Removes parent child fielddata specialization (#24737)

This change removes the field data specialization needed for the parent field and replaces it with
a simple DocValuesIndexFieldData. The underlying global ordinals are retrieved via a new function called
IndexOrdinalsFieldData#getOrdinalMap.
The children aggregation is also modified to use a simple WithOrdinals value source rather than the deleted WithOrdinals.Parent.

Relates #20257

5 files changed, 63 insertions, 65 deletions

diff --git a/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ChildrenAggregationBuilder.java b/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ChildrenAggregationBuilder.java
index d04b1f0a66..35dc4eacbf 100644
--- a/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ChildrenAggregationBuilder.java
+++ b/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ChildrenAggregationBuilder.java
@@ -25,15 +25,16 @@ import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
-import org.elasticsearch.index.fielddata.plain.ParentChildIndexFieldData;
+import org.elasticsearch.index.fielddata.plain.SortedSetDVOrdinalsIndexFieldData;
 import org.elasticsearch.index.mapper.DocumentMapper;
+import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.ParentFieldMapper;
 import org.elasticsearch.index.query.QueryParseContext;
 import org.elasticsearch.search.aggregations.AggregatorFactories.Builder;
 import org.elasticsearch.search.aggregations.AggregatorFactory;
 import org.elasticsearch.search.aggregations.support.FieldContext;
 import org.elasticsearch.search.aggregations.support.ValueType;
-import org.elasticsearch.search.aggregations.support.ValuesSource.Bytes.ParentChild;
+import org.elasticsearch.search.aggregations.support.ValuesSource.Bytes.WithOrdinals;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregationBuilder;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
 import org.elasticsearch.search.aggregations.support.ValuesSourceConfig;
@@ -43,10 +44,11 @@ import org.elasticsearch.search.internal.SearchContext;
 import java.io.IOException;
 import java.util.Objects;
 
-public class ChildrenAggregationBuilder extends ValuesSourceAggregationBuilder<ParentChild, ChildrenAggregationBuilder> {
+public class ChildrenAggregationBuilder
+        extends ValuesSourceAggregationBuilder<WithOrdinals, ChildrenAggregationBuilder> {
+
     public static final String NAME = "children";
 
-    private String parentType;
     private final String childType;
     private Query parentFilter;
     private Query childFilter;
@@ -79,15 +81,17 @@ public class ChildrenAggregationBuilder extends ValuesSourceAggregationBuilder<P
     }
 
     @Override
-    protected ValuesSourceAggregatorFactory<ParentChild, ?> innerBuild(SearchContext context,
-            ValuesSourceConfig<ParentChild> config, AggregatorFactory<?> parent, Builder subFactoriesBuilder) throws IOException {
-        return new ChildrenAggregatorFactory(name, config, parentType, childFilter, parentFilter, context, parent,
+    protected ValuesSourceAggregatorFactory<WithOrdinals, ?> innerBuild(SearchContext context,
+                                                                        ValuesSourceConfig<WithOrdinals> config,
+                                                                        AggregatorFactory<?> parent,
+                                                                        Builder subFactoriesBuilder) throws IOException {
+        return new ChildrenAggregatorFactory(name, config, childFilter, parentFilter, context, parent,
                 subFactoriesBuilder, metaData);
     }
 
     @Override
-    protected ValuesSourceConfig<ParentChild> resolveConfig(SearchContext context) {
-        ValuesSourceConfig<ParentChild> config = new ValuesSourceConfig<>(ValuesSourceType.BYTES);
+    protected ValuesSourceConfig<WithOrdinals> resolveConfig(SearchContext context) {
+        ValuesSourceConfig<WithOrdinals> config = new ValuesSourceConfig<>(ValuesSourceType.BYTES);
         DocumentMapper childDocMapper = context.mapperService().documentMapper(childType);
 
         if (childDocMapper != null) {
@@ -95,15 +99,15 @@ public class ChildrenAggregationBuilder extends ValuesSourceAggregationBuilder<P
             if (!parentFieldMapper.active()) {
                 throw new IllegalArgumentException("[children] no [_parent] field not configured that points to a parent type");
             }
-            parentType = parentFieldMapper.type();
+            String parentType = parentFieldMapper.type();
             DocumentMapper parentDocMapper = context.mapperService().documentMapper(parentType);
             if (parentDocMapper != null) {
                 parentFilter = parentDocMapper.typeFilter(context.getQueryShardContext());
                 childFilter = childDocMapper.typeFilter(context.getQueryShardContext());
-                ParentChildIndexFieldData parentChildIndexFieldData = context.fieldData()
-                        .getForField(parentFieldMapper.fieldType());
-                config.fieldContext(new FieldContext(parentFieldMapper.fieldType().name(), parentChildIndexFieldData,
-                        parentFieldMapper.fieldType()));
+                MappedFieldType parentFieldType = parentDocMapper.parentFieldMapper().getParentJoinFieldType();
+                final SortedSetDVOrdinalsIndexFieldData fieldData = context.fieldData().getForField(parentFieldType);
+                config.fieldContext(new FieldContext(parentFieldType.name(), fieldData,
+                        parentFieldType));
             } else {
                 config.unmapped(true);
             }
@@ -145,7 +149,6 @@ public class ChildrenAggregationBuilder extends ValuesSourceAggregationBuilder<P
                     "Missing [child_type] field for children aggregation [" + aggregationName + "]");
         }
 
-
         return new ChildrenAggregationBuilder(aggregationName, childType);
     }
 
diff --git a/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ChildrenAggregatorFactory.java b/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ChildrenAggregatorFactory.java
index 800be74ba6..9c38fa2eae 100644
--- a/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ChildrenAggregatorFactory.java
+++ b/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ChildrenAggregatorFactory.java
@@ -26,8 +26,7 @@ import org.elasticsearch.search.aggregations.AggregatorFactory;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.NonCollectingAggregator;
 import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
-import org.elasticsearch.search.aggregations.support.ValuesSource;
-import org.elasticsearch.search.aggregations.support.ValuesSource.Bytes.ParentChild;
+import org.elasticsearch.search.aggregations.support.ValuesSource.Bytes.WithOrdinals;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
 import org.elasticsearch.search.aggregations.support.ValuesSourceConfig;
 import org.elasticsearch.search.internal.SearchContext;
@@ -37,17 +36,15 @@ import java.util.List;
 import java.util.Map;
 
 public class ChildrenAggregatorFactory
-        extends ValuesSourceAggregatorFactory<ValuesSource.Bytes.WithOrdinals.ParentChild, ChildrenAggregatorFactory> {
+        extends ValuesSourceAggregatorFactory<WithOrdinals, ChildrenAggregatorFactory> {
 
-    private final String parentType;
     private final Query parentFilter;
     private final Query childFilter;
 
-    public ChildrenAggregatorFactory(String name, ValuesSourceConfig<ParentChild> config, String parentType, Query childFilter,
-            Query parentFilter, SearchContext context, AggregatorFactory<?> parent, AggregatorFactories.Builder subFactoriesBuilder,
-            Map<String, Object> metaData) throws IOException {
+    public ChildrenAggregatorFactory(String name, ValuesSourceConfig<WithOrdinals> config,
+                                     Query childFilter, Query parentFilter, SearchContext context, AggregatorFactory<?> parent,
+                                     AggregatorFactories.Builder subFactoriesBuilder, Map<String, Object> metaData) throws IOException {
         super(name, config, context, parent, subFactoriesBuilder, metaData);
-        this.parentType = parentType;
         this.childFilter = childFilter;
         this.parentFilter = parentFilter;
     }
@@ -66,12 +63,11 @@ public class ChildrenAggregatorFactory
     }
 
     @Override
-    protected Aggregator doCreateInternal(ValuesSource.Bytes.WithOrdinals.ParentChild valuesSource, Aggregator parent,
+    protected Aggregator doCreateInternal(WithOrdinals valuesSource, Aggregator parent,
             boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
                     throws IOException {
-        long maxOrd = valuesSource.globalMaxOrd(context.searcher(), parentType);
-        return new ParentToChildrenAggregator(name, factories, context, parent, parentType, childFilter, parentFilter, valuesSource, maxOrd,
-                pipelineAggregators, metaData);
+        long maxOrd = valuesSource.globalMaxOrd(context.searcher());
+        return new ParentToChildrenAggregator(name, factories, context, parent, childFilter,
+            parentFilter, valuesSource, maxOrd, pipelineAggregators, metaData);
     }
-
 }
diff --git a/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ParentToChildrenAggregator.java b/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ParentToChildrenAggregator.java
index c1ffb097ab..93ba1b98da 100644
--- a/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ParentToChildrenAggregator.java
+++ b/modules/parent-join/src/main/java/org/elasticsearch/join/aggregations/ParentToChildrenAggregator.java
@@ -20,7 +20,7 @@ package org.elasticsearch.join.aggregations;
 
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.index.SortedDocValues;
+import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.search.ConstantScoreScorer;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.Query;
@@ -52,10 +52,9 @@ public class ParentToChildrenAggregator extends SingleBucketAggregator {
 
     static final ParseField TYPE_FIELD = new ParseField("type");
 
-    private final String parentType;
     private final Weight childFilter;
     private final Weight parentFilter;
-    private final ValuesSource.Bytes.WithOrdinals.ParentChild valuesSource;
+    private final ValuesSource.Bytes.WithOrdinals valuesSource;
 
     // Maybe use PagedGrowableWriter? This will be less wasteful than LongArray,
     // but then we don't have the reuse feature of BigArrays.
@@ -72,12 +71,11 @@ public class ParentToChildrenAggregator extends SingleBucketAggregator {
     private boolean multipleBucketsPerParentOrd = false;
 
     public ParentToChildrenAggregator(String name, AggregatorFactories factories,
-            SearchContext context, Aggregator parent, String parentType, Query childFilter,
-            Query parentFilter, ValuesSource.Bytes.WithOrdinals.ParentChild valuesSource,
+            SearchContext context, Aggregator parent, Query childFilter,
+            Query parentFilter, ValuesSource.Bytes.WithOrdinals valuesSource,
             long maxOrd, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
             throws IOException {
         super(name, factories, context, parent, pipelineAggregators, metaData);
-        this.parentType = parentType;
         // these two filters are cached in the parser
         this.childFilter = context.searcher().createNormalizedWeight(childFilter, false);
         this.parentFilter = context.searcher().createNormalizedWeight(parentFilter, false);
@@ -105,9 +103,7 @@ public class ParentToChildrenAggregator extends SingleBucketAggregator {
         if (valuesSource == null) {
             return LeafBucketCollector.NO_OP_COLLECTOR;
         }
-
-        final SortedDocValues globalOrdinals = valuesSource.globalOrdinalsValues(parentType, ctx);
-        assert globalOrdinals != null;
+        final SortedSetDocValues globalOrdinals = valuesSource.globalOrdinalsValues(ctx);
         Scorer parentScorer = parentFilter.scorer(ctx);
         final Bits parentDocs = Lucene.asSequentialAccessBits(ctx.reader().maxDoc(), parentScorer);
         return new LeafBucketCollector() {
@@ -115,7 +111,8 @@ public class ParentToChildrenAggregator extends SingleBucketAggregator {
             @Override
             public void collect(int docId, long bucket) throws IOException {
                 if (parentDocs.get(docId) && globalOrdinals.advanceExact(docId)) {
-                    long globalOrdinal = globalOrdinals.ordValue();
+                    long globalOrdinal = globalOrdinals.nextOrd();
+                    assert globalOrdinals.nextOrd() == SortedSetDocValues.NO_MORE_ORDS;
                     if (globalOrdinal != -1) {
                         if (parentOrdToBuckets.get(globalOrdinal) == -1) {
                             parentOrdToBuckets.set(globalOrdinal, bucket);
@@ -147,9 +144,8 @@ public class ParentToChildrenAggregator extends SingleBucketAggregator {
             DocIdSetIterator childDocsIter = childDocsScorer.iterator();
 
             final LeafBucketCollector sub = collectableSubAggregators.getLeafCollector(ctx);
-            final SortedDocValues globalOrdinals = valuesSource.globalOrdinalsValues(parentType,
-                    ctx);
 
+            final SortedSetDocValues globalOrdinals = valuesSource.globalOrdinalsValues(ctx);
             // Set the scorer, since we now replay only the child docIds
             sub.setScorer(new ConstantScoreScorer(null, 1f, childDocsIter));
 
