enhance: change autoindex default metric type (#34261)

issue: #34304 
cosine is more widely used in float vectors, and cosine and hamming
distance are 'metrics' which have good geometric properties

Signed-off-by: chasingegg <chao.gao@zilliz.com>

internal/datacoord/index_meta.go

@@ -187,11 +187,15 @@ func checkParams(fieldIndex *model.Index, req *indexpb.CreateIndexRequest) bool
 		return false
 	}
 
+	useAutoIndex := false
 	userIndexParamsWithoutMmapKey := make([]*commonpb.KeyValuePair, 0)
 	for _, param := range fieldIndex.UserIndexParams {
 		if param.Key == common.MmapEnabledKey {
 			continue
 		}
+		if param.Key == common.IndexTypeKey && param.Value == common.AutoIndexName {
+			useAutoIndex = true
+		}
 		userIndexParamsWithoutMmapKey = append(userIndexParamsWithoutMmapKey, param)
 	}
 
@@ -200,9 +204,24 @@ func checkParams(fieldIndex *model.Index, req *indexpb.CreateIndexRequest) bool
 	}
 	for _, param1 := range userIndexParamsWithoutMmapKey {
 		exist := false
-		for _, param2 := range req.GetUserIndexParams() {
+		for i, param2 := range req.GetUserIndexParams() {
 			if param2.Key == param1.Key && param2.Value == param1.Value {
 				exist = true
+			} else if param1.Key == common.MetricTypeKey && param2.Key == param1.Key && useAutoIndex && !req.GetUserAutoindexMetricTypeSpecified() {
+				// when users use autoindex, metric type is the only thing they can specify
+				// if they do not specify metric type, will use autoindex default metric type
+				// when autoindex default config upgraded, remain the old metric type at the very first time for compatibility
+				// warn! replace request metric type
+				log.Warn("user not specify autoindex metric type, autoindex config has changed, use old metric for compatibility",
+					zap.String("old metric type", param1.Value), zap.String("new metric type", param2.Value))
+				req.GetUserIndexParams()[i].Value = param1.Value
+				for j, param := range req.GetIndexParams() {
+					if param.Key == common.MetricTypeKey {
+						req.GetIndexParams()[j].Value = param1.Value
+						break
+					}
+				}
+				exist = true
 			}
 		}
 		if !exist {

internal/datacoord/index_meta_test.go

@@ -95,6 +95,20 @@ func TestMeta_CanCreateIndex(t *testing.T) {
 				Key:   common.IndexTypeKey,
 				Value: "FLAT",
 			},
+			{
+				Key:   common.MetricTypeKey,
+				Value: "L2",
+			},
+		}
+		userIndexParams = []*commonpb.KeyValuePair{
+			{
+				Key:   common.IndexTypeKey,
+				Value: common.AutoIndexName,
+			},
+			{
+				Key:   common.MetricTypeKey,
+				Value: "L2",
+			},
 		}
 	)
 
@@ -114,7 +128,7 @@ func TestMeta_CanCreateIndex(t *testing.T) {
 		IndexParams:     indexParams,
 		Timestamp:       0,
 		IsAutoIndex:     false,
-		UserIndexParams: indexParams,
+		UserIndexParams: userIndexParams,
 	}
 
 	t.Run("can create index", func(t *testing.T) {
@@ -132,7 +146,7 @@ func TestMeta_CanCreateIndex(t *testing.T) {
 			TypeParams:      typeParams,
 			IndexParams:     indexParams,
 			IsAutoIndex:     false,
-			UserIndexParams: indexParams,
+			UserIndexParams: userIndexParams,
 		}
 
 		err = m.CreateIndex(index)
@@ -166,6 +180,32 @@ func TestMeta_CanCreateIndex(t *testing.T) {
 		assert.Error(t, err)
 		assert.Equal(t, int64(0), tmpIndexID)
 
