Write out during merging too

Author: thecoop

server/src/main/java/org/elasticsearch/index/codec/vectors/es93/ES93GenericFlatVectorsWriter.java

@@ -45,6 +45,7 @@ class ES93GenericFlatVectorsWriter extends FlatVectorsWriter {
         this.rawVectorFormatName = rawVectorsFormatName;
         this.useDirectIOReads = useDirectIOReads;
         this.rawVectorWriter = rawWriter;
+
         final String metaFileName = IndexFileNames.segmentFileName(state.segmentInfo.name, state.segmentSuffix, metaInfo.extension());
         try {
             this.metaOut = state.directory.createOutput(metaFileName, state.context);
@@ -71,24 +72,31 @@ public FlatFieldVectorsWriter<?> addField(FieldInfo fieldInfo) throws IOExceptio
     @Override
     public void mergeOneField(FieldInfo fieldInfo, MergeState mergeState) throws IOException {
         rawVectorWriter.mergeOneField(fieldInfo, mergeState);
+        writeMeta(fieldInfo.number);
     }
 
     @Override
     public CloseableRandomVectorScorerSupplier mergeOneFieldToIndex(FieldInfo fieldInfo, MergeState mergeState) throws IOException {
-        return rawVectorWriter.mergeOneFieldToIndex(fieldInfo, mergeState);
+        var supplier = rawVectorWriter.mergeOneFieldToIndex(fieldInfo, mergeState);
+        writeMeta(fieldInfo.number);
+        return supplier;
     }
 
     @Override
     public void flush(int maxDoc, Sorter.DocMap sortMap) throws IOException {
         rawVectorWriter.flush(maxDoc, sortMap);
 
         for (Integer field : fieldNumbers) {
-            metaOut.writeInt(field);
-            metaOut.writeString(rawVectorFormatName);
-            metaOut.writeByte(useDirectIOReads ? (byte) 1 : 0);
+            writeMeta(field);
         }
     }
 
+    private void writeMeta(int field) throws IOException {
+        metaOut.writeInt(field);
+        metaOut.writeString(rawVectorFormatName);
+        metaOut.writeByte(useDirectIOReads ? (byte) 1 : 0);
+    }
+
     @Override
     public void finish() throws IOException {
         rawVectorWriter.finish();

server/src/main/java/org/elasticsearch/index/mapper/MapperFeatures.java

@@ -50,9 +50,9 @@ public class MapperFeatures implements FeatureSpecification {
     static final NodeFeature SEARCH_LOAD_PER_SHARD = new NodeFeature("mapper.search_load_per_shard");
     static final NodeFeature PATTERN_TEXT = new NodeFeature("mapper.patterned_text");
     static final NodeFeature IGNORED_SOURCE_FIELDS_PER_ENTRY = new NodeFeature("mapper.ignored_source_fields_per_entry");
-    public static final NodeFeature MULTI_FIELD_UNICODE_OPTIMISATION_FIX = new NodeFeature("mapper.multi_field.unicode_optimisation_fix");
+    static final NodeFeature MULTI_FIELD_UNICODE_OPTIMISATION_FIX = new NodeFeature("mapper.multi_field.unicode_optimisation_fix");
     static final NodeFeature PATTERN_TEXT_RENAME = new NodeFeature("mapper.pattern_text_rename");
-    public static final NodeFeature DISKBBQ_ON_DISK_RESCORING = new NodeFeature("mapper.vectors.diskbbq_on_disk_rescoring");
+    static final NodeFeature DISKBBQ_ON_DISK_RESCORING = new NodeFeature("mapper.vectors.diskbbq_on_disk_rescoring");
 
     @Override
     public Set<NodeFeature> getTestFeatures() {