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

14 files changed, 102 insertions, 766 deletions

diff --git a/core/src/main/java/org/elasticsearch/index/fielddata/AtomicParentChildFieldData.java b/core/src/main/java/org/elasticsearch/index/fielddata/AtomicParentChildFieldData.java
deleted file mode 100644
index f88d7c5877..0000000000
--- a/core/src/main/java/org/elasticsearch/index/fielddata/AtomicParentChildFieldData.java
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
- * 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.index.fielddata;
-
-import org.apache.lucene.index.SortedDocValues;
-
-import java.util.Set;
-
-/**
- * Specialization of {@link AtomicFieldData} for parent/child mappings.
- */
-public interface AtomicParentChildFieldData extends AtomicFieldData {
-
-    /**
-     * Return the set of types there is a mapping for.
-     */
-    Set<String> types();
-
-    /**
-     * Return the mapping for the given type. The returned
-     * {@link SortedDocValues} will map doc IDs to the identifier of their
-     * parent.
-     */
-    SortedDocValues getOrdinalsValues(String type);
-
-}
diff --git a/core/src/main/java/org/elasticsearch/index/fielddata/IndexOrdinalsFieldData.java b/core/src/main/java/org/elasticsearch/index/fielddata/IndexOrdinalsFieldData.java
index cb1471179c..2e714fc80a 100644
--- a/core/src/main/java/org/elasticsearch/index/fielddata/IndexOrdinalsFieldData.java
+++ b/core/src/main/java/org/elasticsearch/index/fielddata/IndexOrdinalsFieldData.java
@@ -21,7 +21,7 @@ package org.elasticsearch.index.fielddata;
 
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-
+import org.apache.lucene.index.MultiDocValues;
 
 
 /**
@@ -42,4 +42,9 @@ public interface IndexOrdinalsFieldData extends IndexFieldData.Global<AtomicOrdi
     @Override
     IndexOrdinalsFieldData localGlobalDirect(DirectoryReader indexReader) throws Exception;
 
+    /**
+     * Returns the underlying {@link MultiDocValues.OrdinalMap} for this fielddata
+     * or null if global ordinals are not needed (constant value or single segment).
+     */
+    MultiDocValues.OrdinalMap getOrdinalMap();
 }
diff --git a/core/src/main/java/org/elasticsearch/index/fielddata/IndexParentChildFieldData.java b/core/src/main/java/org/elasticsearch/index/fielddata/IndexParentChildFieldData.java
deleted file mode 100644
index 0453b3f1a1..0000000000
--- a/core/src/main/java/org/elasticsearch/index/fielddata/IndexParentChildFieldData.java
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * 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.index.fielddata;
-
-import org.apache.lucene.index.DirectoryReader;
-import org.apache.lucene.index.IndexReader;
-
-
-
-
-/**
- * Soecialization of {@link IndexFieldData} for parent/child mappings.
- */
-public interface IndexParentChildFieldData extends IndexFieldData.Global<AtomicParentChildFieldData> {
-
-    /**
-     * Load a global view of the ordinals for the given {@link IndexReader},
-     * potentially from a cache.
-     */
-    @Override
-    IndexParentChildFieldData loadGlobal(DirectoryReader indexReader);
-
-    /**
-     * Load a global view of the ordinals for the given {@link IndexReader}.
-     */
-    @Override
-    IndexParentChildFieldData localGlobalDirect(DirectoryReader indexReader) throws Exception;
-
-}
diff --git a/core/src/main/java/org/elasticsearch/index/fielddata/UidIndexFieldData.java b/core/src/main/java/org/elasticsearch/index/fielddata/UidIndexFieldData.java
index e8dea836e3..d0e8285be2 100644
--- a/core/src/main/java/org/elasticsearch/index/fielddata/UidIndexFieldData.java
+++ b/core/src/main/java/org/elasticsearch/index/fielddata/UidIndexFieldData.java
@@ -21,6 +21,7 @@ package org.elasticsearch.index.fielddata;
 
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.MultiDocValues;
 import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.util.BytesRef;
@@ -99,6 +100,11 @@ public final class UidIndexFieldData implements IndexOrdinalsFieldData {
         return new UidIndexFieldData(index, type, idFieldData.localGlobalDirect(indexReader));
     }
 
+    @Override
+    public MultiDocValues.OrdinalMap getOrdinalMap() {
+        return idFieldData.getOrdinalMap();
+    }
+
     static final class UidAtomicFieldData implements AtomicOrdinalsFieldData {
 
         private final BytesRef prefix;
diff --git a/core/src/main/java/org/elasticsearch/index/fielddata/ordinals/GlobalOrdinalsBuilder.java b/core/src/main/java/org/elasticsearch/index/fielddata/ordinals/GlobalOrdinalsBuilder.java
index 49140968ca..0a8ab3ccd4 100644
--- a/core/src/main/java/org/elasticsearch/index/fielddata/ordinals/GlobalOrdinalsBuilder.java
+++ b/core/src/main/java/org/elasticsearch/index/fielddata/ordinals/GlobalOrdinalsBuilder.java
@@ -74,7 +74,7 @@ public enum GlobalOrdinalsBuilder {
                     new TimeValue(System.nanoTime() - startTimeNS, TimeUnit.NANOSECONDS)
             );
         }
-        return new InternalGlobalOrdinalsIndexFieldData(indexSettings, indexFieldData.getFieldName(),
+        return new GlobalOrdinalsIndexFieldData(indexSettings, indexFieldData.getFieldName(),
                 atomicFD, ordinalMap, memorySizeInBytes, scriptFunction
         );
     }
@@ -108,7 +108,7 @@ public enum GlobalOrdinalsBuilder {
             subs[i] = atomicFD[i].getOrdinalsValues();
         }
         final OrdinalMap ordinalMap = OrdinalMap.build(null, subs, PackedInts.DEFAULT);
-        return new InternalGlobalOrdinalsIndexFieldData(indexSettings, indexFieldData.getFieldName(),
+        return new GlobalOrdinalsIndexFieldData(indexSettings, indexFieldData.getFieldName(),
                 atomicFD, ordinalMap, 0, AbstractAtomicOrdinalsFieldData.DEFAULT_SCRIPT_FUNCTION
         );
     }
diff --git a/core/src/main/java/org/elasticsearch/index/fielddata/ordinals/GlobalOrdinalsIndexFieldData.java b/core/src/main/java/org/elasticsearch/index/fielddata/ordinals/GlobalOrdinalsIndexFieldData.java
index 2055208021..795e4b9920 100644
--- a/core/src/main/java/org/elasticsearch/index/fielddata/ordinals/GlobalOrdinalsIndexFieldData.java
+++ b/core/src/main/java/org/elasticsearch/index/fielddata/ordinals/GlobalOrdinalsIndexFieldData.java
@@ -20,6 +20,8 @@ package org.elasticsearch.index.fielddata.ordinals;
 
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.MultiDocValues;
+import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.util.Accountable;
 import org.elasticsearch.common.Nullable;
@@ -29,23 +31,39 @@ import org.elasticsearch.index.fielddata.AtomicOrdinalsFieldData;
 import org.elasticsearch.index.fielddata.IndexFieldData;
 import org.elasticsearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.elasticsearch.index.fielddata.IndexOrdinalsFieldData;
+import org.elasticsearch.index.fielddata.ScriptDocValues;
+import org.elasticsearch.index.fielddata.plain.AbstractAtomicOrdinalsFieldData;
 import org.elasticsearch.search.MultiValueMode;
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.function.Function;
 
 /**
  * {@link IndexFieldData} base class for concrete global ordinals implementations.
  */
-public abstract class GlobalOrdinalsIndexFieldData extends AbstractIndexComponent implements IndexOrdinalsFieldData, Accountable {
+public class GlobalOrdinalsIndexFieldData extends AbstractIndexComponent implements IndexOrdinalsFieldData, Accountable {
 
     private final String fieldName;
     private final long memorySizeInBytes;
 
-    protected GlobalOrdinalsIndexFieldData(IndexSettings indexSettings, String fieldName, long memorySizeInBytes) {
+    private final MultiDocValues.OrdinalMap ordinalMap;
+    private final Atomic[] atomicReaders;
+    private final Function<SortedSetDocValues, ScriptDocValues<?>> scriptFunction;
+
+
+    protected GlobalOrdinalsIndexFieldData(IndexSettings indexSettings, String fieldName, AtomicOrdinalsFieldData[] segmentAfd,
+                                           MultiDocValues.OrdinalMap ordinalMap, long memorySizeInBytes, Function<SortedSetDocValues,
+                                           ScriptDocValues<?>> scriptFunction) {
         super(indexSettings);
         this.fieldName = fieldName;
         this.memorySizeInBytes = memorySizeInBytes;
+        this.ordinalMap = ordinalMap;
+        this.atomicReaders = new Atomic[segmentAfd.length];
+        for (int i = 0; i < segmentAfd.length; i++) {
+            atomicReaders[i] = new Atomic(segmentAfd[i], ordinalMap, i);
+        }
+        this.scriptFunction = scriptFunction;
     }
 
