shardSize);
SamplerAggregator.Factory factory = new SamplerAggregator.Factory(aggregationName);
if (shardSize != null) {
factory.shardSize(shardSize);
}
return factory;
}
// NORELEASE implement this method when refactoring this aggregation
@Override
public AggregatorFactory[] getFactoryPrototypes() {
return null;
return new AggregatorFactory[] { new SamplerAggregator.Factory(null) };
}
}

4
core/src/main/java/org/elasticsearch/search/aggregations/support/ValuesSourceAggregatorFactory.java
View File

@ -433,7 +433,7 @@ public abstract class ValuesSourceAggregatorFactory<VS extends ValuesSource> ext
}
@Override
public final int doHashCode() {
protected final int doHashCode() {
return Objects.hash(field, format, missing, script, targetValueType, timeZone, valueType, valuesSourceType,
innerHashCode());
}
@ -446,7 +446,7 @@ public abstract class ValuesSourceAggregatorFactory<VS extends ValuesSource> ext
}
@Override
public final boolean doEquals(Object obj) {
protected final boolean doEquals(Object obj) {
ValuesSourceAggregatorFactory<?> other = (ValuesSourceAggregatorFactory<?>) obj;
if (!Objects.equals(field, other.field))
return false;

238
core/src/test/java/org/elasticsearch/search/aggregations/bucket/DiversifiedSamplerIT.java Normal file
View File

