fix: alter collection failed with MMAP setting for STRUCT (#45173)

issue: https://github.com/milvus-io/milvus/issues/45001
ref: https://github.com/milvus-io/milvus/issues/42148

---------

Signed-off-by: SpadeA <tangchenjie1210@gmail.com>
Signed-off-by: aoiasd <zhicheng.yue@zilliz.com>
Signed-off-by: SpadeA-Tang <tangchenjie1210@gmail.com>
Co-authored-by: aoiasd <zhicheng.yue@zilliz.com>

internal/metastore/model/struct_field.go

@@ -1,7 +1,9 @@
 package model
 
 import (
+	"github.com/milvus-io/milvus-proto/go-api/v2/commonpb"
 	"github.com/milvus-io/milvus-proto/go-api/v2/schemapb"
+	"github.com/milvus-io/milvus/pkg/v2/common"
 )
 
 type StructArrayField struct {
@@ -9,6 +11,7 @@ type StructArrayField struct {
 	Name        string
 	Description string
 	Fields      []*Field
+	TypeParams  []*commonpb.KeyValuePair
 }
 
 func (s *StructArrayField) Clone() *StructArrayField {
@@ -17,6 +20,7 @@ func (s *StructArrayField) Clone() *StructArrayField {
 		Name:        s.Name,
 		Description: s.Description,
 		Fields:      CloneFields(s.Fields),
+		TypeParams:  common.CloneKeyValuePairs(s.TypeParams),
 	}
 }
 
@@ -29,10 +33,12 @@ func CloneStructArrayFields(structArrayFields []*StructArrayField) []*StructArra
 }
 
 func (s *StructArrayField) Equal(other StructArrayField) bool {
+	var paramsA common.KeyValuePairs = s.TypeParams
 	return s.FieldID == other.FieldID &&
 		s.Name == other.Name &&
 		s.Description == other.Description &&
-		CheckFieldsEqual(s.Fields, other.Fields)
+		CheckFieldsEqual(s.Fields, other.Fields) &&
+		paramsA.Equal(other.TypeParams)
 }
 
 func CheckStructArrayFieldsEqual(structArrayFieldsA, structArrayFieldsB []*StructArrayField) bool {
@@ -63,6 +69,7 @@ func MarshalStructArrayFieldModel(structArrayField *StructArrayField) *schemapb.
 		Name:        structArrayField.Name,
 		Description: structArrayField.Description,
 		Fields:      MarshalFieldModels(structArrayField.Fields),
+		TypeParams:  structArrayField.TypeParams,
 	}
 }
 
@@ -88,6 +95,7 @@ func UnmarshalStructArrayFieldModel(fieldSchema *schemapb.StructArrayFieldSchema
 		Name:        fieldSchema.Name,
 		Description: fieldSchema.Description,
 		Fields:      UnmarshalFieldModels(fieldSchema.Fields),
+		TypeParams:  fieldSchema.TypeParams,
 	}
 }
 

internal/querycoordv2/task/utils.go

@@ -285,9 +285,35 @@ func applyCollectionMmapSetting(schema *schemapb.CollectionSchema,
 		}
 	}
 	for _, structField := range schema.GetStructArrayFields() {
+		structTypeParams := structField.GetTypeParams()
+		structMmapEnabled, structExist := common.IsMmapDataEnabled(structTypeParams...)
+
+		// If struct field itself doesn't have mmap setting, inherit from collection
+		if !structExist && exist &&
+			!common.FieldHasMmapKey(schema, structField.GetFieldID()) {
+			structField.TypeParams = append(structField.TypeParams, &commonpb.KeyValuePair{
+				Key:   common.MmapEnabledKey,
+				Value: strconv.FormatBool(collectionMmapEnabled),
+			})
+			// Update struct's mmap state since we just set it
+			structMmapEnabled = collectionMmapEnabled
+			structExist = true
+		}
+
+		// Apply mmap setting to fields inside struct
 		for _, field := range structField.GetFields() {
-			if exist &&
+			// Skip if field already has mmap setting
-				!common.FieldHasMmapKey(schema, field.GetFieldID()) {
+			if common.FieldHasMmapKey(schema, field.GetFieldID()) {
+				continue
+			}
+
+			// Priority: struct field setting > collection setting
+			if structExist {
+				field.TypeParams = append(field.TypeParams, &commonpb.KeyValuePair{
+					Key:   common.MmapEnabledKey,
+					Value: strconv.FormatBool(structMmapEnabled),
+				})
+			} else if exist {
 				field.TypeParams = append(field.TypeParams, &commonpb.KeyValuePair{
 					Key:   common.MmapEnabledKey,
 					Value: strconv.FormatBool(collectionMmapEnabled),

internal/rootcoord/alter_collection_task.go

@@ -91,13 +91,14 @@ func ResetFieldProperties(coll *model.Collection, fieldName string, newProps []*
 			return nil
 		}
 	}
-	for _, structField := range coll.StructArrayFields {
+	for i, structField := range coll.StructArrayFields {
 		if structField.Name == fieldName {
-			return merr.WrapErrParameterInvalidMsg("struct field has no properties to alter", fieldName)
+			coll.StructArrayFields[i].TypeParams = newProps
+			return nil
 		}
-		for i, field := range structField.Fields {
+		for j, field := range structField.Fields {
 			if field.Name == fieldName {
-				structField.Fields[i].TypeParams = newProps
+				coll.StructArrayFields[i].Fields[j].TypeParams = newProps
 				return nil
 			}
 		}
@@ -113,7 +114,7 @@ func GetFieldProperties(coll *model.Collection, fieldName string) ([]*commonpb.K
 	}
 	for _, structField := range coll.StructArrayFields {
 		if structField.Name == fieldName {
-			return nil, merr.WrapErrParameterInvalidMsg("struct field has no properties", fieldName)
+			return structField.TypeParams, nil
 		}
 		for _, field := range structField.Fields {
 			if field.Name == fieldName {

pkg/common/common.go

@@ -316,6 +316,28 @@ func FieldHasMmapKey(schema *schemapb.CollectionSchema, fieldID int64) bool {
 			return false
 		}
 	}
+	// Check struct array fields
+	for _, structField := range schema.GetStructArrayFields() {
+		if structField.GetFieldID() == fieldID {
+			for _, kv := range structField.GetTypeParams() {
+				if kv.Key == MmapEnabledKey {
+					return true
+				}
+			}
+			return false
+		}
+		// Check fields inside struct
+		for _, field := range structField.GetFields() {
+			if field.GetFieldID() == fieldID {
+				for _, kv := range field.GetTypeParams() {
+					if kv.Key == MmapEnabledKey {
+						return true
+					}
+				}
+				return false
+			}
+		}
+	}
 	return false
 }