Add index_options to semantic_text field mappings

docs/changelog/119967.yaml

@@ -0,0 +1,5 @@
+pr: 119967
+summary: Add `index_options` to `semantic_text` field mappings
+area: Mapping
+type: enhancement
+issues: [ ]

docs/reference/mapping/types/semantic-text.asciidoc

@@ -96,6 +96,14 @@ You can update this parameter by using the <<indices-put-mapping, Update mapping
 Use the <<put-inference-api>> to create the endpoint.
 If not specified, the {infer} endpoint defined by `inference_id` will be used at both index and query time.
 
+`index_options`::
+(Optional, string) Specifies configurable index options for indexing documents.
+For dense vector models, the configuration of `index_options` uses the defined <<dense-vector-index-options>> configuration and defaults for dense vectors.
+There are currently no supported index options for sparse models.
+
+WARNING: Index options are not validated against inference IDs at index creation time.
+If index options are specified for a sparse vector model they will be ignored.
+
 [discrete]
 [[infer-endpoint-validation]]
 ==== {infer-cap} endpoint validation

server/src/main/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldMapper.java

@@ -88,6 +88,7 @@
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 import java.util.function.Function;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
@@ -284,6 +285,11 @@ public Builder elementType(ElementType elementType) {
             return this;
         }
 
+        public Builder indexOptions(IndexOptions indexOptions) {
+            this.indexOptions.setValue(indexOptions);
+            return this;
+        }
+
         @Override
         public DenseVectorFieldMapper build(MapperBuilderContext context) {
             // Validate again here because the dimensions or element type could have been set programmatically,
@@ -1182,7 +1188,7 @@ public final String toString() {
         public abstract VectorSimilarityFunction vectorSimilarityFunction(IndexVersion indexVersion, ElementType elementType);
     }
 
-    abstract static class IndexOptions implements ToXContent {
+    public abstract static class IndexOptions implements ToXContent {
         final VectorIndexType type;
 
         IndexOptions(VectorIndexType type) {
@@ -1230,7 +1236,7 @@ public final int hashCode() {
         }
     }
 
-    private enum VectorIndexType {
+    public enum VectorIndexType {
         HNSW("hnsw", false) {
             @Override
             public IndexOptions parseIndexOptions(String fieldName, Map<String, ?> indexOptionsMap) {
@@ -1257,6 +1263,11 @@ public boolean supportsElementType(ElementType elementType) {
             public boolean supportsDimension(int dims) {
                 return true;
             }
+
+            @Override
+            public Set<String> allowedOptions() {
+                return Set.of("m", "ef_construction");
+            }
         },
         INT8_HNSW("int8_hnsw", true) {
             @Override
@@ -1289,6 +1300,11 @@ public boolean supportsElementType(ElementType elementType) {
             public boolean supportsDimension(int dims) {
                 return true;
             }
+
+            @Override
+            public Set<String> allowedOptions() {
+                return Set.of("m", "ef_construction", "confidence_interval");
+            }
         },
         INT4_HNSW("int4_hnsw", true) {
             public IndexOptions parseIndexOptions(String fieldName, Map<String, ?> indexOptionsMap) {
@@ -1320,6 +1336,11 @@ public boolean supportsElementType(ElementType elementType) {
             public boolean supportsDimension(int dims) {
                 return dims % 2 == 0;
             }
+
+            @Override
+            public Set<String> allowedOptions() {
+                return Set.of("m", "ef_construction", "confidence_interval");
+            }
         },
         FLAT("flat", false) {
             @Override
@@ -1337,6 +1358,11 @@ public boolean supportsElementType(ElementType elementType) {
             public boolean supportsDimension(int dims) {
                 return true;
             }
+
+            @Override
+            public Set<String> allowedOptions() {
+                return Set.of();
+            }
         },
         INT8_FLAT("int8_flat", true) {
             @Override
@@ -1359,6 +1385,11 @@ public boolean supportsElementType(ElementType elementType) {
             public boolean supportsDimension(int dims) {
                 return true;
             }
+
+            @Override
+            public Set<String> allowedOptions() {
+                return Set.of("confidence_interval");
+            }
         },
         INT4_FLAT("int4_flat", true) {
             @Override
@@ -1381,6 +1412,11 @@ public boolean supportsElementType(ElementType elementType) {
             public boolean supportsDimension(int dims) {
                 return dims % 2 == 0;
             }
+
+            @Override
+            public Set<String> allowedOptions() {
+                return Set.of("confidence_interval");
+            }
         },
         BBQ_HNSW("bbq_hnsw", true) {
             @Override
@@ -1408,6 +1444,11 @@ public boolean supportsElementType(ElementType elementType) {
             public boolean supportsDimension(int dims) {
                 return dims >= BBQ_MIN_DIMS;
             }
+
+            @Override
+            public Set<String> allowedOptions() {
+                return Set.of("m", "ef_construction");
+            }
         },
         BBQ_FLAT("bbq_flat", true) {
             @Override
@@ -1425,9 +1466,14 @@ public boolean supportsElementType(ElementType elementType) {
             public boolean supportsDimension(int dims) {
                 return dims >= BBQ_MIN_DIMS;
             }
+
+            @Override
+            public Set<String> allowedOptions() {
+                return Set.of();
+            }
         };
 