@@ -161,7 +157,8 @@ public class ParentToChildrenAggregator extends SingleBucketAggregator {
                     continue;
                 }
                 if (globalOrdinals.advanceExact(docId)) {
-                    long globalOrdinal = globalOrdinals.ordValue();
+                    long globalOrdinal = globalOrdinals.nextOrd();
+                    assert globalOrdinals.nextOrd() == SortedSetDocValues.NO_MORE_ORDS;
                     long bucketOrd = parentOrdToBuckets.get(globalOrdinal);
                     if (bucketOrd != -1) {
                         collectBucket(sub, docId, bucketOrd);
diff --git a/modules/parent-join/src/main/java/org/elasticsearch/join/query/HasChildQueryBuilder.java b/modules/parent-join/src/main/java/org/elasticsearch/join/query/HasChildQueryBuilder.java
index 494c5e498e..95d000e3cc 100644
--- a/modules/parent-join/src/main/java/org/elasticsearch/join/query/HasChildQueryBuilder.java
+++ b/modules/parent-join/src/main/java/org/elasticsearch/join/query/HasChildQueryBuilder.java
@@ -34,9 +34,10 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.lucene.search.Queries;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
-import org.elasticsearch.index.fielddata.IndexParentChildFieldData;
-import org.elasticsearch.index.fielddata.plain.ParentChildIndexFieldData;
+import org.elasticsearch.index.fielddata.IndexOrdinalsFieldData;
+import org.elasticsearch.index.fielddata.plain.SortedSetDVOrdinalsIndexFieldData;
 import org.elasticsearch.index.mapper.DocumentMapper;
+import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.ParentFieldMapper;
 import org.elasticsearch.index.query.AbstractQueryBuilder;
 import org.elasticsearch.index.query.InnerHitBuilder;
@@ -48,7 +49,6 @@ import org.elasticsearch.index.query.QueryShardContext;
 import org.elasticsearch.index.query.QueryShardException;
 
 import java.io.IOException;
-import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 
@@ -324,9 +324,10 @@ public class HasChildQueryBuilder extends AbstractQueryBuilder<HasChildQueryBuil
         // wrap the query with type query
         innerQuery = Queries.filtered(innerQuery, childDocMapper.typeFilter(context));
 
-        final ParentChildIndexFieldData parentChildIndexFieldData = context.getForField(parentFieldMapper.fieldType());
+        final MappedFieldType parentFieldType = parentDocMapper.parentFieldMapper().getParentJoinFieldType();
+        final SortedSetDVOrdinalsIndexFieldData fieldData = context.getForField(parentFieldType);
         return new LateParsingQuery(parentDocMapper.typeFilter(context), innerQuery, minChildren(), maxChildren(),
-                                    parentType, scoreMode, parentChildIndexFieldData, context.getSearchSimilarity());
+            parentType, scoreMode, fieldData, context.getSearchSimilarity());
     }
 
     /**
@@ -347,19 +348,19 @@ public class HasChildQueryBuilder extends AbstractQueryBuilder<HasChildQueryBuil
         private final int maxChildren;
         private final String parentType;
         private final ScoreMode scoreMode;
-        private final ParentChildIndexFieldData parentChildIndexFieldData;
+        private final SortedSetDVOrdinalsIndexFieldData fieldDataJoin;
         private final Similarity similarity;
 
         LateParsingQuery(Query toQuery, Query innerQuery, int minChildren, int maxChildren,
-                         String parentType, ScoreMode scoreMode, ParentChildIndexFieldData parentChildIndexFieldData,
-                         Similarity similarity) {
+                         String parentType, ScoreMode scoreMode,
+                         SortedSetDVOrdinalsIndexFieldData fieldData, Similarity similarity) {
             this.toQuery = toQuery;
             this.innerQuery = innerQuery;
             this.minChildren = minChildren;
             this.maxChildren = maxChildren;
             this.parentType = parentType;
             this.scoreMode = scoreMode;
-            this.parentChildIndexFieldData = parentChildIndexFieldData;
+            this.fieldDataJoin = fieldData;
             this.similarity = similarity;
         }
 