+		req.IndexParams = []*commonpb.KeyValuePair{{Key: common.IndexTypeKey, Value: "FLAT"}, {Key: common.MetricTypeKey, Value: "COSINE"}}
+		req.UserIndexParams = req.IndexParams
+		tmpIndexID, err = m.CanCreateIndex(req)
+		assert.Error(t, err)
+		assert.Equal(t, int64(0), tmpIndexID)
+
+		// when we use autoindex, it is possible autoindex changes default metric type
+		// if user does not specify metric type, we should follow the very first autoindex config
+		req.IndexParams = []*commonpb.KeyValuePair{{Key: common.IndexTypeKey, Value: "FLAT"}, {Key: common.MetricTypeKey, Value: "COSINE"}}
+		req.UserIndexParams = []*commonpb.KeyValuePair{{Key: common.IndexTypeKey, Value: "AUTOINDEX"}, {Key: common.MetricTypeKey, Value: "COSINE"}}
+		req.UserAutoindexMetricTypeSpecified = false
+		tmpIndexID, err = m.CanCreateIndex(req)
+		assert.NoError(t, err)
+		assert.Equal(t, indexID, tmpIndexID)
+		// req should follow the meta
+		assert.Equal(t, "L2", req.GetUserIndexParams()[1].Value)
+		assert.Equal(t, "L2", req.GetIndexParams()[1].Value)
+
+		// if autoindex specify metric type, so the index param change is from user, return error
+		req.IndexParams = []*commonpb.KeyValuePair{{Key: common.IndexTypeKey, Value: "FLAT"}, {Key: common.MetricTypeKey, Value: "COSINE"}}
+		req.UserIndexParams = []*commonpb.KeyValuePair{{Key: common.IndexTypeKey, Value: "AUTOINDEX"}, {Key: common.MetricTypeKey, Value: "COSINE"}}
+		req.UserAutoindexMetricTypeSpecified = true
+		tmpIndexID, err = m.CanCreateIndex(req)
+		assert.Error(t, err)
+		assert.Equal(t, int64(0), tmpIndexID)
+
 		req.IndexParams = indexParams
 		req.UserIndexParams = indexParams
 		req.FieldID++

internal/proto/index_coord.proto

@@ -163,6 +163,7 @@ message CreateIndexRequest {
     uint64 timestamp = 6;
     bool is_auto_index = 7;
     repeated common.KeyValuePair user_index_params = 8;
+    bool user_autoindex_metric_type_specified = 9;
 }
 
 message AlterIndexRequest {

internal/proxy/task_index.go

@@ -49,7 +49,7 @@ const (
 	GetIndexStateTaskName         = "GetIndexStateTask"
 	GetIndexBuildProgressTaskName = "GetIndexBuildProgressTask"
 
-	AutoIndexName = "AUTOINDEX"
+	AutoIndexName = common.AutoIndexName
 	DimKey        = common.DimKey
 	IsSparseKey   = common.IsSparseKey
 )
@@ -70,8 +70,9 @@ type createIndexTask struct {
 	newTypeParams  []*commonpb.KeyValuePair
 	newExtraParams []*commonpb.KeyValuePair
 
-	collectionID UniqueID
+	collectionID                     UniqueID
-	fieldSchema  *schemapb.FieldSchema
+	fieldSchema                      *schemapb.FieldSchema
+	userAutoIndexMetricTypeSpecified bool
 }
 
 func (cit *createIndexTask) TraceCtx() context.Context {
@@ -198,6 +199,7 @@ func (cit *createIndexTask) parseIndexParams() error {
 			if metricTypeExist {
 				// make the users' metric type first class citizen.
 				indexParamsMap[common.MetricTypeKey] = metricType
+				cit.userAutoIndexMetricTypeSpecified = true
 			}
 		} else { // behavior change after 2.2.9, adapt autoindex logic here.
 			useAutoIndex := func(autoIndexConfig map[string]string) {
@@ -235,6 +237,7 @@ func (cit *createIndexTask) parseIndexParams() error {
 					useAutoIndex(autoIndexConfig)
 					// make the users' metric type first class citizen.
 					indexParamsMap[common.MetricTypeKey] = metricType
+					cit.userAutoIndexMetricTypeSpecified = true
 				}
 
 				return nil
@@ -451,14 +454,15 @@ func (cit *createIndexTask) Execute(ctx context.Context) error {
 
 	var err error
 	req := &indexpb.CreateIndexRequest{
-		CollectionID:    cit.collectionID,
+		CollectionID:                     cit.collectionID,
-		FieldID:         cit.fieldSchema.GetFieldID(),
+		FieldID:                          cit.fieldSchema.GetFieldID(),
-		IndexName:       cit.req.GetIndexName(),
+		IndexName:                        cit.req.GetIndexName(),
-		TypeParams:      cit.newTypeParams,
+		TypeParams:                       cit.newTypeParams,
-		IndexParams:     cit.newIndexParams,
+		IndexParams:                      cit.newIndexParams,
-		IsAutoIndex:     cit.isAutoIndex,
+		IsAutoIndex:                      cit.isAutoIndex,
-		UserIndexParams: cit.newExtraParams,
+		UserIndexParams:                  cit.newExtraParams,
-		Timestamp:       cit.BeginTs(),
+		Timestamp:                        cit.BeginTs(),
+		UserAutoindexMetricTypeSpecified: cit.userAutoIndexMetricTypeSpecified,
 	}
 	cit.result, err = cit.datacoord.CreateIndex(ctx, req)
 	if err != nil {