@ -0,0 +1,238 @@
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.search.aggregations.bucket;
import org.elasticsearch.action.admin.indices.refresh.RefreshRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.action.search.SearchType;
import org.elasticsearch.index.query.TermQueryBuilder;
import org.elasticsearch.search.aggregations.bucket.sampler.DiversifiedSamplerAggregationBuilder;
import org.elasticsearch.search.aggregations.bucket.sampler.Sampler;
import org.elasticsearch.search.aggregations.bucket.sampler.SamplerAggregator;
import org.elasticsearch.search.aggregations.bucket.terms.Terms;
import org.elasticsearch.search.aggregations.bucket.terms.Terms.Bucket;
import org.elasticsearch.search.aggregations.bucket.terms.TermsBuilder;
import org.elasticsearch.search.aggregations.metrics.max.Max;
import org.elasticsearch.test.ESIntegTestCase;
import java.util.Collection;
import static org.elasticsearch.cluster.metadata.IndexMetaData.SETTING_NUMBER_OF_REPLICAS;
import static org.elasticsearch.cluster.metadata.IndexMetaData.SETTING_NUMBER_OF_SHARDS;
import static org.elasticsearch.search.aggregations.AggregationBuilders.max;
import static org.elasticsearch.search.aggregations.AggregationBuilders.sampler;
import static org.elasticsearch.search.aggregations.AggregationBuilders.terms;
import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertSearchResponse;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.greaterThan;
import static org.hamcrest.Matchers.greaterThanOrEqualTo;
import static org.hamcrest.Matchers.lessThanOrEqualTo;
/**
* Tests the Sampler aggregation
*/
@ESIntegTestCase.SuiteScopeTestCase
public class DiversifiedSamplerIT extends ESIntegTestCase {
public static final int NUM_SHARDS = 2;
public String randomExecutionHint() {
return randomBoolean() ? null : randomFrom(SamplerAggregator.ExecutionMode.values()).toString();
}
@Override
public void setupSuiteScopeCluster() throws Exception {
assertAcked(prepareCreate("test").setSettings(SETTING_NUMBER_OF_SHARDS, NUM_SHARDS, SETTING_NUMBER_OF_REPLICAS, 0).addMapping(
"book", "author", "type=string,index=not_analyzed", "name", "type=string,index=analyzed", "genre",
"type=string,index=not_analyzed", "price", "type=float"));
createIndex("idx_unmapped");
// idx_unmapped_author is same as main index but missing author field
assertAcked(prepareCreate("idx_unmapped_author").setSettings(SETTING_NUMBER_OF_SHARDS, NUM_SHARDS, SETTING_NUMBER_OF_REPLICAS, 0)
.addMapping("book", "name", "type=string,index=analyzed", "genre", "type=string,index=not_analyzed", "price", "type=float"));
ensureGreen();
String data[] = {
// "id,cat,name,price,inStock,author_t,series_t,sequence_i,genre_s",
"0553573403,book,A Game of Thrones,7.99,true,George R.R. Martin,A Song of Ice and Fire,1,fantasy",
"0553579908,book,A Clash of Kings,7.99,true,George R.R. Martin,A Song of Ice and Fire,2,fantasy",
"055357342X,book,A Storm of Swords,7.99,true,George R.R. Martin,A Song of Ice and Fire,3,fantasy",
"0553293354,book,Foundation,17.99,true,Isaac Asimov,Foundation Novels,1,scifi",
"0812521390,book,The Black Company,6.99,false,Glen Cook,The Chronicles of The Black Company,1,fantasy",
"0812550706,book,Ender's Game,6.99,true,Orson Scott Card,Ender,1,scifi",
"0441385532,book,Jhereg,7.95,false,Steven Brust,Vlad Taltos,1,fantasy",
"0380014300,book,Nine Princes In Amber,6.99,true,Roger Zelazny,the Chronicles of Amber,1,fantasy",
"0805080481,book,The Book of Three,5.99,true,Lloyd Alexander,The Chronicles of Prydain,1,fantasy",
"080508049X,book,The Black Cauldron,5.99,true,Lloyd Alexander,The Chronicles of Prydain,2,fantasy"