     @Override
@@ -88,4 +106,57 @@ public abstract class GlobalOrdinalsIndexFieldData extends AbstractIndexComponen
         // TODO: break down ram usage?
         return Collections.emptyList();
     }
+
+    @Override
+    public AtomicOrdinalsFieldData load(LeafReaderContext context) {
+        return atomicReaders[context.ord];
+    }
+
+    @Override
+    public MultiDocValues.OrdinalMap getOrdinalMap() {
+        return ordinalMap;
+    }
+
+    private final class Atomic extends AbstractAtomicOrdinalsFieldData {
+
+        private final AtomicOrdinalsFieldData afd;
+        private final MultiDocValues.OrdinalMap ordinalMap;
+        private final int segmentIndex;
+
+        private Atomic(AtomicOrdinalsFieldData afd, MultiDocValues.OrdinalMap ordinalMap, int segmentIndex) {
+            super(scriptFunction);
+            this.afd = afd;
+            this.ordinalMap = ordinalMap;
+            this.segmentIndex = segmentIndex;
+        }
+
+        @Override
+        public SortedSetDocValues getOrdinalsValues() {
+            final SortedSetDocValues values = afd.getOrdinalsValues();
+            if (values.getValueCount() == ordinalMap.getValueCount()) {
+                // segment ordinals match global ordinals
+                return values;
+            }
+            final SortedSetDocValues[] bytesValues = new SortedSetDocValues[atomicReaders.length];
+            for (int i = 0; i < bytesValues.length; i++) {
+                bytesValues[i] = atomicReaders[i].afd.getOrdinalsValues();
+            }
+            return new GlobalOrdinalMapping(ordinalMap, bytesValues, segmentIndex);
+        }
+
+        @Override
+        public long ramBytesUsed() {
+            return afd.ramBytesUsed();
+        }
+
+        @Override
+        public Collection<Accountable> getChildResources() {
+            return afd.getChildResources();
+        }
+
+        @Override
+        public void close() {
+        }
+
+    }
 }
diff --git a/core/src/main/java/org/elasticsearch/index/fielddata/ordinals/InternalGlobalOrdinalsIndexFieldData.java b/core/src/main/java/org/elasticsearch/index/fielddata/ordinals/InternalGlobalOrdinalsIndexFieldData.java
deleted file mode 100644
index 23ecc06fed..0000000000
--- a/core/src/main/java/org/elasticsearch/index/fielddata/ordinals/InternalGlobalOrdinalsIndexFieldData.java
+++ /dev/null
@@ -1,99 +0,0 @@
-/*
- * 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.index.fielddata.ordinals;
-
-import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.index.MultiDocValues.OrdinalMap;
-import org.apache.lucene.index.SortedSetDocValues;
-import org.apache.lucene.util.Accountable;
-import org.elasticsearch.index.IndexSettings;
-import org.elasticsearch.index.fielddata.AtomicOrdinalsFieldData;
-import org.elasticsearch.index.fielddata.ScriptDocValues;
-import org.elasticsearch.index.fielddata.plain.AbstractAtomicOrdinalsFieldData;
-
-import java.util.Collection;
-import java.util.function.Function;
-
-/**
- * {@link org.elasticsearch.index.fielddata.IndexFieldData} impl based on global ordinals.
- */
-final class InternalGlobalOrdinalsIndexFieldData extends GlobalOrdinalsIndexFieldData {
-
-    private final Atomic[] atomicReaders;
-    private final Function<SortedSetDocValues, ScriptDocValues<?>> scriptFunction;
-
-    InternalGlobalOrdinalsIndexFieldData(IndexSettings indexSettings, String fieldName, AtomicOrdinalsFieldData[] segmentAfd,
-            OrdinalMap ordinalMap, long memorySizeInBytes, Function<SortedSetDocValues, ScriptDocValues<?>> scriptFunction) {
-        super(indexSettings, fieldName, memorySizeInBytes);
-        this.atomicReaders = new Atomic[segmentAfd.length];
-        for (int i = 0; i < segmentAfd.length; i++) {
-            atomicReaders[i] = new Atomic(segmentAfd[i], ordinalMap, i);
-        }
-        this.scriptFunction = scriptFunction;
-    }
-
-    @Override
-    public AtomicOrdinalsFieldData load(LeafReaderContext context) {
-        return atomicReaders[context.ord];
-    }
-
-    private final class Atomic extends AbstractAtomicOrdinalsFieldData {
-
-        private final AtomicOrdinalsFieldData afd;
-        private final OrdinalMap ordinalMap;
-        private final int segmentIndex;
-
-        private Atomic(AtomicOrdinalsFieldData afd, OrdinalMap ordinalMap, int segmentIndex) {
-            super(scriptFunction);
-            this.afd = afd;
-            this.ordinalMap = ordinalMap;
-            this.segmentIndex = segmentIndex;
-        }
-
-        @Override
-        public SortedSetDocValues getOrdinalsValues() {
-            final SortedSetDocValues values = afd.getOrdinalsValues();
-            if (values.getValueCount() == ordinalMap.getValueCount()) {
-                // segment ordinals match global ordinals
-                return values;
-            }
-            final SortedSetDocValues[] bytesValues = new SortedSetDocValues[atomicReaders.length];
-            for (int i = 0; i < bytesValues.length; i++) {
-                bytesValues[i] = atomicReaders[i].afd.getOrdinalsValues();
-            }
-            return new GlobalOrdinalMapping(ordinalMap, bytesValues, segmentIndex);
-        }
-
-        @Override
-        public long ramBytesUsed() {
-            return afd.ramBytesUsed();
-        }
-
-        @Override
-        public Collection<Accountable> getChildResources() {
-            return afd.getChildResources();
-        }
-
-        @Override
-        public void close() {
-        }
-
-    }
-
-}
diff --git a/core/src/main/java/org/elasticsearch/index/fielddata/plain/AbstractAtomicParentChildFieldData.java b/core/src/main/java/org/elasticsearch/index/fielddata/plain/AbstractAtomicParentChildFieldData.java
deleted file mode 100644
index 2df5aa6bb6..0000000000
--- a/core/src/main/java/org/elasticsearch/index/fielddata/plain/AbstractAtomicParentChildFieldData.java
+++ /dev/null
@@ -1,128 +0,0 @@
-/*
- * 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.index.fielddata.plain;
-
-import org.apache.lucene.index.DocValues;
-import org.apache.lucene.index.SortedDocValues;
-import org.apache.lucene.util.Accountable;
-import org.apache.lucene.util.ArrayUtil;
-import org.apache.lucene.util.BytesRef;
-import org.elasticsearch.index.fielddata.AtomicParentChildFieldData;
-import org.elasticsearch.index.fielddata.ScriptDocValues;
-import org.elasticsearch.index.fielddata.SortedBinaryDocValues;
-
-import java.io.IOException;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Set;
-
-import static java.util.Collections.emptySet;
-
-
-abstract class AbstractAtomicParentChildFieldData implements AtomicParentChildFieldData {
-
-    @Override
-    public final ScriptDocValues getScriptValues() {
-        return new ScriptDocValues.Strings(getBytesValues());
-    }
-
-    @Override
-    public final SortedBinaryDocValues getBytesValues() {
-        return new SortedBinaryDocValues() {
-
-            private final SortedDocValues[] perTypeValues;
-            private final BytesRef[] terms = new BytesRef[2];
-            private int count;
-            private int termsCursor;
-
-            {
-                Set<String> types = types();
-                perTypeValues = new SortedDocValues[types.size()];
-                int i = 0;
-                for (String type : types) {
-                    perTypeValues[i++] = getOrdinalsValues(type);
-                }
-            }
-
-            @Override
-            public boolean advanceExact(int docId) throws IOException {
-                count = 0;
-                termsCursor = 0;
-
-                for (SortedDocValues values : perTypeValues) {
-                    if (values.advanceExact(docId)) {
-                        final int ord = values.ordValue();
-                        terms[count++] = values.lookupOrd(ord);
-                    }
-                }
-                assert count <= 2 : "A single doc can potentially be both parent and child, so the maximum allowed values is 2";
-                if (count > 1) {
-                    int cmp = terms[0].compareTo(terms[1]);
-                    if (cmp > 0) {
-                        ArrayUtil.swap(terms, 0, 1);
-                    } else if (cmp == 0) {
-                        // If the id is the same between types the only omit one. For example: a doc has parent#1 in _uid field and has grand_parent#1 in _parent field.
-                        count = 1;
-                    }
-                }
-                return count != 0;
-            }
-
-            @Override
-            public int docValueCount() {
-                return count;
-            }
-
-            @Override
-            public BytesRef nextValue() throws IOException {
-                return terms[termsCursor++];
-            }
-        };
-    }
-
-    public static AtomicParentChildFieldData empty() {
-        return new AbstractAtomicParentChildFieldData() {
-
-            @Override
-            public long ramBytesUsed() {
-                return 0;
-            }
-
-            @Override
-            public Collection<Accountable> getChildResources() {
-                return Collections.emptyList();
-            }
-
-            @Override
-            public void close() {
-            }
-
-            @Override
-            public SortedDocValues getOrdinalsValues(String type) {
-                return DocValues.emptySorted();
-            }
-
-            @Override
-            public Set<String> types() {
-                return emptySet();
-            }
-        };
-    }
-}
diff --git a/core/src/main/java/org/elasticsearch/index/fielddata/plain/AbstractIndexOrdinalsFieldData.java b/core/src/main/java/org/elasticsearch/index/fielddata/plain/AbstractIndexOrdinalsFieldData.java
index ce05e226b7..1dbd082f93 100644
--- a/core/src/main/java/org/elasticsearch/index/fielddata/plain/AbstractIndexOrdinalsFieldData.java
+++ b/core/src/main/java/org/elasticsearch/index/fielddata/plain/AbstractIndexOrdinalsFieldData.java
@@ -22,6 +22,7 @@ import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.FilteredTermsEnum;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.MultiDocValues;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.util.BytesRef;
@@ -52,6 +53,11 @@ public abstract class AbstractIndexOrdinalsFieldData extends AbstractIndexFieldD
     }
 
