Add raw sort values to SearchSortValues transport serialization (#36617)

In order for CCS alternate execution mode (see #32125) to be able to do the final reduction step on the CCS coordinating node, we need to serialize additional info in the transport layer as part of each `SearchHit`. Sort values are already present but they are formatted according to the provided `DocValueFormat` provided. The CCS node needs to be able to reconstruct the lucene `FieldDoc` to include in the `TopFieldDocs` and `CollapseTopFieldDocs` which will feed the `mergeTopDocs` method used to reduce multiple search responses (one per cluster) into one.

This commit adds such information to the `SearchSortValues` and exposes it through a new getter method added to `SearchHit` for retrieval. This info is only serialized at transport and never printed out at REST.

server/src/main/java/org/elasticsearch/search/SearchHit.java

@@ -19,16 +19,6 @@
 
 package org.elasticsearch.search;
 
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-
 import org.apache.lucene.search.Explanation;
 import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.action.OriginalIndices;
@@ -61,6 +51,16 @@ import org.elasticsearch.search.fetch.subphase.highlight.HighlightField;
 import org.elasticsearch.search.lookup.SourceLookup;
 import org.elasticsearch.transport.RemoteClusterAware;
 
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
 import static java.util.Collections.unmodifiableMap;
@@ -311,10 +311,17 @@ public final class SearchHit implements Streamable, ToXContentObject, Iterable<D
     }
 
     /**
-     * An array of the sort values used.
+     * An array of the (formatted) sort values used.
      */
     public Object[] getSortValues() {
-        return sortValues.sortValues();
+        return sortValues.getFormattedSortValues();
+    }
+
+    /**
+     * An array of the (raw) sort values used.
+     */
+    public Object[] getRawSortValues() {
+        return sortValues.getRawSortValues();
     }
 
     /**

server/src/main/java/org/elasticsearch/search/SearchSortValues.java

@@ -20,9 +20,11 @@
 package org.elasticsearch.search;
 
 import org.apache.lucene.util.BytesRef;
+import org.elasticsearch.Version;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.xcontent.ToXContentFragment;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
@@ -35,101 +37,56 @@ import java.util.Objects;
 
 public class SearchSortValues implements ToXContentFragment, Writeable {
 
-    static final SearchSortValues EMPTY = new SearchSortValues(new Object[0]);
-    private final Object[] sortValues;
+    private static final Object[] EMPTY_ARRAY = new Object[0];
+    static final SearchSortValues EMPTY = new SearchSortValues(EMPTY_ARRAY);
+
+    private final Object[] formattedSortValues;
+    private final Object[] rawSortValues;
 
     SearchSortValues(Object[] sortValues) {
-        this.sortValues = Objects.requireNonNull(sortValues, "sort values must not be empty");
+        this.formattedSortValues = Objects.requireNonNull(sortValues, "sort values must not be empty");
+        this.rawSortValues = EMPTY_ARRAY;
     }
 
-    public SearchSortValues(Object[] sortValues, DocValueFormat[] sortValueFormats) {
-        Objects.requireNonNull(sortValues);
+    public SearchSortValues(Object[] rawSortValues, DocValueFormat[] sortValueFormats) {
+        Objects.requireNonNull(rawSortValues);
         Objects.requireNonNull(sortValueFormats);
-        this.sortValues = Arrays.copyOf(sortValues, sortValues.length);
-        for (int i = 0; i < sortValues.length; ++i) {
-            if (this.sortValues[i] instanceof BytesRef) {
-                this.sortValues[i] = sortValueFormats[i].format((BytesRef) sortValues[i]);
+        if (rawSortValues.length != sortValueFormats.length) {
+            throw new IllegalArgumentException("formattedSortValues and sortValueFormats must hold the same number of items");
+        }
+        this.rawSortValues = rawSortValues;
+        this.formattedSortValues = Arrays.copyOf(rawSortValues, rawSortValues.length);
+        for (int i = 0; i < rawSortValues.length; ++i) {
+            //we currently format only BytesRef but we may want to change that in the future
+            Object sortValue = rawSortValues[i];
+            if (sortValue instanceof BytesRef) {
+                this.formattedSortValues[i] = sortValueFormats[i].format((BytesRef) sortValue);
             }
         }
     }
 