};
for (int i = 0; i < data.length; i++) {
String[] parts = data[i].split(",");
client().prepareIndex("test", "book", "" + i).setSource("author", parts[5], "name", parts[2], "genre", parts[8], "price",Float.parseFloat(parts[3])).get();
client().prepareIndex("idx_unmapped_author", "book", "" + i).setSource("name", parts[2], "genre", parts[8],"price",Float.parseFloat(parts[3])).get();
}
client().admin().indices().refresh(new RefreshRequest("test")).get();
}
public void testIssue10719() throws Exception {
// Tests that we can refer to nested elements under a sample in a path
// statement
boolean asc = randomBoolean();
SearchResponse response = client().prepareSearch("test").setTypes("book").setSearchType(SearchType.QUERY_AND_FETCH)
.addAggregation(terms("genres")
.field("genre")
.order(Terms.Order.aggregation("sample>max_price.value", asc))
.subAggregation(sampler("sample").shardSize(100)
.subAggregation(max("max_price").field("price")))
).execute().actionGet();
assertSearchResponse(response);
Terms genres = response.getAggregations().get("genres");
Collection<Bucket> genreBuckets = genres.getBuckets();
// For this test to be useful we need >1 genre bucket to compare
assertThat(genreBuckets.size(), greaterThan(1));
double lastMaxPrice = asc ? Double.MIN_VALUE : Double.MAX_VALUE;
for (Terms.Bucket genreBucket : genres.getBuckets()) {
Sampler sample = genreBucket.getAggregations().get("sample");
Max maxPriceInGenre = sample.getAggregations().get("max_price");
double price = maxPriceInGenre.getValue();
if (asc) {
assertThat(price, greaterThanOrEqualTo(lastMaxPrice));
} else {
assertThat(price, lessThanOrEqualTo(lastMaxPrice));
}
lastMaxPrice = price;
}
}
public void testSimpleDiversity() throws Exception {
int MAX_DOCS_PER_AUTHOR = 1;
DiversifiedSamplerAggregationBuilder sampleAgg = new DiversifiedSamplerAggregationBuilder("sample").shardSize(100);
sampleAgg.field("author").maxDocsPerValue(MAX_DOCS_PER_AUTHOR).executionHint(randomExecutionHint());
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
SearchResponse response = client().prepareSearch("test")
.setSearchType(SearchType.QUERY_AND_FETCH)
.setQuery(new TermQueryBuilder("genre", "fantasy"))
.setFrom(0).setSize(60)
.addAggregation(sampleAgg)
.execute()
.actionGet();
assertSearchResponse(response);
Sampler sample = response.getAggregations().get("sample");
Terms authors = sample.getAggregations().get("authors");
Collection<Bucket> testBuckets = authors.getBuckets();
for (Terms.Bucket testBucket : testBuckets) {
assertThat(testBucket.getDocCount(), lessThanOrEqualTo((long) NUM_SHARDS * MAX_DOCS_PER_AUTHOR));
}
}
public void testNestedDiversity() throws Exception {
// Test multiple samples gathered under buckets made by a parent agg
int MAX_DOCS_PER_AUTHOR = 1;
TermsBuilder rootTerms = new TermsBuilder("genres").field("genre");
DiversifiedSamplerAggregationBuilder sampleAgg = new DiversifiedSamplerAggregationBuilder("sample").shardSize(100);
sampleAgg.field("author").maxDocsPerValue(MAX_DOCS_PER_AUTHOR).executionHint(randomExecutionHint());
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
rootTerms.subAggregation(sampleAgg);
SearchResponse response = client().prepareSearch("test").setSearchType(SearchType.QUERY_AND_FETCH)
.addAggregation(rootTerms).execute().actionGet();
assertSearchResponse(response);
Terms genres = response.getAggregations().get("genres");
Collection<Bucket> genreBuckets = genres.getBuckets();
for (Terms.Bucket genreBucket : genreBuckets) {
Sampler sample = genreBucket.getAggregations().get("sample");
