ARROW-9168: [C++][Flight] Don't share TCP connection among clients

cyb70289 · pitrou · commit d08af2f8b7db · 2020-06-18T17:23:31.000+02:00
Flight benchmark performs worse when working threads increases. It can be improved by setting gRPC option GRPC_ARG_USE_LOCAL_SUBCHANNEL_POOL to make each client creating its own TCP connection to server, without sharing one connection. Closes apache#7476 from cyb70289/flight Authored-by: Yibo Cai <cyb70289@gmail.com> Signed-off-by: Antoine Pitrou <antoine@python.org>
diff --git a/cpp/src/arrow/flight/client.cc b/cpp/src/arrow/flight/client.cc
@@ -858,6 +858,9 @@ class FlightClient::FlightClientImpl {
     args.SetInt(GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS, 100);
     // Receive messages of any size
     args.SetMaxReceiveMessageSize(-1);
+    // Setting this arg enables each client to open it's own TCP connection to server,
+    // not sharing one single connection, which becomes bottleneck under high load.
+    args.SetInt(GRPC_ARG_USE_LOCAL_SUBCHANNEL_POOL, 1);
 
     if (options.override_hostname != "") {
       args.SetSslTargetNameOverride(options.override_hostname);