     @Override
+    public MultiDocValues.OrdinalMap getOrdinalMap() {
+        return null;
+    }
+
+    @Override
     public IndexOrdinalsFieldData loadGlobal(DirectoryReader indexReader) {
         if (indexReader.leaves().size() <= 1) {
             // ordinals are already global
diff --git a/core/src/main/java/org/elasticsearch/index/fielddata/plain/ParentChildIndexFieldData.java b/core/src/main/java/org/elasticsearch/index/fielddata/plain/ParentChildIndexFieldData.java
deleted file mode 100644
index 74b180f2c1..0000000000
--- a/core/src/main/java/org/elasticsearch/index/fielddata/plain/ParentChildIndexFieldData.java
+++ /dev/null
@@ -1,401 +0,0 @@
-/*
- * 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.index.fielddata.plain;
-
-import org.apache.lucene.index.DirectoryReader;
-import org.apache.lucene.index.DocValues;
-import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.index.LeafReader;
-import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.index.MultiDocValues;
-import org.apache.lucene.index.MultiDocValues.OrdinalMap;
-import org.apache.lucene.index.SortedDocValues;
-import org.apache.lucene.search.SortField;
-import org.apache.lucene.util.Accountable;
-import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.LongValues;
-import org.apache.lucene.util.packed.PackedInts;
-import org.elasticsearch.ElasticsearchException;
-import org.elasticsearch.common.Nullable;
-import org.elasticsearch.common.breaker.CircuitBreaker;
-import org.elasticsearch.common.lease.Releasable;
-import org.elasticsearch.common.lease.Releasables;
-import org.elasticsearch.common.unit.TimeValue;
-import org.elasticsearch.index.Index;
-import org.elasticsearch.index.IndexSettings;
-import org.elasticsearch.index.fielddata.AbstractSortedDocValues;
-import org.elasticsearch.index.fielddata.AtomicParentChildFieldData;
-import org.elasticsearch.index.fielddata.IndexFieldData;
-import org.elasticsearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
-import org.elasticsearch.index.fielddata.IndexFieldDataCache;
-import org.elasticsearch.index.fielddata.IndexParentChildFieldData;
-import org.elasticsearch.index.fielddata.fieldcomparator.BytesRefFieldComparatorSource;
-import org.elasticsearch.index.mapper.DocumentMapper;
-import org.elasticsearch.index.mapper.MappedFieldType;
-import org.elasticsearch.index.mapper.MapperService;
-import org.elasticsearch.index.mapper.ParentFieldMapper;
-import org.elasticsearch.indices.breaker.CircuitBreakerService;
-import org.elasticsearch.search.MultiValueMode;
-
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.concurrent.TimeUnit;
-
-/**
- * ParentChildIndexFieldData is responsible for loading the id cache mapping
- * needed for has_child and has_parent queries into memory.
- */
-public class ParentChildIndexFieldData extends AbstractIndexFieldData<AtomicParentChildFieldData> implements IndexParentChildFieldData {
-
-    private final Set<String> parentTypes;
-    private final CircuitBreakerService breakerService;
-
-    public ParentChildIndexFieldData(IndexSettings indexSettings, String fieldName,
-                                     IndexFieldDataCache cache, MapperService mapperService,
-                                     CircuitBreakerService breakerService) {
-        super(indexSettings, fieldName, cache);
-        this.breakerService = breakerService;
-        Set<String> parentTypes = new HashSet<>();
-        for (DocumentMapper mapper : mapperService.docMappers(false)) {
-            ParentFieldMapper parentFieldMapper = mapper.parentFieldMapper();
-            if (parentFieldMapper.active()) {
-                parentTypes.add(parentFieldMapper.type());
-            }
-        }
-        this.parentTypes = parentTypes;
-    }
-
-    @Override
-    public SortField sortField(@Nullable Object missingValue, MultiValueMode sortMode, Nested nested, boolean reverse) {
-        final XFieldComparatorSource source = new BytesRefFieldComparatorSource(this, missingValue, sortMode, nested);
-        return new SortField(getFieldName(), source, reverse);
-    }
-
-    @Override
-    public AtomicParentChildFieldData load(LeafReaderContext context) {
-        final LeafReader reader = context.reader();
-        return new AbstractAtomicParentChildFieldData() {
-
-            public Set<String> types() {
-                return parentTypes;
-            }
-
-            @Override
-            public SortedDocValues getOrdinalsValues(String type) {
-                try {
-                    return DocValues.getSorted(reader, ParentFieldMapper.joinField(type));
-                } catch (IOException e) {
-                    throw new IllegalStateException("cannot load join doc values field for type [" + type + "]", e);
-                }
-            }
-
-            @Override
-            public long ramBytesUsed() {
-                // unknown
-                return 0;
-            }
-
-            @Override
-            public Collection<Accountable> getChildResources() {
-                return Collections.emptyList();
-            }
-
-            @Override
-            public void close() throws ElasticsearchException {
-            }
-        };
-    }
-
-    @Override
-    public AbstractAtomicParentChildFieldData loadDirect(LeafReaderContext context) throws Exception {
-        throw new UnsupportedOperationException();
-    }
-
-    @Override
-    protected AtomicParentChildFieldData empty(int maxDoc) {