Terms authors = sample.getAggregations().get("authors");
Collection<Bucket> testBuckets = authors.getBuckets();
for (Terms.Bucket testBucket : testBuckets) {
assertThat(testBucket.getDocCount(), lessThanOrEqualTo((long) NUM_SHARDS * MAX_DOCS_PER_AUTHOR));
}
}
}
public void testNestedSamples() throws Exception {
// Test samples nested under samples
int MAX_DOCS_PER_AUTHOR = 1;
int MAX_DOCS_PER_GENRE = 2;
DiversifiedSamplerAggregationBuilder rootSample = new DiversifiedSamplerAggregationBuilder("genreSample").shardSize(100)
.field("genre")
.maxDocsPerValue(MAX_DOCS_PER_GENRE);
DiversifiedSamplerAggregationBuilder sampleAgg = new DiversifiedSamplerAggregationBuilder("sample").shardSize(100);
sampleAgg.field("author").maxDocsPerValue(MAX_DOCS_PER_AUTHOR).executionHint(randomExecutionHint());
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
sampleAgg.subAggregation(new TermsBuilder("genres").field("genre"));
rootSample.subAggregation(sampleAgg);
SearchResponse response = client().prepareSearch("test").setSearchType(SearchType.QUERY_AND_FETCH).addAggregation(rootSample)
.execute().actionGet();
assertSearchResponse(response);
Sampler genreSample = response.getAggregations().get("genreSample");
Sampler sample = genreSample.getAggregations().get("sample");
Terms genres = sample.getAggregations().get("genres");
Collection<Bucket> testBuckets = genres.getBuckets();
for (Terms.Bucket testBucket : testBuckets) {
assertThat(testBucket.getDocCount(), lessThanOrEqualTo((long) NUM_SHARDS * MAX_DOCS_PER_GENRE));
}
Terms authors = sample.getAggregations().get("authors");
testBuckets = authors.getBuckets();
for (Terms.Bucket testBucket : testBuckets) {
assertThat(testBucket.getDocCount(), lessThanOrEqualTo((long) NUM_SHARDS * MAX_DOCS_PER_AUTHOR));
}
}
public void testPartiallyUnmappedDiversifyField() throws Exception {
// One of the indexes is missing the "author" field used for
// diversifying results
DiversifiedSamplerAggregationBuilder sampleAgg = new DiversifiedSamplerAggregationBuilder("sample").shardSize(100).field("author")
.maxDocsPerValue(1);
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
SearchResponse response = client().prepareSearch("idx_unmapped_author", "test").setSearchType(SearchType.QUERY_AND_FETCH)
.setQuery(new TermQueryBuilder("genre", "fantasy")).setFrom(0).setSize(60).addAggregation(sampleAgg)
.execute().actionGet();
assertSearchResponse(response);
Sampler sample = response.getAggregations().get("sample");
assertThat(sample.getDocCount(), greaterThan(0l));
Terms authors = sample.getAggregations().get("authors");
assertThat(authors.getBuckets().size(), greaterThan(0));
}
public void testWhollyUnmappedDiversifyField() throws Exception {
//All of the indices are missing the "author" field used for diversifying results
int MAX_DOCS_PER_AUTHOR = 1;
DiversifiedSamplerAggregationBuilder sampleAgg = new DiversifiedSamplerAggregationBuilder("sample").shardSize(100);
sampleAgg.field("author").maxDocsPerValue(MAX_DOCS_PER_AUTHOR).executionHint(randomExecutionHint());
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
SearchResponse response = client().prepareSearch("idx_unmapped", "idx_unmapped_author").setSearchType(SearchType.QUERY_AND_FETCH)
.setQuery(new TermQueryBuilder("genre", "fantasy")).setFrom(0).setSize(60).addAggregation(sampleAgg).execute().actionGet();
assertSearchResponse(response);
Sampler sample = response.getAggregations().get("sample");
assertThat(sample.getDocCount(), equalTo(0l));
Terms authors = sample.getAggregations().get("authors");
assertNull(authors);
}
}

