fix: return collection on recovering but not collection not loaded when target is not recovered (#32447)

issue: #32398

Signed-off-by: chyezh <chyezh@outlook.com>

internal/querycoordv2/services.go

@@ -913,9 +913,9 @@ func (s *Server) GetShardLeaders(ctx context.Context, req *querypb.GetShardLeade
 
 	channels := s.targetMgr.GetDmChannelsByCollection(req.GetCollectionID(), meta.CurrentTarget)
 	if len(channels) == 0 {
-		msg := "failed to get channels"
-		err := merr.WrapErrCollectionNotLoaded(req.GetCollectionID())
-		log.Warn(msg, zap.Error(err))
+		err := merr.WrapErrCollectionOnRecovering(req.GetCollectionID(),
+			"loaded collection do not found any channel in target, may be in recovery")
+		log.Warn("failed to get channels", zap.Error(err))
 		resp.Status = merr.Status(err)
 		return resp, nil
 	}

pkg/util/merr/errors.go

@@ -51,6 +51,7 @@ var (
 	ErrCollectionNotFullyLoaded   = newMilvusError("collection not fully loaded", 103, true)
 	ErrCollectionLoaded           = newMilvusError("collection already loaded", 104, false)
 	ErrCollectionIllegalSchema    = newMilvusError("illegal collection schema", 105, false)
+	ErrCollectionOnRecovering     = newMilvusError("collection on recovering", 106, true)
 
 	// Partition related
 	ErrPartitionNotFound       = newMilvusError("partition not found", 200, false)

pkg/util/merr/errors_test.go

@@ -86,6 +86,7 @@ func (s *ErrSuite) TestWrap() {
 	s.ErrorIs(WrapErrCollectionNotLoaded("test_collection", "failed to query"), ErrCollectionNotLoaded)
 	s.ErrorIs(WrapErrCollectionNotFullyLoaded("test_collection", "failed to query"), ErrCollectionNotFullyLoaded)
 	s.ErrorIs(WrapErrCollectionNotLoaded("test_collection", "failed to alter index %s", "hnsw"), ErrCollectionNotLoaded)
+	s.ErrorIs(WrapErrCollectionOnRecovering("test_collection", "channel lost %s", "dev"), ErrCollectionOnRecovering)
 
 	// Partition related
 	s.ErrorIs(WrapErrPartitionNotFound("test_partition", "failed to get partition"), ErrPartitionNotFound)

pkg/util/merr/utils.go

@@ -479,6 +479,16 @@ func WrapErrCollectionIllegalSchema(collection string, msgAndArgs ...any) error
 	return err
 }
 
+// WrapErrCollectionOnRecovering wraps ErrCollectionOnRecovering with collection
+func WrapErrCollectionOnRecovering(collection any, msgAndArgs ...any) error {
+	err := wrapFields(ErrCollectionOnRecovering, value("collection", collection))
+	if len(msgAndArgs) > 0 {
+		msg := msgAndArgs[0].(string)
+		err = errors.Wrapf(err, msg, msgAndArgs[1:]...)
+	}
+	return err
+}
+
 func WrapErrAliasNotFound(db any, alias any, msg ...string) error {
 	err := wrapFields(ErrAliasNotFound,
 		value("database", db),