-        return AbstractAtomicParentChildFieldData.empty();
-    }
-
-    public static class Builder implements IndexFieldData.Builder {
-
-        @Override
-        public IndexFieldData<?> build(IndexSettings indexSettings,
-                                       MappedFieldType fieldType,
-                                       IndexFieldDataCache cache, CircuitBreakerService breakerService,
-                                       MapperService mapperService) {
-            return new ParentChildIndexFieldData(indexSettings, fieldType.name(), cache,
-                    mapperService, breakerService);
-        }
-    }
-
-    @Override
-    public IndexParentChildFieldData loadGlobal(DirectoryReader indexReader) {
-        if (indexReader.leaves().size() <= 1) {
-            // ordinals are already global
-            return this;
-        }
-        try {
-            return cache.load(indexReader, this);
-        } catch (Exception e) {
-            if (e instanceof ElasticsearchException) {
-                throw (ElasticsearchException) e;
-            } else {
-                throw new ElasticsearchException(e);
-            }
-        }
-    }
-
-    private static OrdinalMap buildOrdinalMap(AtomicParentChildFieldData[] atomicFD, String parentType) throws IOException {
-        final SortedDocValues[] ordinals = new SortedDocValues[atomicFD.length];
-        for (int i = 0; i < ordinals.length; ++i) {
-            ordinals[i] = atomicFD[i].getOrdinalsValues(parentType);
-        }
-        return OrdinalMap.build(null, ordinals, PackedInts.DEFAULT);
-    }
-
-    private static class OrdinalMapAndAtomicFieldData {
-        final OrdinalMap ordMap;
-        final AtomicParentChildFieldData[] fieldData;
-
-        OrdinalMapAndAtomicFieldData(OrdinalMap ordMap, AtomicParentChildFieldData[] fieldData) {
-            this.ordMap = ordMap;
-            this.fieldData = fieldData;
-        }
-    }
-
-    @Override
-    public IndexParentChildFieldData localGlobalDirect(DirectoryReader indexReader) throws Exception {
-        final long startTime = System.nanoTime();
-
-        long ramBytesUsed = 0;
-        final Map<String, OrdinalMapAndAtomicFieldData> perType = new HashMap<>();
-        for (String type : parentTypes) {
-            final AtomicParentChildFieldData[] fieldData = new AtomicParentChildFieldData[indexReader.leaves().size()];
-            for (LeafReaderContext context : indexReader.leaves()) {
-                fieldData[context.ord] = load(context);
-            }
-            final OrdinalMap ordMap = buildOrdinalMap(fieldData, type);
-            ramBytesUsed += ordMap.ramBytesUsed();
-            perType.put(type, new OrdinalMapAndAtomicFieldData(ordMap, fieldData));
-        }
-
-        final AtomicParentChildFieldData[] fielddata = new AtomicParentChildFieldData[indexReader.leaves().size()];
-        for (int i = 0; i < fielddata.length; ++i) {
-            fielddata[i] = new GlobalAtomicFieldData(parentTypes, perType, i);
-        }
-
-        breakerService.getBreaker(CircuitBreaker.FIELDDATA).addWithoutBreaking(ramBytesUsed);
-        if (logger.isDebugEnabled()) {
-            logger.debug(
-                    "global-ordinals [_parent] took [{}]",
-                    new TimeValue(System.nanoTime() - startTime, TimeUnit.NANOSECONDS)
-            );
-        }
-
-        return new GlobalFieldData(indexReader, fielddata, ramBytesUsed, perType);
-    }
-
-    private static class GlobalAtomicFieldData extends AbstractAtomicParentChildFieldData {
-
-        private final Set<String> types;
-        private final Map<String, OrdinalMapAndAtomicFieldData> atomicFD;
-        private final int segmentIndex;
-
-        GlobalAtomicFieldData(Set<String> types, Map<String, OrdinalMapAndAtomicFieldData> atomicFD, int segmentIndex) {
-            this.types = types;
-            this.atomicFD = atomicFD;
-            this.segmentIndex = segmentIndex;
-        }
-
-        @Override
-        public Set<String> types() {
-            return types;
-        }
-
-        @Override
-        public SortedDocValues getOrdinalsValues(String type) {
-            final OrdinalMapAndAtomicFieldData atomicFD = this.atomicFD.get(type);
-            if (atomicFD == null) {
-                return DocValues.emptySorted();
-            }
-
-            final OrdinalMap ordMap = atomicFD.ordMap;
-            final SortedDocValues[] allSegmentValues = new SortedDocValues[atomicFD.fieldData.length];
-            for (int i = 0; i < allSegmentValues.length; ++i) {
-                allSegmentValues[i] = atomicFD.fieldData[i].getOrdinalsValues(type);
-            }
-            final SortedDocValues segmentValues = allSegmentValues[segmentIndex];
-            if (segmentValues.getValueCount() == ordMap.getValueCount()) {
-                // ords are already global
-                return segmentValues;
-            }
-            final LongValues globalOrds = ordMap.getGlobalOrds(segmentIndex);
-            return new AbstractSortedDocValues() {
-
-                @Override
-                public BytesRef lookupOrd(int ord) throws IOException {
-                    final int segmentIndex = ordMap.getFirstSegmentNumber(ord);
-                    final int segmentOrd = (int) ordMap.getFirstSegmentOrd(ord);
-                    return allSegmentValues[segmentIndex].lookupOrd(segmentOrd);
-                }
-
-                @Override
-                public int getValueCount() {