63
core/src/test/java/org/elasticsearch/search/aggregations/bucket/DiversifiedSamplerTests.java Normal file
View File

@ -0,0 +1,63 @@
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.search.aggregations.bucket;
import org.elasticsearch.script.Script;
import org.elasticsearch.search.aggregations.BaseAggregationTestCase;
import org.elasticsearch.search.aggregations.bucket.sampler.SamplerAggregator;
import org.elasticsearch.search.aggregations.bucket.sampler.SamplerAggregator.ExecutionMode;
import org.elasticsearch.search.aggregations.support.ValuesSourceType;
public class DiversifiedSamplerTests extends BaseAggregationTestCase<SamplerAggregator.DiversifiedFactory> {
@Override
protected final SamplerAggregator.DiversifiedFactory createTestAggregatorFactory() {
SamplerAggregator.DiversifiedFactory factory = new SamplerAggregator.DiversifiedFactory("foo", ValuesSourceType.ANY,
null);
String field = randomNumericField();
int randomFieldBranch = randomInt(3);
switch (randomFieldBranch) {
case 0:
factory.field(field);
break;
case 1:
factory.field(field);
factory.script(new Script("_value + 1"));
break;
case 2:
factory.script(new Script("doc[" + field + "] + 1"));
break;
}
if (randomBoolean()) {
factory.missing("MISSING");
}
if (randomBoolean()) {
factory.maxDocsPerValue(randomIntBetween(1, 1000));
}
if (randomBoolean()) {
factory.shardSize(randomIntBetween(1, 1000));
}
if (randomBoolean()) {
factory.executionHint(randomFrom(ExecutionMode.values()).toString());
}
return factory;
}
}

112
core/src/test/java/org/elasticsearch/search/aggregations/bucket/SamplerIT.java
View File