-        static Optional<VectorIndexType> fromString(String type) {
+        public static Optional<VectorIndexType> fromString(String type) {
             return Stream.of(VectorIndexType.values()).filter(vectorIndexType -> vectorIndexType.name.equals(type)).findFirst();
         }
 
@@ -1439,12 +1485,14 @@ static Optional<VectorIndexType> fromString(String type) {
             this.quantized = quantized;
         }
 
-        abstract IndexOptions parseIndexOptions(String fieldName, Map<String, ?> indexOptionsMap);
+        public abstract IndexOptions parseIndexOptions(String fieldName, Map<String, ?> indexOptionsMap);
 
         public abstract boolean supportsElementType(ElementType elementType);
 
         public abstract boolean supportsDimension(int dims);
 
+        public abstract Set<String> allowedOptions();
+
         public boolean isQuantized() {
             return quantized;
         }
@@ -2321,7 +2369,7 @@ public FieldMapper.Builder getMergeBuilder() {
         return new Builder(leafName(), indexCreatedVersion).init(this);
     }
 
-    private static IndexOptions parseIndexOptions(String fieldName, Object propNode) {
+    public static IndexOptions parseIndexOptions(String fieldName, Object propNode) {
         @SuppressWarnings("unchecked")
         Map<String, ?> indexOptionsMap = (Map<String, ?>) propNode;
         Object typeNode = indexOptionsMap.remove("type");

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/InferenceFeatures.java

@@ -17,6 +17,7 @@
 
 import java.util.Set;
 
+import static org.elasticsearch.xpack.inference.mapper.SemanticTextFieldMapper.SEMANTIC_TEXT_INDEX_OPTIONS;
 import static org.elasticsearch.xpack.inference.queries.SemanticKnnVectorQueryRewriteInterceptor.SEMANTIC_KNN_VECTOR_QUERY_REWRITE_INTERCEPTION_SUPPORTED;
 import static org.elasticsearch.xpack.inference.queries.SemanticMatchQueryRewriteInterceptor.SEMANTIC_MATCH_QUERY_REWRITE_INTERCEPTION_SUPPORTED;
 import static org.elasticsearch.xpack.inference.queries.SemanticSparseVectorQueryRewriteInterceptor.SEMANTIC_SPARSE_VECTOR_QUERY_REWRITE_INTERCEPTION_SUPPORTED;
@@ -52,7 +53,8 @@ public Set<NodeFeature> getTestFeatures() {
             SEMANTIC_MATCH_QUERY_REWRITE_INTERCEPTION_SUPPORTED,
             SEMANTIC_SPARSE_VECTOR_QUERY_REWRITE_INTERCEPTION_SUPPORTED,
             SemanticInferenceMetadataFieldsMapper.EXPLICIT_NULL_FIXES,
-            SEMANTIC_KNN_VECTOR_QUERY_REWRITE_INTERCEPTION_SUPPORTED
+            SEMANTIC_KNN_VECTOR_QUERY_REWRITE_INTERCEPTION_SUPPORTED,
+            SEMANTIC_TEXT_INDEX_OPTIONS
         );
     }
 }