Support FunctionScore, multi-reranker for search/hybridSearch (milvus-io#1588)

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

Author: yhmo

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

@@ -31,6 +31,7 @@
 import io.milvus.v2.service.collection.request.CreateCollectionReq;
 import io.milvus.v2.service.collection.request.DropCollectionReq;
 import io.milvus.v2.service.vector.request.AnnSearchReq;
+import io.milvus.v2.service.vector.request.FunctionScore;
 import io.milvus.v2.service.vector.request.HybridSearchReq;
 import io.milvus.v2.service.vector.request.InsertReq;
 import io.milvus.v2.service.vector.request.QueryReq;
@@ -122,7 +123,6 @@ private void createCollection() {
                 .metricType(BINARY_VECTOR_METRIC)
                 .build());
         Map<String,Object> fv16Params = new HashMap<>();
-        fv16Params.clear();
         fv16Params.put("M",16);
         fv16Params.put("efConstruction",64);
         indexes.add(IndexParam.builder()
@@ -212,7 +212,9 @@ private void hybridSearch() {
         HybridSearchReq hybridSearchReq = HybridSearchReq.builder()
                 .collectionName(COLLECTION_NAME)
                 .searchRequests(searchRequests)
-                .ranker(WeightedRanker.builder().weights(Arrays.asList(0.2f, 0.5f, 0.6f)).build())
+                .functionScore(FunctionScore.builder()
+                        .addFunction(WeightedRanker.builder().weights(Arrays.asList(0.2f, 0.5f, 0.6f)).build())
+                        .build())
                 .limit(5)
                 .consistencyLevel(ConsistencyLevel.BOUNDED)
                 .build();

sdk-core/src/main/java/io/milvus/orm/iterator/QueryIterator.java

@@ -210,8 +210,10 @@ private boolean isResSufficient(List<QueryResultsWrapper.RowRecord> ret) {
     private QueryResults executeQuery(String expr, long offset, long limit, long ts, boolean isSeek) {
         // for seeking offset, no need to return output fields
         List<String> outputFields = new ArrayList<>();
+        boolean reduceStopForBest = queryIteratorParam.isReduceStopForBest();
         if (!isSeek) {
             outputFields = queryIteratorParam.getOutFields();
+            reduceStopForBest = false;
         }
         QueryParam queryParam = QueryParam.newBuilder()
                 .withDatabaseName(queryIteratorParam.getDatabaseName())
@@ -230,7 +232,7 @@ private QueryResults executeQuery(String expr, long offset, long limit, long ts,
         // reduce stop for best
         builder.addQueryParams(KeyValuePair.newBuilder()
                 .setKey(Constant.REDUCE_STOP_FOR_BEST)
-                .setValue(String.valueOf(queryIteratorParam.isReduceStopForBest()))
+                .setValue(String.valueOf(reduceStopForBest))
                 .build());
 
         // iterator

sdk-core/src/main/java/io/milvus/v2/service/collection/request/CreateCollectionReq.java

@@ -69,7 +69,7 @@ private CreateCollectionReq(Builder builder) {
         if (builder.collectionName == null) {
             throw new IllegalArgumentException("Collection name cannot be null");
         }
-        
+
         this.databaseName = builder.databaseName;
         this.collectionName = builder.collectionName;
         this.description = builder.description;

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

@@ -0,0 +1,50 @@
+/*
+ * 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;
+
+import io.milvus.v2.service.collection.request.CreateCollectionReq;
+import lombok.Builder;
+import lombok.Data;
+import lombok.experimental.SuperBuilder;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+@Data
+@SuperBuilder
+public class FunctionScore {
+    @Builder.Default
+    private List<CreateCollectionReq.Function> functions = new ArrayList<>();
+    @Builder.Default
+    private Map<String, String> params = new HashMap<>();
+
+    public static abstract class FunctionScoreBuilder<C extends FunctionScore, B extends FunctionScore.FunctionScoreBuilder<C, B>> {
+        public B addFunction(CreateCollectionReq.Function func) {
+            if(null == this.functions$value ){
+                this.functions$value = new ArrayList<>();
+            }
+            this.functions$value.add(func);
+            this.functions$set = true;
+            return self();
+        }
+    }
+}