-                    return (int) ordMap.getValueCount();
-                }
-
-                @Override
-                public int ordValue() throws IOException {
-                    return (int) globalOrds.get(segmentValues.ordValue());
-                }
-
-                @Override
-                public boolean advanceExact(int target) throws IOException {
-                    return segmentValues.advanceExact(target);
-                }
-
-                @Override
-                public int docID() {
-                    return segmentValues.docID();
-                }
-            };
-        }
-
-        @Override
-        public long ramBytesUsed() {
-            // this class does not take memory on its own, the index-level field data does
-            // it through the use of ordinal maps
-            return 0;
-        }
-
-        @Override
-        public Collection<Accountable> getChildResources() {
-            return Collections.emptyList();
-        }
-
-        @Override
-        public void close() {
-            List<Releasable> closeables = new ArrayList<>();
-            for (OrdinalMapAndAtomicFieldData fds : atomicFD.values()) {
-                closeables.addAll(Arrays.asList(fds.fieldData));
-            }
-            Releasables.close(closeables);
-        }
-
-    }
-
-    public class GlobalFieldData implements IndexParentChildFieldData, Accountable {
-
-        private final Object coreCacheKey;
-        private final List<LeafReaderContext> leaves;
-        private final AtomicParentChildFieldData[] fielddata;
-        private final long ramBytesUsed;
-        private final Map<String, OrdinalMapAndAtomicFieldData> ordinalMapPerType;
-
-        GlobalFieldData(IndexReader reader, AtomicParentChildFieldData[] fielddata, long ramBytesUsed, Map<String, OrdinalMapAndAtomicFieldData> ordinalMapPerType) {
-            this.coreCacheKey = reader.getReaderCacheHelper().getKey();
-            this.leaves = reader.leaves();
-            this.ramBytesUsed = ramBytesUsed;
-            this.fielddata = fielddata;
-            this.ordinalMapPerType = ordinalMapPerType;
-        }
-
-        @Override
-        public String getFieldName() {
-            return ParentChildIndexFieldData.this.getFieldName();
-        }
-
-        @Override
-        public AtomicParentChildFieldData load(LeafReaderContext context) {
-            assert context.reader().getCoreCacheHelper().getKey() == leaves.get(context.ord)
-                    .reader().getCoreCacheHelper().getKey();
-            return fielddata[context.ord];
-        }
-
-        @Override
-        public AtomicParentChildFieldData loadDirect(LeafReaderContext context) throws Exception {
-            return load(context);
-        }
-
-        @Override
-        public SortField sortField(@Nullable Object missingValue, MultiValueMode sortMode, Nested nested, boolean reverse) {
-            throw new UnsupportedOperationException("No sorting on global ords");
-        }
-
-        @Override
-        public void clear() {
-            ParentChildIndexFieldData.this.clear();
-        }
-
-        @Override
-        public Index index() {
-            return ParentChildIndexFieldData.this.index();
-        }
-
-        @Override
-        public long ramBytesUsed() {
-            return ramBytesUsed;
-        }
-
-        @Override
-        public Collection<Accountable> getChildResources() {
-            return Collections.emptyList();
-        }
-
-        @Override
-        public IndexParentChildFieldData loadGlobal(DirectoryReader indexReader) {
-            if (indexReader.getReaderCacheHelper().getKey() == coreCacheKey) {
-                return this;
-            }
-            throw new IllegalStateException();
-        }
-
-        @Override
-        public IndexParentChildFieldData localGlobalDirect(DirectoryReader indexReader) throws Exception {
-            return loadGlobal(indexReader);
-        }
-
-    }
-
-    /**
-     * Returns the global ordinal map for the specified type
-     */
-    // TODO: OrdinalMap isn't expose in the field data framework, because it is an implementation detail.
-    // However the JoinUtil works directly with OrdinalMap, so this is a hack to get access to OrdinalMap
-    // I don't think we should expose OrdinalMap in IndexFieldData, because only parent/child relies on it and for the
-    // rest of the code OrdinalMap is an implementation detail, but maybe we can expose it in IndexParentChildFieldData interface?
-    public static MultiDocValues.OrdinalMap getOrdinalMap(IndexParentChildFieldData indexParentChildFieldData, String type) {
-        if (indexParentChildFieldData instanceof ParentChildIndexFieldData.GlobalFieldData) {
-            return ((GlobalFieldData) indexParentChildFieldData).ordinalMapPerType.get(type).ordMap;
-        } else {
-            // one segment, local ordinals are global
-            return null;
-        }
-    }
-
-}
diff --git a/core/src/main/java/org/elasticsearch/index/fielddata/plain/SortedSetDVOrdinalsIndexFieldData.java b/core/src/main/java/org/elasticsearch/index/fielddata/plain/SortedSetDVOrdinalsIndexFieldData.java
index ea076d476d..9e6e2e994c 100644
--- a/core/src/main/java/org/elasticsearch/index/fielddata/plain/SortedSetDVOrdinalsIndexFieldData.java
+++ b/core/src/main/java/org/elasticsearch/index/fielddata/plain/SortedSetDVOrdinalsIndexFieldData.java
@@ -21,6 +21,7 @@ package org.elasticsearch.index.fielddata.plain;
 
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.MultiDocValues;
 import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.SortedSetSelector;
@@ -125,4 +126,9 @@ public class SortedSetDVOrdinalsIndexFieldData extends DocValuesIndexFieldData i
     public IndexOrdinalsFieldData localGlobalDirect(DirectoryReader indexReader) throws Exception {
         return GlobalOrdinalsBuilder.build(indexReader, this, indexSettings, breakerService, logger, scriptFunction);
     }
+
+    @Override
+    public MultiDocValues.OrdinalMap getOrdinalMap() {
+        return null;
+    }
 }
diff --git a/core/src/main/java/org/elasticsearch/index/mapper/ParentFieldMapper.java b/core/src/main/java/org/elasticsearch/index/mapper/ParentFieldMapper.java
index 62877567c3..3ef9b73708 100644
--- a/core/src/main/java/org/elasticsearch/index/mapper/ParentFieldMapper.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/ParentFieldMapper.java
@@ -37,7 +37,7 @@ import org.elasticsearch.common.settings.loader.SettingsLoader;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
 import org.elasticsearch.index.fielddata.IndexFieldData;
-import org.elasticsearch.index.fielddata.plain.ParentChildIndexFieldData;
+import org.elasticsearch.index.fielddata.plain.DocValuesIndexFieldData;
 import org.elasticsearch.index.query.QueryShardContext;
 
