Support NGRAM and BoostRanker

Signed-off-by: yhmo <yihua.mo@zilliz.com>

Author: yhmo

examples/src/main/java/io/milvus/v2/JsonFieldExample.java

@@ -98,6 +98,32 @@ public static void main(String[] args) {
                 .metricType(IndexParam.MetricType.COSINE)
                 .build());
 
+        // Create INVERTED index for a specific entry of JSON field
+        // Index for JSON field is supported from milvus v2.5.7 and fully supported in v2.5.13+
+        // Read the doc for more info: https://milvus.io/docs/json-indexing.md
+        Map<String,Object> p1 = new HashMap<>();
+        p1.put("json_path", "metadata[\"flags\"]");
+        p1.put("json_cast_type", "array_double");
+        indexes.add(IndexParam.builder()
+                .fieldName(JSON_FIELD)
+                .indexType(IndexParam.IndexType.INVERTED)
+                .extraParams(p1)
+                .build());
+
+        // Create NGRAM index for a specific entry of JSON field
+        // NGRAM index for JSON field is supported from milvus v2.6.2
+        // Read the doc for more info: https://milvus.io/docs/ngram.md
+        Map<String,Object> p2 = new HashMap<>();
+        p2.put("json_path","metadata[\"path\"]");
+        p2.put("json_cast_type", "varchar");
+        p2.put("min_gram", 3);
+        p2.put("max_gram", 5);
+        indexes.add(IndexParam.builder()
+                .fieldName(JSON_FIELD)
+                .indexType(IndexParam.IndexType.NGRAM)
+                .extraParams(p2)
+                .build());
+
         CreateCollectionReq requestCreate = CreateCollectionReq.builder()
                 .collectionName(COLLECTION_NAME)
                 .collectionSchema(collectionSchema)
@@ -121,7 +147,7 @@ public static void main(String[] args) {
             // Note: for JSON field, always construct a real JsonObject
             // don't use row.addProperty(JSON_FIELD, strContent) since the value is treated as a string, not a JsonObject
             JsonObject metadata = new JsonObject();
-            metadata.addProperty("path", String.format("\\root/abc/path_%d", i));
+            metadata.addProperty("path", String.format("\\root/abc_%d/path_%d", i, i));
             metadata.addProperty("size", i);
             if (i%7 == 0) {
                 metadata.addProperty("special", true);
@@ -197,6 +223,7 @@ public static void main(String[] args) {
         queryWithExpr(client, "JSON_CONTAINS(metadata[\"flags\"], 9)");
         queryWithExpr(client, "JSON_CONTAINS_ANY(metadata[\"flags\"], [8, 9, 10])");
         queryWithExpr(client, "JSON_CONTAINS_ALL(metadata[\"flags\"], [8, 9, 10])");
+        queryWithExpr(client, "metadata[\"path\"] LIKE \"%c_5%\"");
         queryWithExpr(client, "dynamic1 < 2.0");
 
         client.close();

sdk-core/src/main/java/io/milvus/v2/common/IndexParam.java

@@ -89,12 +89,15 @@ public enum IndexType {
         // Only for varchar type field
         TRIE("Trie", 100),
 
+        // Only for varchar type field and json_path of JSON field
+        NGRAM(101),
+
         // Only for geometry type field
-        RTREE("RTREE", 120),
+        RTREE(120),
 
         // Only for scalar type field
         STL_SORT(200), // only for numeric type field
-        INVERTED(201), // works for all scalar fields except JSON type field
+        INVERTED(201), // works for all scalar fields and json_path of JSON field
         BITMAP(202), // works for all scalar fields except JSON, FLOAT and DOUBLE type fields
 
         // Only for sparse vectors

sdk-core/src/main/java/io/milvus/v2/service/vector/request/ranker/BoostRanker.java

@@ -0,0 +1,79 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF 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 io.milvus.v2.service.vector.request.ranker;
+
+import io.milvus.common.clientenum.FunctionType;
+import io.milvus.common.utils.JsonUtils;
+import io.milvus.v2.service.collection.request.CreateCollectionReq;
+import lombok.experimental.SuperBuilder;
+import org.apache.commons.lang3.StringUtils;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * The Decay reranking strategy, which by adjusting search rankings based on numeric field values.
+ * Read the doc for more info: https://milvus.io/docs/decay-ranker-overview.md
+ *
+ * You also can declare a decay ranker by Function
+ * CreateCollectionReq.Function rr = CreateCollectionReq.Function.builder()
+ *                 .functionType(FunctionType.RERANK)
+ *                 .name("xxx_boost")
+ *                 .description("random on xxx")
+ *                 .param("reranker", "boost")
+ *                 .param("filter", "xx == 2")
+ *                 .param("weight", "0.5")
+ *                 .param("random_score", "{\"seed\": 123, \"field\": \"id\"}")
+ *                 .build();
+ */
+@SuperBuilder
+public class BoostRanker extends CreateCollectionReq.Function {
+    private String filter;
+    private Float weight;
+    private Long randomScoreSeed;
+    private String randomScoreField;
+
+    public FunctionType getFunctionType() {
+        return FunctionType.RERANK;
+    }
+
+    public Map<String, String> getParams() {
+        Map<String, String> props = super.getParams();
+        props.put("reranker", "boost");
+        if (!StringUtils.isEmpty(filter)) {
+            props.put("filter", filter);
+        }
+        if (weight != null) {
+            props.put("weight", weight.toString());
+        }
+
+        Map<String, Object> randomScore = new HashMap<>();
+        if (randomScoreSeed != null) {
+            randomScore.put("seed", randomScoreSeed);
+        }
+        if (!StringUtils.isEmpty(randomScoreField)) {
+            randomScore.put("field", randomScoreField);
+        }
+        if (!randomScore.isEmpty()) {
+            props.put("random_score", JsonUtils.toJson(randomScore));
+        }
+        return props;
+    }
+}