datasources: querier: log empty refids (#107111)

* datasources: querier: log empty refids

* improved logging

pkg/registry/apis/query/query.go

@@ -179,6 +179,8 @@ func (r *queryREST) Connect(connectCtx context.Context, name string, _ runtime.O
 			return
 		}
 
+		logEmptyRefids(raw.Queries, b.log)
+
 		for i := range req.Requests {
 			req.Requests[i].Headers = ExtractKnownHeaders(httpreq.Header)
 		}
@@ -215,6 +217,20 @@ func (r *queryREST) Connect(connectCtx context.Context, name string, _ runtime.O
 	}), nil
 }
 
+func logEmptyRefids(queries []v0alpha1.DataQuery, logger log.Logger) {
+	emptyCount := 0
+
+	for _, q := range queries {
+		if q.RefID == "" {
+			emptyCount += 1
+		}
+	}
+
+	if emptyCount > 0 {
+		logger.Info("empty refid found", "empty_count", emptyCount, "query_count", len(queries))
+	}
+}
+
 func (b *QueryAPIBuilder) execute(ctx context.Context, req parsedRequestInfo, instanceConfig clientapi.InstanceConfigurationSettings) (qdr *backend.QueryDataResponse, err error) {
 	switch len(req.Requests) {
 	case 0: