fix: [2.4] fill the metric type field in the LoadMetaInfo object (milvus-io#35963)

- issue: milvus-io#35960
- pr: milvus-io#35962

Signed-off-by: SimFG <[email protected]>

Author: SimFG

internal/core/src/query/SearchOnSealed.cpp

@@ -42,7 +42,8 @@ SearchOnSealedIndex(const Schema& schema,
     // Keep the field_indexing smart pointer, until all reference by raw dropped.
     auto field_indexing = record.get_field_indexing(field_id);
     AssertInfo(field_indexing->metric_type_ == search_info.metric_type_,
-               "Metric type of field index isn't the same with search info");
+               "Metric type of field index isn't the same with search info,"
+               "field index: {}, search info: {}", field_indexing->metric_type_, search_info.metric_type_);
 
     auto dataset = knowhere::GenDataSet(num_queries, dim, query_data);
     dataset->SetIsSparse(is_sparse);

internal/core/src/segcore/ConcurrentVector.h

@@ -71,7 +71,7 @@ class ThreadSafeVector {
 
     int64_t
     size() const {
-        std::lock_guard lck(mutex_);
+        std::shared_lock lck(mutex_);
         return size_;
     }
 

internal/querycoordv2/task/executor.go

@@ -35,6 +35,7 @@ import (
 	. "github.com/milvus-io/milvus/internal/querycoordv2/params"
 	"github.com/milvus-io/milvus/internal/querycoordv2/session"
 	"github.com/milvus-io/milvus/internal/querycoordv2/utils"
+	"github.com/milvus-io/milvus/pkg/common"
 	"github.com/milvus-io/milvus/pkg/log"
 	"github.com/milvus-io/milvus/pkg/util/commonpbutil"
 	"github.com/milvus-io/milvus/pkg/util/funcutil"
@@ -197,6 +198,8 @@ func (ex *Executor) loadSegment(task *SegmentTask, step int) error {
 		return err
 	}
 
+	ex.setMetricTypeForMetaInfo(loadMeta, indexInfos)
+
 	req := packLoadSegmentRequest(
 		task,
 		action,
@@ -550,6 +553,8 @@ func (ex *Executor) setDistribution(task *LeaderTask, step int) error {
 		return err
 	}
 
+	ex.setMetricTypeForMetaInfo(loadMeta, indexInfo)
+
 	req := &querypb.SyncDistributionRequest{
 		Base: commonpbutil.NewMsgBase(
 			commonpbutil.WithMsgType(commonpb.MsgType_LoadSegments),
@@ -722,3 +727,15 @@ func (ex *Executor) getLoadInfo(ctx context.Context, collectionID, segmentID int
 	loadInfo := utils.PackSegmentLoadInfo(segment, channel.GetSeekPosition(), indexes)
 	return loadInfo, indexInfos, nil
 }
+
+// setMetricTypeForMetaInfo it's a compatibility method for rolling upgrade from 2.3.x to 2.4
+func (ex *Executor) setMetricTypeForMetaInfo(metaInfo *querypb.LoadMetaInfo, indexInfos []*indexpb.IndexInfo) {
+	for _, info := range indexInfos {
+		for _, param := range info.IndexParams {
+			if param.GetKey() == common.MetricTypeKey {
+				metaInfo.MetricType = param.GetValue()
+				return
+			}
+		}
+	}
+}