 import java.io.IOException;
@@ -196,7 +196,7 @@ public class ParentFieldMapper extends MetadataFieldMapper {
 
         @Override
         public IndexFieldData.Builder fielddataBuilder() {
-            return new ParentChildIndexFieldData.Builder();
+            return new DocValuesIndexFieldData.Builder();
         }
     }
 
diff --git a/core/src/main/java/org/elasticsearch/search/aggregations/support/ValuesSource.java b/core/src/main/java/org/elasticsearch/search/aggregations/support/ValuesSource.java
index e6ed81c2d8..a8aaa25940 100644
--- a/core/src/main/java/org/elasticsearch/search/aggregations/support/ValuesSource.java
+++ b/core/src/main/java/org/elasticsearch/search/aggregations/support/ValuesSource.java
@@ -22,7 +22,6 @@ import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.DocValues;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.index.SortedDocValues;
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.search.IndexSearcher;
@@ -32,18 +31,15 @@ import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.lucene.ScorerAware;
 import org.elasticsearch.index.fielddata.AbstractSortingNumericDocValues;
 import org.elasticsearch.index.fielddata.AtomicOrdinalsFieldData;
-import org.elasticsearch.index.fielddata.AtomicParentChildFieldData;
 import org.elasticsearch.index.fielddata.IndexFieldData;
 import org.elasticsearch.index.fielddata.IndexGeoPointFieldData;
 import org.elasticsearch.index.fielddata.IndexNumericFieldData;
 import org.elasticsearch.index.fielddata.IndexOrdinalsFieldData;
-import org.elasticsearch.index.fielddata.IndexParentChildFieldData;
 import org.elasticsearch.index.fielddata.MultiGeoPointValues;
 import org.elasticsearch.index.fielddata.SortedBinaryDocValues;
 import org.elasticsearch.index.fielddata.SortedNumericDoubleValues;
 import org.elasticsearch.index.fielddata.SortingBinaryDocValues;
 import org.elasticsearch.index.fielddata.SortingNumericDoubleValues;
-import org.elasticsearch.index.fielddata.plain.ParentChildIndexFieldData;
 import org.elasticsearch.script.LeafSearchScript;
 import org.elasticsearch.script.SearchScript;
 import org.elasticsearch.search.aggregations.support.ValuesSource.WithScript.BytesValues;
@@ -150,40 +146,6 @@ public abstract class ValuesSource {
             }
         }
 
-        public static class ParentChild extends Bytes {
-
-            protected final ParentChildIndexFieldData indexFieldData;
-
-            public ParentChild(ParentChildIndexFieldData indexFieldData) {
-                this.indexFieldData = indexFieldData;
-            }
-
-            public long globalMaxOrd(IndexSearcher indexSearcher, String type) {
-                DirectoryReader indexReader = (DirectoryReader) indexSearcher.getIndexReader();
-                if (indexReader.leaves().isEmpty()) {
-                    return 0;
-                } else {
-                    LeafReaderContext atomicReaderContext = indexReader.leaves().get(0);
-                    IndexParentChildFieldData globalFieldData = indexFieldData.loadGlobal(indexReader);
-                    AtomicParentChildFieldData afd = globalFieldData.load(atomicReaderContext);
-                    SortedDocValues values = afd.getOrdinalsValues(type);
-                    return values.getValueCount();
-                }
-            }
-
-            public SortedDocValues globalOrdinalsValues(String type, LeafReaderContext context) {
-                final IndexParentChildFieldData global = indexFieldData.loadGlobal((DirectoryReader)context.parent.reader());
-                final AtomicParentChildFieldData atomicFieldData = global.load(context);
-                return atomicFieldData.getOrdinalsValues(type);
-            }
-
-            @Override
-            public SortedBinaryDocValues bytesValues(LeafReaderContext context) {
-                final AtomicParentChildFieldData atomicFieldData = indexFieldData.load(context);
-                return atomicFieldData.getBytesValues();
-            }
-        }
-
         public static class FieldData extends Bytes {
 
             protected final IndexFieldData<?> indexFieldData;
diff --git a/core/src/main/java/org/elasticsearch/search/aggregations/support/ValuesSourceConfig.java b/core/src/main/java/org/elasticsearch/search/aggregations/support/ValuesSourceConfig.java
index 39b97a9b02..e5fac62840 100644
--- a/core/src/main/java/org/elasticsearch/search/aggregations/support/ValuesSourceConfig.java
+++ b/core/src/main/java/org/elasticsearch/search/aggregations/support/ValuesSourceConfig.java
@@ -26,7 +26,6 @@ import org.elasticsearch.index.fielddata.IndexFieldData;
 import org.elasticsearch.index.fielddata.IndexGeoPointFieldData;
 import org.elasticsearch.index.fielddata.IndexNumericFieldData;
 import org.elasticsearch.index.fielddata.IndexOrdinalsFieldData;
-import org.elasticsearch.index.fielddata.plain.ParentChildIndexFieldData;
 import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.query.QueryShardContext;
 import org.elasticsearch.script.Script;
@@ -317,9 +316,7 @@ public class ValuesSourceConfig<VS extends ValuesSource> {
     private ValuesSource bytesField() throws IOException {
         final IndexFieldData<?> indexFieldData = fieldContext().indexFieldData();
         ValuesSource dataSource;
-        if (indexFieldData instanceof ParentChildIndexFieldData) {
-            dataSource = new ValuesSource.Bytes.WithOrdinals.ParentChild((ParentChildIndexFieldData) indexFieldData);
-        } else if (indexFieldData instanceof IndexOrdinalsFieldData) {
+        if (indexFieldData instanceof IndexOrdinalsFieldData) {
             dataSource = new ValuesSource.Bytes.WithOrdinals.FieldData((IndexOrdinalsFieldData) indexFieldData);
         } else {
             dataSource = new ValuesSource.Bytes.FieldData(indexFieldData);