@ -123,7 +123,7 @@ public class SamplerIT extends ESIntegTestCase {
}
public void testNoDiversity() throws Exception {
public void testSimpleSampler() throws Exception {
SamplerAggregationBuilder sampleAgg = new SamplerAggregationBuilder("sample").shardSize(100);
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
SearchResponse response = client().prepareSearch("test").setSearchType(SearchType.QUERY_AND_FETCH)
@ -140,86 +140,6 @@ public class SamplerIT extends ESIntegTestCase {
assertThat(maxBooksPerAuthor, equalTo(3l));
}
public void testSimpleDiversity() throws Exception {
int MAX_DOCS_PER_AUTHOR = 1;
SamplerAggregationBuilder sampleAgg = new SamplerAggregationBuilder("sample").shardSize(100);
sampleAgg.field("author").maxDocsPerValue(MAX_DOCS_PER_AUTHOR).executionHint(randomExecutionHint());
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
SearchResponse response = client().prepareSearch("test")
.setSearchType(SearchType.QUERY_AND_FETCH)
.setQuery(new TermQueryBuilder("genre", "fantasy"))
.setFrom(0).setSize(60)
.addAggregation(sampleAgg)
.execute()
.actionGet();
assertSearchResponse(response);
Sampler sample = response.getAggregations().get("sample");
Terms authors = sample.getAggregations().get("authors");
Collection<Bucket> testBuckets = authors.getBuckets();
for (Terms.Bucket testBucket : testBuckets) {
assertThat(testBucket.getDocCount(), lessThanOrEqualTo((long) NUM_SHARDS * MAX_DOCS_PER_AUTHOR));
}
}
public void testNestedDiversity() throws Exception {
// Test multiple samples gathered under buckets made by a parent agg
int MAX_DOCS_PER_AUTHOR = 1;
TermsBuilder rootTerms = new TermsBuilder("genres").field("genre");
SamplerAggregationBuilder sampleAgg = new SamplerAggregationBuilder("sample").shardSize(100);
sampleAgg.field("author").maxDocsPerValue(MAX_DOCS_PER_AUTHOR).executionHint(randomExecutionHint());
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
rootTerms.subAggregation(sampleAgg);
SearchResponse response = client().prepareSearch("test").setSearchType(SearchType.QUERY_AND_FETCH)
.addAggregation(rootTerms).execute().actionGet();
assertSearchResponse(response);
Terms genres = response.getAggregations().get("genres");
Collection<Bucket> genreBuckets = genres.getBuckets();
for (Terms.Bucket genreBucket : genreBuckets) {
Sampler sample = genreBucket.getAggregations().get("sample");
Terms authors = sample.getAggregations().get("authors");
Collection<Bucket> testBuckets = authors.getBuckets();
for (Terms.Bucket testBucket : testBuckets) {
assertThat(testBucket.getDocCount(), lessThanOrEqualTo((long) NUM_SHARDS * MAX_DOCS_PER_AUTHOR));
}
}
}
public void testNestedSamples() throws Exception {
// Test samples nested under samples
int MAX_DOCS_PER_AUTHOR = 1;
int MAX_DOCS_PER_GENRE = 2;
SamplerAggregationBuilder rootSample = new SamplerAggregationBuilder("genreSample").shardSize(100).field("genre")
.maxDocsPerValue(MAX_DOCS_PER_GENRE);
SamplerAggregationBuilder sampleAgg = new SamplerAggregationBuilder("sample").shardSize(100);
sampleAgg.field("author").maxDocsPerValue(MAX_DOCS_PER_AUTHOR).executionHint(randomExecutionHint());
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
sampleAgg.subAggregation(new TermsBuilder("genres").field("genre"));
rootSample.subAggregation(sampleAgg);
SearchResponse response = client().prepareSearch("test").setSearchType(SearchType.QUERY_AND_FETCH).addAggregation(rootSample)
.execute().actionGet();
assertSearchResponse(response);
Sampler genreSample = response.getAggregations().get("genreSample");
Sampler sample = genreSample.getAggregations().get("sample");
Terms genres = sample.getAggregations().get("genres");
Collection<Bucket> testBuckets = genres.getBuckets();
for (Terms.Bucket testBucket : testBuckets) {
assertThat(testBucket.getDocCount(), lessThanOrEqualTo((long) NUM_SHARDS * MAX_DOCS_PER_GENRE));
}
Terms authors = sample.getAggregations().get("authors");
testBuckets = authors.getBuckets();
for (Terms.Bucket testBucket : testBuckets) {
assertThat(testBucket.getDocCount(), lessThanOrEqualTo((long) NUM_SHARDS * MAX_DOCS_PER_AUTHOR));
}
}
public void testUnmappedChildAggNoDiversity() throws Exception {
SamplerAggregationBuilder sampleAgg = new SamplerAggregationBuilder("sample").shardSize(100);
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
@ -254,34 +174,4 @@ public class SamplerIT extends ESIntegTestCase {
assertThat(authors.getBuckets().size(), greaterThan(0));
}
public void testPartiallyUnmappedDiversifyField() throws Exception {
// One of the indexes is missing the "author" field used for
// diversifying results
SamplerAggregationBuilder sampleAgg = new SamplerAggregationBuilder("sample").shardSize(100).field("author").maxDocsPerValue(1);
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
SearchResponse response = client().prepareSearch("idx_unmapped_author", "test").setSearchType(SearchType.QUERY_AND_FETCH)
.setQuery(new TermQueryBuilder("genre", "fantasy")).setFrom(0).setSize(60).addAggregation(sampleAgg)
.execute().actionGet();
assertSearchResponse(response);
Sampler sample = response.getAggregations().get("sample");
assertThat(sample.getDocCount(), greaterThan(0l));
Terms authors = sample.getAggregations().get("authors");
assertThat(authors.getBuckets().size(), greaterThan(0));
}
public void testWhollyUnmappedDiversifyField() throws Exception {
//All of the indices are missing the "author" field used for diversifying results
int MAX_DOCS_PER_AUTHOR = 1;
SamplerAggregationBuilder sampleAgg = new SamplerAggregationBuilder("sample").shardSize(100);
sampleAgg.field("author").maxDocsPerValue(MAX_DOCS_PER_AUTHOR).executionHint(randomExecutionHint());
sampleAgg.subAggregation(new TermsBuilder("authors").field("author"));
SearchResponse response = client().prepareSearch("idx_unmapped", "idx_unmapped_author").setSearchType(SearchType.QUERY_AND_FETCH)
.setQuery(new TermQueryBuilder("genre", "fantasy")).setFrom(0).setSize(60).addAggregation(sampleAgg).execute().actionGet();
assertSearchResponse(response);
Sampler sample = response.getAggregations().get("sample");
assertThat(sample.getDocCount(), equalTo(0l));
Terms authors = sample.getAggregations().get("authors");
assertNull(authors);
}
}