internal/proxy/task_index_test.go

@@ -1006,6 +1006,7 @@ func Test_parseIndexParams_AutoIndex_WithType(t *testing.T) {
 		}
 		err := task.parseIndexParams()
 		assert.NoError(t, err)
+		assert.True(t, task.userAutoIndexMetricTypeSpecified)
 		assert.ElementsMatch(t, []*commonpb.KeyValuePair{
 			{Key: common.IndexTypeKey, Value: "HNSW"},
 			{Key: common.MetricTypeKey, Value: "L2"},
@@ -1026,6 +1027,7 @@ func Test_parseIndexParams_AutoIndex_WithType(t *testing.T) {
 		}
 		err := task.parseIndexParams()
 		assert.NoError(t, err)
+		assert.True(t, task.userAutoIndexMetricTypeSpecified)
 		assert.ElementsMatch(t, []*commonpb.KeyValuePair{
 			{Key: common.IndexTypeKey, Value: "SPARSE_INVERTED_INDEX"},
 			{Key: common.MetricTypeKey, Value: "IP"},
@@ -1044,6 +1046,7 @@ func Test_parseIndexParams_AutoIndex_WithType(t *testing.T) {
 		}
 		err := task.parseIndexParams()
 		assert.NoError(t, err)
+		assert.True(t, task.userAutoIndexMetricTypeSpecified)
 		assert.ElementsMatch(t, []*commonpb.KeyValuePair{
 			{Key: common.IndexTypeKey, Value: "BIN_IVF_FLAT"},
 			{Key: common.MetricTypeKey, Value: "JACCARD"},
@@ -1093,6 +1096,7 @@ func Test_parseIndexParams_AutoIndex(t *testing.T) {
 		}
 		err := task.parseIndexParams()
 		assert.NoError(t, err)
+		assert.False(t, task.userAutoIndexMetricTypeSpecified)
 		assert.ElementsMatch(t, []*commonpb.KeyValuePair{
 			{Key: common.IndexTypeKey, Value: AutoIndexName},
 			{Key: common.MetricTypeKey, Value: autoIndexConfigBinary[common.MetricTypeKey]},
@@ -1108,6 +1112,7 @@ func Test_parseIndexParams_AutoIndex(t *testing.T) {
 		}
 		err := task.parseIndexParams()
 		assert.NoError(t, err)
+		assert.False(t, task.userAutoIndexMetricTypeSpecified)
 		assert.ElementsMatch(t, []*commonpb.KeyValuePair{
 			{Key: common.IndexTypeKey, Value: AutoIndexName},
 			{Key: common.MetricTypeKey, Value: autoIndexConfigSparse[common.MetricTypeKey]},
@@ -1123,6 +1128,7 @@ func Test_parseIndexParams_AutoIndex(t *testing.T) {
 		}
 		err := task.parseIndexParams()
 		assert.NoError(t, err)
+		assert.False(t, task.userAutoIndexMetricTypeSpecified)
 		assert.ElementsMatch(t, []*commonpb.KeyValuePair{
 			{Key: common.IndexTypeKey, Value: AutoIndexName},
 			{Key: common.MetricTypeKey, Value: autoIndexConfig[common.MetricTypeKey]},
@@ -1140,6 +1146,7 @@ func Test_parseIndexParams_AutoIndex(t *testing.T) {
 		}
 		err := task.parseIndexParams()
 		assert.NoError(t, err)
+		assert.True(t, task.userAutoIndexMetricTypeSpecified)
 		assert.ElementsMatch(t, []*commonpb.KeyValuePair{
 			{Key: common.IndexTypeKey, Value: AutoIndexName},
 			{Key: common.MetricTypeKey, Value: "L2"},

pkg/common/common.go

@@ -121,6 +121,7 @@ const (
 
 	BitmapCardinalityLimitKey = "bitmap_cardinality_limit"
 	IsSparseKey               = "is_sparse"
+	AutoIndexName             = "AUTOINDEX"
 )
 
 //  Collection properties key

pkg/util/indexparamcheck/constraints.go

@@ -64,7 +64,7 @@ var (
 )
 
 const (
-	FloatVectorDefaultMetricType       = metric.IP
+	FloatVectorDefaultMetricType       = metric.COSINE
 	SparseFloatVectorDefaultMetricType = metric.IP
-	BinaryVectorDefaultMetricType      = metric.JACCARD
+	BinaryVectorDefaultMetricType      = metric.HAMMING
 )

pkg/util/indexparamcheck/hnsw_checker_test.go

@@ -180,15 +180,15 @@ func Test_hnswChecker_SetDefaultMetricType(t *testing.T) {
 	}{
 		{
 			dType:      schemapb.DataType_FloatVector,
-			metricType: metric.IP,
+			metricType: metric.COSINE,
 		},
 		{
 			dType:      schemapb.DataType_Float16Vector,
-			metricType: metric.IP,
+			metricType: metric.COSINE,
 		},
 		{
 			dType:      schemapb.DataType_BFloat16Vector,
-			metricType: metric.IP,
+			metricType: metric.COSINE,
 		},
 		{
 			dType:      schemapb.DataType_SparseFloatVector,
@@ -196,7 +196,7 @@ func Test_hnswChecker_SetDefaultMetricType(t *testing.T) {
 		},
 		{
 			dType:      schemapb.DataType_BinaryVector,
-			metricType: metric.JACCARD,
+			metricType: metric.HAMMING,
 		},
 	}
 

pkg/util/paramtable/autoindex_param.go

@@ -70,7 +70,7 @@ func (p *autoIndexConfig) init(base *BaseTable) {
 	p.IndexParams = ParamItem{
 		Key:          "autoIndex.params.build",
 		Version:      "2.2.0",
-		DefaultValue: `{"M": 18,"efConstruction": 240,"index_type": "HNSW", "metric_type": "IP"}`,
+		DefaultValue: `{"M": 18,"efConstruction": 240,"index_type": "HNSW", "metric_type": "COSINE"}`,
 		Export:       true,
 	}
 	p.IndexParams.Init(base.mgr)
@@ -86,7 +86,7 @@ func (p *autoIndexConfig) init(base *BaseTable) {
 	p.BinaryIndexParams = ParamItem{
 		Key:          "autoIndex.params.binary.build",
 		Version:      "2.4.5",
-		DefaultValue: `{"nlist": 1024, "index_type": "BIN_IVF_FLAT", "metric_type": "JACCARD"}`,
+		DefaultValue: `{"nlist": 1024, "index_type": "BIN_IVF_FLAT", "metric_type": "HAMMING"}`,
 		Export:       true,
 	}
 	p.BinaryIndexParams.Init(base.mgr)

tests/python_client/testcases/test_index.py

@@ -22,7 +22,8 @@ prefix = "index"
 default_schema = cf.gen_default_collection_schema()
 default_field_name = ct.default_float_vec_field_name
 default_index_params = ct.default_index
-default_autoindex_params = {"index_type": "AUTOINDEX", "metric_type": "IP"}
+default_autoindex_params = {"index_type": "AUTOINDEX", "metric_type": "COSINE"}
+default_sparse_autoindex_params = {"index_type": "AUTOINDEX", "metric_type": "IP"}
 
 # copied from pymilvus
 uid = "test_index"
@@ -2118,7 +2119,7 @@ class TestAutoIndex(TestcaseBase):
         """
         collection_w = self.init_collection_general(prefix, is_binary=True, is_index=False)[0]
         collection_w.create_index(binary_field_name, {})
-        assert collection_w.index()[0].params == {'index_type': 'AUTOINDEX', 'metric_type': 'JACCARD'}
+        assert collection_w.index()[0].params == {'index_type': 'AUTOINDEX', 'metric_type': 'HAMMING'}
 
     @pytest.mark.tags(CaseLabel.L1)
     def test_create_autoindex_on_all_vector_type(self):
@@ -2141,7 +2142,7 @@ class TestAutoIndex(TestcaseBase):
                    collection_w.index(index_name="bf16")[0].params.items())
 
         collection_w.create_index("sparse", index_name="sparse")
-        assert all(item in default_autoindex_params.items() for item in
+        assert all(item in default_sparse_autoindex_params.items() for item in
                    collection_w.index(index_name="sparse")[0].params.items())