-    public SearchSortValues(StreamInput in) throws IOException {
-        int size = in.readVInt();
-        if (size > 0) {
-            sortValues = new Object[size];
-            for (int i = 0; i < sortValues.length; i++) {
-                byte type = in.readByte();
-                if (type == 0) {
-                    sortValues[i] = null;
-                } else if (type == 1) {
-                    sortValues[i] = in.readString();
-                } else if (type == 2) {
-                    sortValues[i] = in.readInt();
-                } else if (type == 3) {
-                    sortValues[i] = in.readLong();
-                } else if (type == 4) {
-                    sortValues[i] = in.readFloat();
-                } else if (type == 5) {
-                    sortValues[i] = in.readDouble();
-                } else if (type == 6) {
-                    sortValues[i] = in.readByte();
-                } else if (type == 7) {
-                    sortValues[i] = in.readShort();
-                } else if (type == 8) {
-                    sortValues[i] = in.readBoolean();
-                } else {
-                    throw new IOException("Can't match type [" + type + "]");
-                }
-            }
+    SearchSortValues(StreamInput in) throws IOException {
+        this.formattedSortValues = in.readArray(Lucene::readSortValue, Object[]::new);
+        if (in.getVersion().onOrAfter(Version.V_7_0_0)) {
+            this.rawSortValues = in.readArray(Lucene::readSortValue, Object[]::new);
         } else {
-            sortValues = new Object[0];
+            this.rawSortValues = EMPTY_ARRAY;
         }
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeVInt(sortValues.length);
-        for (Object sortValue : sortValues) {
-            if (sortValue == null) {
-                out.writeByte((byte) 0);
-            } else {
-                Class type = sortValue.getClass();
-                if (type == String.class) {
-                    out.writeByte((byte) 1);
-                    out.writeString((String) sortValue);
-                } else if (type == Integer.class) {
-                    out.writeByte((byte) 2);
-                    out.writeInt((Integer) sortValue);
-                } else if (type == Long.class) {
-                    out.writeByte((byte) 3);
-                    out.writeLong((Long) sortValue);
-                } else if (type == Float.class) {
-                    out.writeByte((byte) 4);
-                    out.writeFloat((Float) sortValue);
-                } else if (type == Double.class) {
-                    out.writeByte((byte) 5);
-                    out.writeDouble((Double) sortValue);
-                } else if (type == Byte.class) {
-                    out.writeByte((byte) 6);
-                    out.writeByte((Byte) sortValue);
-                } else if (type == Short.class) {
-                    out.writeByte((byte) 7);
-                    out.writeShort((Short) sortValue);
-                } else if (type == Boolean.class) {
-                    out.writeByte((byte) 8);
-                    out.writeBoolean((Boolean) sortValue);
-                } else {
-                    throw new IOException("Can't handle sort field value of type [" + type + "]");
-                }
-            }
+        out.writeArray(Lucene::writeSortValue, this.formattedSortValues);
+        if (out.getVersion().onOrAfter(Version.V_7_0_0)) {
+            out.writeArray(Lucene::writeSortValue, this.rawSortValues);
         }
     }
 
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-        if (sortValues.length > 0) {
+        if (formattedSortValues.length > 0) {
             builder.startArray(Fields.SORT);
-            for (Object sortValue : sortValues) {
+            for (Object sortValue : formattedSortValues) {
                 builder.value(sortValue);
             }
             builder.endArray();
@@ -142,24 +99,37 @@ public class SearchSortValues implements ToXContentFragment, Writeable {
         return new SearchSortValues(parser.list().toArray());
     }
 