36
core/src/test/java/org/elasticsearch/search/aggregations/bucket/SamplerTests.java Normal file
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@ -0,0 +1,36 @@
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.search.aggregations.bucket;
import org.elasticsearch.search.aggregations.BaseAggregationTestCase;
import org.elasticsearch.search.aggregations.bucket.sampler.SamplerAggregator;
public class SamplerTests extends BaseAggregationTestCase<SamplerAggregator.Factory> {
@Override
protected final SamplerAggregator.Factory createTestAggregatorFactory() {
SamplerAggregator.Factory factory = new SamplerAggregator.Factory("foo");
if (randomBoolean()) {
factory.shardSize(randomIntBetween(1, 1000));
}
return factory;
}
}

2
docs/reference/aggregations/bucket.asciidoc
View File

@ -19,6 +19,8 @@ include::bucket/datehistogram-aggregation.asciidoc[]
include::bucket/daterange-aggregation.asciidoc[]
include::bucket/diversified-sampler-aggregation.asciidoc[]
include::bucket/filter-aggregation.asciidoc[]
include::bucket/filters-aggregation.asciidoc[]

154
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View File

@ -0,0 +1,154 @@
[[search-aggregations-bucket-sampler-aggregation]]
=== Sampler Aggregation
experimental[]
A filtering aggregation used to limit any sub aggregations' processing to a sample of the top-scoring documents. Diversity settings are
used to limit the number of matches that share a common value such as an "author".
.Example use cases:
* Tightening the focus of analytics to high-relevance matches rather than the potentially very long tail of low-quality matches
* Removing bias from analytics by ensuring fair representation of content from different sources
* Reducing the running cost of aggregations that can produce useful results using only samples e.g. `significant_terms`
Example:
[source,js]
--------------------------------------------------
{
"query": {
"match": {
"text": "iphone"
}
},
"aggs": {
"sample": {
"sampler": {
"shard_size": 200,
"field" : "user.id"
},
"aggs": {
"keywords": {
"significant_terms": {
"field": "text"
}
}
}
}
}
}
--------------------------------------------------
Response:
[source,js]
--------------------------------------------------
{
...
"aggregations": {
"sample": {
"doc_count": 1000,<1>
"keywords": {<2>
"doc_count": 1000,
"buckets": [
...
{
"key": "bend",
"doc_count": 58,
"score": 37.982536582524276,
"bg_count": 103
},
....
}
--------------------------------------------------
<1> 1000 documents were sampled in total becase we asked for a maximum of 200 from an index with 5 shards. The cost of performing the nested significant_terms aggregation was therefore limited rather than unbounded.
<2> The results of the significant_terms aggregation are not skewed by any single over-active Twitter user because we asked for a maximum of one tweet from any one user in our sample.
==== shard_size
The `shard_size` parameter limits how many top-scoring documents are collected in the sample processed on each shard.
The default value is 100.
==== Controlling diversity
=`field` or `script` and `max_docs_per_value` settings are used to control the maximum number of documents collected on any one shard which share a common value.
The choice of value (e.g. `author`) is loaded from a regular `field` or derived dynamically by a `script`.
The aggregation will throw an error if the choice of field or script produces multiple values for a document.
It is currently not possible to offer this form of de-duplication using many values, primarily due to concerns over efficiency.
NOTE: Any good market researcher will tell you that when working with samples of data it is important
that the sample represents a healthy variety of opinions rather than being skewed by any single voice.
The same is true with aggregations and sampling with these diversify settings can offer a way to remove the bias in your content (an over-populated geography, a large spike in a timeline or an over-active forum spammer).
==== Field
Controlling diversity using a field:
[source,js]
--------------------------------------------------
{
"aggs" : {
"sample" : {
"diverisfied_sampler" : {
"field" : "author",
"max_docs_per_value" : 3
}
}
}
}
--------------------------------------------------
Note that the `max_docs_per_value` setting applies on a per-shard basis only for the purposes of shard-local sampling.
It is not intended as a way of providing a global de-duplication feature on search results.
==== Script
Controlling diversity using a script:
[source,js]
--------------------------------------------------
{
"aggs" : {
"sample" : {
"diverisfied_sampler" : {
"script" : "doc['author'].value + '/' + doc['genre'].value"
}
}
}
}
--------------------------------------------------
Note in the above example we chose to use the default `max_docs_per_value` setting of 1 and combine author and genre fields to ensure
each shard sample has, at most, one match for an author/genre pair.
==== execution_hint
When using the settings to control diversity, the optional `execution_hint` setting can influence the management of the values used for de-duplication.
Each option will hold up to `shard_size` values in memory while performing de-duplication but the type of value held can be controlled as follows:
- hold field values directly (`map`)
- hold ordinals of the field as determined by the Lucene index (`global_ordinals`)
- hold hashes of the field values - with potential for hash collisions (`bytes_hash`)
The default setting is to use `global_ordinals` if this information is available from the Lucene index and reverting to `map` if not.
The `bytes_hash` setting may prove faster in some cases but introduces the possibility of false positives in de-duplication logic due to the possibility of hash collisions.
Please note that Elasticsearch will ignore the choice of execution hint if it is not applicable and that there is no backward compatibility guarantee on these hints.
==== Limitations
===== Cannot be nested under `breadth_first` aggregations
Being a quality-based filter the sampler aggregation needs access to the relevance score produced for each document.
It therefore cannot be nested under a `terms` aggregation which has the `collect_mode` switched from the default `depth_first` mode to `breadth_first` as this discards scores.
In this situation an error will be thrown.
===== Limited de-dup logic.
The de-duplication logic in the diversify settings applies only at a shard level so will not apply across shards.
===== No specialized syntax for geo/date fields
Currently the syntax for defining the diversifying values is defined by a choice of `field` or `script` - there is no added syntactical sugar for expressing geo or date units such as "1w" (1 week).
This support may be added in a later release and users will currently have to create these sorts of values using a script.

