add wrr lb fallback strategy (#2441)

Co-authored-by: jiangyuting <jiangyutingwangyi@163.com>
apache · Nov 27, 2023 · 3da0a66 · 3da0a66
1 parent 713bbb1
commit 3da0a66
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/src/brpc/policy/weighted_round_robin_load_balancer.cpp b/src/brpc/policy/weighted_round_robin_load_balancer.cpp
@@ -185,7 +185,8 @@ int WeightedRoundRobinLoadBalancer::SelectServer(const SelectIn& in, SelectOut*
     size_t remain_servers = s->server_list.size();
     while (remain_servers > 0) {
         SocketId server_id = GetServerInNextStride(s->server_list, filter, tls_temp);
-        if (!ExcludedServers::IsExcluded(in.excluded, server_id)
+        if ((remain_servers == 1 // always take last chance
+                || !ExcludedServers::IsExcluded(in.excluded, server_id))
             && Socket::Address(server_id, out->ptr) == 0
             && (*out->ptr)->IsAvailable()) {
             // update tls.