@@ -374,10 +375,10 @@ public class HasChildQueryBuilder extends AbstractQueryBuilder<HasChildQueryBuil
                 IndexSearcher indexSearcher = new IndexSearcher(reader);
                 indexSearcher.setQueryCache(null);
                 indexSearcher.setSimilarity(similarity);
-                IndexParentChildFieldData indexParentChildFieldData = parentChildIndexFieldData.loadGlobal((DirectoryReader) reader);
-                MultiDocValues.OrdinalMap ordinalMap = ParentChildIndexFieldData.getOrdinalMap(indexParentChildFieldData, parentType);
+                IndexOrdinalsFieldData indexParentChildFieldData = fieldDataJoin.loadGlobal((DirectoryReader) reader);
+                MultiDocValues.OrdinalMap ordinalMap = indexParentChildFieldData.getOrdinalMap();
                 return JoinUtil.createJoinQuery(joinField, innerQuery, toQuery, indexSearcher, scoreMode,
-                        ordinalMap, minChildren, maxChildren);
+                    ordinalMap, minChildren, maxChildren);
             } else {
                 if (reader.leaves().isEmpty() && reader.numDocs() == 0) {
                     // asserting reader passes down a MultiReader during rewrite which makes this
@@ -387,7 +388,7 @@ public class HasChildQueryBuilder extends AbstractQueryBuilder<HasChildQueryBuil
                     return new MatchNoDocsQuery();
                 }
                 throw new IllegalStateException("can't load global ordinals for reader of type: " +
-                        reader.getClass() + " must be a DirectoryReader");
+                    reader.getClass() + " must be a DirectoryReader");
             }
         }
 
diff --git a/modules/parent-join/src/main/java/org/elasticsearch/join/query/HasParentQueryBuilder.java b/modules/parent-join/src/main/java/org/elasticsearch/join/query/HasParentQueryBuilder.java
index ca0bfd623d..b216e886a5 100644
--- a/modules/parent-join/src/main/java/org/elasticsearch/join/query/HasParentQueryBuilder.java
+++ b/modules/parent-join/src/main/java/org/elasticsearch/join/query/HasParentQueryBuilder.java
@@ -30,8 +30,9 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.lucene.search.Queries;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
-import org.elasticsearch.index.fielddata.plain.ParentChildIndexFieldData;
+import org.elasticsearch.index.fielddata.plain.SortedSetDVOrdinalsIndexFieldData;
 import org.elasticsearch.index.mapper.DocumentMapper;
+import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.ParentFieldMapper;
 import org.elasticsearch.index.query.AbstractQueryBuilder;
 import org.elasticsearch.index.query.InnerHitBuilder;
@@ -176,15 +177,12 @@ public class HasParentQueryBuilder extends AbstractQueryBuilder<HasParentQueryBu
         }
 
         Set<String> childTypes = new HashSet<>();
-        ParentChildIndexFieldData parentChildIndexFieldData = null;
         for (DocumentMapper documentMapper : context.getMapperService().docMappers(false)) {
             ParentFieldMapper parentFieldMapper = documentMapper.parentFieldMapper();
             if (parentFieldMapper.active() && type.equals(parentFieldMapper.type())) {
                 childTypes.add(documentMapper.type());
-                parentChildIndexFieldData = context.getForField(parentFieldMapper.fieldType());
             }
         }
-
         if (childTypes.isEmpty()) {
             throw new QueryShardException(context, "[" + NAME + "] no child types found for type [" + type + "]");
         }
@@ -204,14 +202,17 @@ public class HasParentQueryBuilder extends AbstractQueryBuilder<HasParentQueryBu
 
         // wrap the query with type query
         innerQuery = Queries.filtered(innerQuery, parentDocMapper.typeFilter(context));
+
+        final MappedFieldType parentType = parentDocMapper.parentFieldMapper().getParentJoinFieldType();
+        final SortedSetDVOrdinalsIndexFieldData fieldData = context.getForField(parentType);
         return new HasChildQueryBuilder.LateParsingQuery(childrenQuery,
-                                                         innerQuery,
-                                                         HasChildQueryBuilder.DEFAULT_MIN_CHILDREN,
-                                                         HasChildQueryBuilder.DEFAULT_MAX_CHILDREN,
-                                                         type,
-                                                         score ? ScoreMode.Max : ScoreMode.None,
-                                                         parentChildIndexFieldData,
-                                                         context.getSearchSimilarity());
+            innerQuery,
+            HasChildQueryBuilder.DEFAULT_MIN_CHILDREN,
+            HasChildQueryBuilder.DEFAULT_MAX_CHILDREN,
+            type,
+            score ? ScoreMode.Max : ScoreMode.None,
+            fieldData,
+            context.getSearchSimilarity());
     }
 
     @Override