-    public Object[] sortValues() {
-        return sortValues;
+    /**
+     * Returns the formatted version of the values that sorting was performed against
+     */
+    public Object[] getFormattedSortValues() {
+        return formattedSortValues;
+    }
+
+    /**
+     * Returns the raw version of the values that sorting was performed against
+     */
+    public Object[] getRawSortValues() {
+        return rawSortValues;
     }
 
     @Override
-    public boolean equals(Object obj) {
-        if (this == obj) {
+    public boolean equals(Object o) {
+        if (this == o) {
             return true;
         }
-        if (obj == null || getClass() != obj.getClass()) {
+        if (o == null || getClass() != o.getClass()) {
             return false;
         }
-        SearchSortValues other = (SearchSortValues) obj;
-        return Arrays.equals(sortValues, other.sortValues);
+        SearchSortValues that = (SearchSortValues) o;
+        return Arrays.equals(formattedSortValues, that.formattedSortValues) &&
+            Arrays.equals(rawSortValues, that.rawSortValues);
     }
 
     @Override
     public int hashCode() {
-        return Arrays.hashCode(sortValues);
+        int result = Arrays.hashCode(formattedSortValues);
+        result = 31 * result + Arrays.hashCode(rawSortValues);
+        return result;
     }
 }

server/src/test/java/org/elasticsearch/common/lucene/LuceneTests.java

@@ -531,24 +531,26 @@ public class LuceneTests extends ESTestCase {
     }
 
     public static Object randomSortValue() {
-        switch(randomIntBetween(0, 8)) {
+        switch(randomIntBetween(0, 9)) {
             case 0:
-                return randomAlphaOfLengthBetween(3, 10);
+                return null;
             case 1:
-                return randomInt();
+                return randomAlphaOfLengthBetween(3, 10);
             case 2:
-                return randomLong();
+                return randomInt();
             case 3:
-                return randomFloat();
+                return randomLong();
             case 4:
-                return randomDouble();
+                return randomFloat();
             case 5:
-                return randomByte();
+                return randomDouble();
             case 6:
-                return randomShort();
+                return randomByte();
             case 7:
-                return randomBoolean();
+                return randomShort();
             case 8:
+                return randomBoolean();
+            case 9:
                 return new BytesRef(randomAlphaOfLengthBetween(3, 10));
             default:
                 throw new UnsupportedOperationException();

server/src/test/java/org/elasticsearch/search/SearchSortValuesTests.java

@@ -22,6 +22,7 @@ package org.elasticsearch.search;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.Version;
 import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.Writeable;
 import org.elasticsearch.common.lucene.LuceneTests;
 import org.elasticsearch.common.xcontent.ToXContent;
@@ -31,23 +32,36 @@ import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.json.JsonXContent;
 import org.elasticsearch.test.AbstractSerializingTestCase;
 import org.elasticsearch.test.RandomObjects;
+import org.elasticsearch.test.VersionUtils;
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Base64;
 
 public class SearchSortValuesTests extends AbstractSerializingTestCase<SearchSortValues> {
 
     public static SearchSortValues createTestItem(XContentType xContentType, boolean transportSerialization) {
         int size = randomIntBetween(1, 20);
         Object[] values = new Object[size];
-        DocValueFormat[] sortValueFormats = new DocValueFormat[size];
-        for (int i = 0; i < size; i++) {
-            Object sortValue = randomSortValue(xContentType, transportSerialization);
-            values[i] = sortValue;
-            //make sure that for BytesRef, we provide a specific doc value format that overrides format(BytesRef)
-            sortValueFormats[i] = sortValue instanceof BytesRef ? DocValueFormat.RAW : randomDocValueFormat();
+        if (transportSerialization) {
+            DocValueFormat[] sortValueFormats = new DocValueFormat[size];
+            for (int i = 0; i < size; i++) {
+                Object sortValue = randomSortValue(xContentType, transportSerialization);
+                values[i] = sortValue;
+                //make sure that for BytesRef, we provide a specific doc value format that overrides format(BytesRef)
+                sortValueFormats[i] = sortValue instanceof BytesRef ? DocValueFormat.RAW : randomDocValueFormat();
+            }
+            return new SearchSortValues(values, sortValueFormats);
+        } else {
+            //xcontent serialization doesn't write/parse the raw sort values, only the formatted ones
+            for (int i = 0; i < size; i++) {
+                Object sortValue = randomSortValue(xContentType, transportSerialization);
+                //make sure that BytesRef are not provided as formatted values
+                sortValue = sortValue instanceof BytesRef ? DocValueFormat.RAW.format((BytesRef)sortValue) : sortValue;
+                values[i] = sortValue;
+            }
+            return new SearchSortValues(values);
         }
-        return new SearchSortValues(values, sortValueFormats);
     }
 
