fix: make Milvus vector metric type configurable via MILVUS_METRIC_TYPE

Author: Dounx

.env.example

@@ -267,6 +267,10 @@ APK_MIRROR_ARG=mirrors.tencent.com
 # Milvus集合名称，用于存储向量数据
 # MILVUS_COLLECTION=weknora_embeddings
 
+# Milvus向量搜索度量类型，支持 IP(默认)、COSINE、L2
+# 注意：修改度量类型后需要重建collection才能生效
+# MILVUS_METRIC_TYPE=IP
+
 # Milvus 用户名(可选）
 # MILVUS_USERNAME=your_milvus_username
 

docker-compose.yml

@@ -84,6 +84,7 @@ services:
       - QDRANT_USE_TLS=${QDRANT_USE_TLS:-false}
       - MILVUS_ADDRESS=milvus:19530
       - MILVUS_COLLECTION=${MILVUS_COLLECTION:-weknora_embeddings}
+      - MILVUS_METRIC_TYPE=${MILVUS_METRIC_TYPE:-IP}
       - DOCREADER_ADDR=${DOCREADER_ADDR:-docreader:50051}
       - DOCREADER_TRANSPORT=${DOCREADER_TRANSPORT:-grpc}
       - WEAVIATE_HOST=${WEAVIATE_HOST:-weaviate:8080}

internal/application/repository/retriever/milvus/repository.go

@@ -21,6 +21,7 @@ import (
 
 const (
 	envMilvusCollection   = "MILVUS_COLLECTION"
+	envMilvusMetricType   = "MILVUS_METRIC_TYPE"
 	defaultCollectionName = "weknora_embeddings"
 	fieldContent          = "content"
 	fieldSourceID         = "source_id"
@@ -51,10 +52,26 @@ func NewMilvusRetrieveEngineRepository(client *client.Client) interfaces.Retriev
 		collectionBaseName = defaultCollectionName
 	}
 
+	metricType := entity.IP
+	if mt := os.Getenv(envMilvusMetricType); mt != "" {
+		switch strings.ToUpper(mt) {
+		case "COSINE":
+			metricType = entity.COSINE
+		case "L2":
+			metricType = entity.L2
+		case "IP":
+			metricType = entity.IP
+		default:
+			log.Warnf("[Milvus] Unknown MILVUS_METRIC_TYPE '%s', using default IP", mt)
+		}
+	}
+	log.Infof("[Milvus] Using metric type: %s", metricType)
+
 	res := &milvusRepository{
 		filter:             filter{},
 		client:             client,
 		collectionBaseName: collectionBaseName,
+		metricType:         metricType,
 	}
 
 	log.Info("[Milvus] Successfully initialized repository")
@@ -150,7 +167,7 @@ func (m *milvusRepository) ensureCollection(ctx context.Context, dimension int)
 
 		indexOpts := make([]client.CreateIndexOption, 0)
 		// hnsw index for embedding field
-		indexOpts = append(indexOpts, client.NewCreateIndexOption(collectionName, fieldEmbedding, index.NewHNSWIndex(entity.IP, 16, 128)))
+		indexOpts = append(indexOpts, client.NewCreateIndexOption(collectionName, fieldEmbedding, index.NewHNSWIndex(m.metricType, 16, 128)))
 		indexOpts = append(indexOpts, client.NewCreateIndexOption(collectionName, fieldContentSparse, index.NewAutoIndex(entity.BM25)))
 		// Create payload indexes for filtering
 		indexFields := []string{fieldChunkID, fieldKnowledgeID, fieldKnowledgeBaseID, fieldSourceID, fieldIsEnabled}

internal/application/repository/retriever/milvus/structs.go

@@ -3,13 +3,15 @@ package milvus
 import (
 	"sync"
 
+	"github.com/milvus-io/milvus/client/v2/entity"
 	client "github.com/milvus-io/milvus/client/v2/milvusclient"
 )
 
 type milvusRepository struct {
 	filter
 	client             *client.Client
 	collectionBaseName string
+	metricType         entity.MetricType
 	// Cache for initialized collections (dimension -> true)
 	initializedCollections sync.Map
 }