diff --git a/server/core/routingworker.cc b/server/core/routingworker.cc
index bbc5b88cc..fcad1f07c 100644
--- a/server/core/routingworker.cc
+++ b/server/core/routingworker.cc
@@ -1064,7 +1064,7 @@ std::unique_ptr<json_t> RoutingWorker::get_qc_stats_as_json(const char* zHost)
 // static
 RoutingWorker* RoutingWorker::pick_worker()
 {
-    static int id_generator = 0;
+    static uint32_t id_generator = 0;
     int id = this_unit.id_min_worker
         + (mxb::atomic::add(&id_generator, 1, mxb::atomic::RELAXED) % this_unit.nWorkers);
     return get(id);