less duplication of hashmaps

* instead of building an ObjectValue for each hit (each with its
  own mapping of names->values) use a shared Hashlet.

3 files changed, 220 insertions, 17 deletions

diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/rpc/MatchFeatureData.java b/container-search/src/main/java/com/yahoo/search/dispatch/rpc/MatchFeatureData.java
new file mode 100644
index 00000000000..3a7a1796f04
--- /dev/null
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/rpc/MatchFeatureData.java
@@ -0,0 +1,98 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.search.dispatch.rpc;
+
+import com.yahoo.collections.Hashlet;
+
+import com.yahoo.data.access.ArrayTraverser;
+import com.yahoo.data.access.Inspector;
+import com.yahoo.data.access.ObjectTraverser;
+import com.yahoo.data.access.Type;
+import com.yahoo.data.access.simple.Value;
+
+import java.util.ArrayList;
+import java.util.AbstractMap.SimpleEntry;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * MatchFeatureData helps pack match features for hits into
+ * inspectable HitValue objects, all sharing the same Hashlet
+ * for the field names.
+ * @author arnej
+ */
+public class MatchFeatureData {
+
+    private final Hashlet<String,Integer> hashlet;
+
+    // package-private:
+    MatchFeatureData(List<String> keys) {
+        this.hashlet = new Hashlet<>();
+        hashlet.reserve(keys.size());
+        int i = 0;
+        for (String key : keys) {
+            hashlet.put(key, i++);
+        }
+    }
+
+    static class HitValue extends Value {
+        private final Hashlet<String,Integer> hashlet;
+        private final byte[][] dataValues;
+        private final double[] doubleValues;
+        private int index = 0;
+
+        public Type type() { return Type.OBJECT; }
+        public boolean valid() { return index == doubleValues.length; }
+        public int fieldCount() { return hashlet.size(); }
+        public void traverse(ObjectTraverser ot) {
+            for (int i = 0; i < hashlet.size(); i++) {
+                String fn = hashlet.key(i);
+                int offset = hashlet.value(i);
+                ot.field(fn, valueAt(offset));
+            }
+        }
+        public Inspector field(String name) {
+            int offset = hashlet.getIndexOfKey(name);
+            if (offset < 0 || ! valid()) {
+                return invalid();
+            }
+            return valueAt(offset);
+        }
+        public Iterable<Map.Entry<String,Inspector>> fields() {
+            if (! valid()) { return List.of(); }
+            var list = new ArrayList<Map.Entry<String,Inspector>>(hashlet.size());
+            for (int i = 0; i < hashlet.size(); i++) {
+                String fn = hashlet.key(i);
+                int offset = hashlet.value(i);
+                list.add(new SimpleEntry<String,Inspector>(fn, valueAt(offset)));
+            }
+            return list;
+        }
+
+        // use from enclosing class only
+        HitValue(Hashlet<String,Integer> hashlet) {
+            this.hashlet = hashlet;
+            this.dataValues = new byte[hashlet.size()][];
+            this.doubleValues = new double[hashlet.size()];
+        }
+
+        // package-private:
+        void add(byte[] data) {
+            dataValues[index++] = data;
+        }
+        void add(double value) {
+            doubleValues[index++] = value;
+        }
+
+        private Inspector valueAt(int index) {
+            if (dataValues[index] != null) {
+                return new Value.DataValue(dataValues[index]);
+            }
+            return new Value.DoubleValue(doubleValues[index]);
+        }
+    }
+
+    HitValue addHit() {
+        return new HitValue(hashlet);
+    }
+    
+}
diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/rpc/ProtobufSerialization.java b/container-search/src/main/java/com/yahoo/search/dispatch/rpc/ProtobufSerialization.java
index ac41321f639..8f8bfb63447 100644
--- a/container-search/src/main/java/com/yahoo/search/dispatch/rpc/ProtobufSerialization.java
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/rpc/ProtobufSerialization.java
@@ -197,7 +197,7 @@ public class ProtobufSerialization {
     }
 
     static InvokerResult convertToResult(Query query, SearchProtocol.SearchReply protobuf,
-                                                 DocumentDatabase documentDatabase, int partId, int distKey)
+                                         DocumentDatabase documentDatabase, int partId, int distKey)
     {
         InvokerResult result = new InvokerResult(query, protobuf.getHitsCount());
 
@@ -206,7 +206,8 @@ public class ProtobufSerialization {
 
         convertSearchReplyErrors(result.getResult(), protobuf.getErrorsList());
         List<String> featureNames = protobuf.getMatchFeatureNamesList();
-
+        var haveMatchFeatures = ! featureNames.isEmpty();
+        MatchFeatureData matchFeatures = haveMatchFeatures ? new MatchFeatureData(featureNames) : null;
         var haveGrouping = ! protobuf.getGroupingBlob().isEmpty();
         if (haveGrouping) {
             BufferSerializer buf = new BufferSerializer(new GrowableByteBuffer(protobuf.getGroupingBlob().asReadOnlyByteBuffer()));
@@ -221,27 +222,27 @@ public class ProtobufSerialization {
             hit.setQuery(query);
             result.getResult().hits().add(hit);
         }
-
+        int hitIndex = 0;
         for (var replyHit : protobuf.getHitsList()) {
             LeanHit hit = (replyHit.getSortData().isEmpty())
                     ? new LeanHit(replyHit.getGlobalId().toByteArray(), partId, distKey, replyHit.getRelevance())
                     : new LeanHit(replyHit.getGlobalId().toByteArray(), partId, distKey, replyHit.getRelevance(), replyHit.getSortData().toByteArray());
-            if (! featureNames.isEmpty()) {
-                List<SearchProtocol.Feature> featureValues = replyHit.getMatchFeaturesList();
-                var object = new Value.ObjectValue();
-                var nameIter = featureNames.iterator();
-                var valueIter = featureValues.iterator();
-                while (nameIter.hasNext() && valueIter.hasNext()) {
-                    String name = nameIter.next();
-                    SearchProtocol.Feature value = valueIter.next();
-                    ByteString tensorBlob = value.getTensor();
-                    if (tensorBlob.isEmpty()) {
-                        object.put(name, value.getNumber());
-                    } else {
-                        object.put(name, new Value.DataValue(tensorBlob.toByteArray()));
+            if (haveMatchFeatures) {
+                var hitFeatures = matchFeatures.addHit();
+                var featureList = replyHit.getMatchFeaturesList();
+                if (featureList.size() == featureNames.size()) {
+                    for (SearchProtocol.Feature value : featureList) {
+                        ByteString tensorBlob = value.getTensor();
+                        if (tensorBlob.isEmpty()) {
+                            hitFeatures.add(value.getNumber());
+                        } else {
+                            hitFeatures.add(tensorBlob.toByteArray());
+                        }
                     }
+                    hit.addMatchFeatures(hitFeatures);
+                } else {
+                    result.getResult().hits().addError(ErrorMessage.createBackendCommunicationError("mismatch in match feature sizes"));
                 }
-                hit.addMatchFeatures(object);
             }
             result.getLeanHits().add(hit);
         }
diff --git a/container-search/src/test/java/com/yahoo/search/dispatch/rpc/MatchFeatureDataTest.java b/container-search/src/test/java/com/yahoo/search/dispatch/rpc/MatchFeatureDataTest.java
new file mode 100644
index 00000000000..0ef6fbae062
--- /dev/null
+++ b/container-search/src/test/java/com/yahoo/search/dispatch/rpc/MatchFeatureDataTest.java
@@ -0,0 +1,104 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+package com.yahoo.search.dispatch.rpc;
+
+import com.yahoo.data.access.ArrayTraverser;
+import com.yahoo.data.access.Inspector;
+import com.yahoo.data.access.ObjectTraverser;
+import com.yahoo.data.access.Type;
+import org.junit.Test;
+
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * @author arnej
+ */
+public class MatchFeatureDataTest {
+
+    @Test
+    public void testHitValueAPI() {
+        List<String> names = List.of("foo", "bar", "baz", "qux", "quux");
+        var mf = new MatchFeatureData(names);
+        var hit = mf.addHit();
+        assertEquals(hit.type(), Type.OBJECT);
+        assertFalse(hit.valid());
+        hit.add(1.0);
+        hit.add(2.0);
+        byte[] somebytes = { 42, 0, 17 };
+        hit.add(somebytes);
+        hit.add(4.0);
+        assertFalse(hit.valid());
+        hit.add(5.0);
+        assertTrue(hit.valid());
+        assertEquals(0, hit.entryCount());
+        assertEquals(5, hit.fieldCount());
+        var f0 = hit.field("not");
+        assertFalse(f0.valid());
+
+        var f1 = hit.field("foo");
+        assertTrue(f1.valid());
+        assertEquals(f1.type(), Type.DOUBLE);
+        assertEquals(f1.asDouble(), 1.0, 0.0);
+
+        var f2 = hit.field("bar");
+        assertTrue(f2.valid());
+        assertEquals(f2.type(), Type.DOUBLE);
+        assertEquals(f2.asDouble(), 2.0, 0.0);
+
+        var f3 = hit.field("baz");
+        assertTrue(f3.valid());
+        assertEquals(f3.type(), Type.DATA);
+        var gotbytes = f3.asData();
+        assertEquals(3, gotbytes.length);
+        assertEquals(42, gotbytes[0]);
+        assertEquals(0,  gotbytes[1]);
+        assertEquals(17, gotbytes[2]);
+
+        var f5 = hit.field("quux");
+        assertTrue(f5.valid());
+        assertEquals(f5.type(), Type.DOUBLE);
+        assertEquals(f5.asDouble(), 5.0, 0.0);
+
+        var fields = hit.fields().iterator();
+        assertTrue(fields.hasNext());
+        Map.Entry<String,Inspector> entry = fields.next();
+        assertEquals("foo", entry.getKey());
+        assertEquals(f1.type(), entry.getValue().type());
+        assertEquals(f1.asDouble(), entry.getValue().asDouble(), 0.0);
+
+        assertTrue(fields.hasNext());
+        entry = fields.next();
+        assertEquals("bar", entry.getKey());
+
+        assertTrue(fields.hasNext());
+        entry = fields.next();
+        assertEquals("baz", entry.getKey());
+        assertEquals(f3.type(), entry.getValue().type());
+        assertEquals(f3.asData(), entry.getValue().asData());
+
+        assertTrue(fields.hasNext());
+        entry = fields.next();
+        assertEquals("qux", entry.getKey());
+        var f4 = entry.getValue();
+        assertTrue(f4.valid());
+        assertEquals(f4.type(), Type.DOUBLE);
+        assertEquals(f4.asDouble(), 4.0, 0.0);
+
+        assertTrue(fields.hasNext());
+        entry = fields.next();
+        assertEquals("quux", entry.getKey());
+        assertEquals(f5.type(), entry.getValue().type());
+        assertEquals(f5.asDouble(), entry.getValue().asDouble(), 0.0);
+
+        assertFalse(fields.hasNext());
+        
+        assertEquals("{\"foo\":1.0,\"bar\":2.0,\"baz\":\"0x2A0011\",\"qux\":4.0,\"quux\":5.0}",
+                     hit.toString());
+    }
+
+}