84
docs/reference/aggregations/bucket/sampler-aggregation.asciidoc
View File

@ -4,11 +4,9 @@
experimental[]
A filtering aggregation used to limit any sub aggregations' processing to a sample of the top-scoring documents.
Optionally, diversity settings can be used to limit the number of matches that share a common value such as an "author".
.Example use cases:
* Tightening the focus of analytics to high-relevance matches rather than the potentially very long tail of low-quality matches
* Removing bias from analytics by ensuring fair representation of content from different sources
* Reducing the running cost of aggregations that can produce useful results using only samples e.g. `significant_terms`
@ -25,8 +23,7 @@ Example:
"aggs": {
"sample": {
"sampler": {
"shard_size": 200,
"field" : "user.id"
"shard_size": 200
},
"aggs": {
"keywords": {
@ -63,8 +60,7 @@ Response:
}
--------------------------------------------------
<1> 1000 documents were sampled in total becase we asked for a maximum of 200 from an index with 5 shards. The cost of performing the nested significant_terms aggregation was therefore limited rather than unbounded.
<2> The results of the significant_terms aggregation are not skewed by any single over-active Twitter user because we asked for a maximum of one tweet from any one user in our sample.
<1> 1000 documents were sampled in total because we asked for a maximum of 200 from an index with 5 shards. The cost of performing the nested significant_terms aggregation was therefore limited rather than unbounded.
==== shard_size
@ -72,83 +68,9 @@ Response:
The `shard_size` parameter limits how many top-scoring documents are collected in the sample processed on each shard.
The default value is 100.
==== Controlling diversity
Optionally, you can use the `field` or `script` and `max_docs_per_value` settings to control the maximum number of documents collected on any one shard which share a common value.
The choice of value (e.g. `author`) is loaded from a regular `field` or derived dynamically by a `script`.
The aggregation will throw an error if the choice of field or script produces multiple values for a document.
It is currently not possible to offer this form of de-duplication using many values, primarily due to concerns over efficiency.
NOTE: Any good market researcher will tell you that when working with samples of data it is important
that the sample represents a healthy variety of opinions rather than being skewed by any single voice.
The same is true with aggregations and sampling with these diversify settings can offer a way to remove the bias in your content (an over-populated geography, a large spike in a timeline or an over-active forum spammer).
==== Field
Controlling diversity using a field:
[source,js]
--------------------------------------------------
{
"aggs" : {
"sample" : {
"sampler" : {
"field" : "author",
"max_docs_per_value" : 3
}
}
}
}
--------------------------------------------------
Note that the `max_docs_per_value` setting applies on a per-shard basis only for the purposes of shard-local sampling.
It is not intended as a way of providing a global de-duplication feature on search results.
==== Script
Controlling diversity using a script:
[source,js]
--------------------------------------------------
{
"aggs" : {
"sample" : {
"sampler" : {
"script" : "doc['author'].value + '/' + doc['genre'].value"
}
}
}
}
--------------------------------------------------
Note in the above example we chose to use the default `max_docs_per_value` setting of 1 and combine author and genre fields to ensure
each shard sample has, at most, one match for an author/genre pair.
==== execution_hint
When using the settings to control diversity, the optional `execution_hint` setting can influence the management of the values used for de-duplication.
Each option will hold up to `shard_size` values in memory while performing de-duplication but the type of value held can be controlled as follows:
- hold field values directly (`map`)
- hold ordinals of the field as determined by the Lucene index (`global_ordinals`)
- hold hashes of the field values - with potential for hash collisions (`bytes_hash`)
The default setting is to use `global_ordinals` if this information is available from the Lucene index and reverting to `map` if not.
The `bytes_hash` setting may prove faster in some cases but introduces the possibility of false positives in de-duplication logic due to the possibility of hash collisions.
Please note that Elasticsearch will ignore the choice of execution hint if it is not applicable and that there is no backward compatibility guarantee on these hints.
==== Limitations
===== Cannot be nested under `breadth_first` aggregations
Being a quality-based filter the sampler aggregation needs access to the relevance score produced for each document.
It therefore cannot be nested under a `terms` aggregation which has the `collect_mode` switched from the default `depth_first` mode to `breadth_first` as this discards scores.
In this situation an error will be thrown.
===== Limited de-dup logic.
The de-duplication logic in the diversify settings applies only at a shard level so will not apply across shards.
===== No specialized syntax for geo/date fields
Currently the syntax for defining the diversifying values is defined by a choice of `field` or `script` - there is no added syntactical sugar for expressing geo or date units such as "1w" (1 week).
This support may be added in a later release and users will currently have to create these sorts of values using a script.
In this situation an error will be thrown.