     private static Object randomSortValue(XContentType xContentType, boolean transportSerialization) {
@@ -79,7 +93,7 @@ public class SearchSortValuesTests extends AbstractSerializingTestCase<SearchSor
 
     @Override
     protected SearchSortValues createTestInstance() {
-        return createTestItem(randomFrom(XContentType.values()), true);
+        return createTestItem(randomFrom(XContentType.values()), randomBoolean());
     }
 
     @Override
@@ -113,20 +127,32 @@ public class SearchSortValuesTests extends AbstractSerializingTestCase<SearchSor
 
     @Override
     protected SearchSortValues mutateInstance(SearchSortValues instance) {
-        Object[] sortValues = instance.sortValues();
-        if (sortValues.length == 0) {
-            return createTestInstance();
-        }
+        Object[] sortValues = instance.getFormattedSortValues();
         if (randomBoolean()) {
             return new SearchSortValues(new Object[0]);
         }
         Object[] values = Arrays.copyOf(sortValues, sortValues.length + 1);
-        values[sortValues.length] = randomSortValue(randomFrom(XContentType.values()), true);
+        values[sortValues.length] = randomSortValue(randomFrom(XContentType.values()), randomBoolean());
         return new SearchSortValues(values);
     }
 
-    @Override
-    protected SearchSortValues copyInstance(SearchSortValues instance, Version version) {
-        return new SearchSortValues(Arrays.copyOf(instance.sortValues(), instance.sortValues().length));
+    //TODO rename and update version after backport
+    public void testSerializationPre70() throws IOException {
+        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, VersionUtils.getPreviousVersion(Version.V_7_0_0));
+        SearchSortValues original = createTestInstance();
+        SearchSortValues deserialized = copyInstance(original, version);
+        assertArrayEquals(original.getFormattedSortValues(), deserialized.getFormattedSortValues());
+        assertEquals(0, deserialized.getRawSortValues().length);
+    }
+
+    //TODO rename method and adapt versions after backport
+    public void testReadFromPre70() throws IOException {
+        try (StreamInput in = StreamInput.wrap(Base64.getDecoder().decode("AwIAAAABAQEyBUAIAAAAAAAAAAAAAAAA"))) {
+            in.setVersion(VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, VersionUtils.getPreviousVersion(Version.V_7_0_0)));
+            SearchSortValues deserialized = new SearchSortValues(in);
+            SearchSortValues expected = new SearchSortValues(new Object[]{1, "2", 3d});
+            assertEquals(expected, deserialized);
+            assertEquals(0, deserialized.getRawSortValues().length);
+        }
     }
 }

test/framework/src/main/java/org/elasticsearch/test/AbstractWireSerializingTestCase.java

@@ -27,6 +27,6 @@ public abstract class AbstractWireSerializingTestCase<T extends Writeable> exten
 
     @Override
     protected T copyInstance(T instance, Version version) throws IOException {
-        return copyWriteable(instance, getNamedWriteableRegistry(), instanceReader());
+        return copyWriteable(instance, getNamedWriteableRegistry(), instanceReader(), version);
     }
 }