Fix re-resolution in pick_first

1 files changed, 7 insertions, 7 deletions

diff --git a/src/core/ext/filters/client_channel/subchannel.cc b/src/core/ext/filters/client_channel/subchannel.cc
index 93df2aff70..71ef8c518b 100644
--- a/src/core/ext/filters/client_channel/subchannel.cc
+++ b/src/core/ext/filters/client_channel/subchannel.cc
@@ -402,8 +402,6 @@ static void continue_connect_locked(grpc_subchannel* c) {
   c->next_attempt_deadline = c->backoff->NextAttemptTime();
   args.deadline = std::max(c->next_attempt_deadline, min_deadline);
   args.channel_args = c->args;
-  grpc_connectivity_state_set(&c->state_tracker, GRPC_CHANNEL_CONNECTING,
-                              GRPC_ERROR_NONE, "state_change");
   grpc_connector_connect(c->connector, &args, &c->connecting_result,
                          &c->on_connected);
 }
@@ -459,27 +457,24 @@ static void maybe_start_connecting_locked(grpc_subchannel* c) {
     /* Don't try to connect if we're already disconnected */
     return;
   }
-
   if (c->connecting) {
     /* Already connecting: don't restart */
     return;
   }
-
   if (c->connected_subchannel != nullptr) {
     /* Already connected: don't restart */
     return;
   }
-
   if (!grpc_connectivity_state_has_watchers(&c->state_tracker)) {
     /* Nobody is interested in connecting: so don't just yet */
     return;
   }
-
   c->connecting = true;
   GRPC_SUBCHANNEL_WEAK_REF(c, "connecting");
-
   if (!c->backoff_begun) {
     c->backoff_begun = true;
+    grpc_connectivity_state_set(&c->state_tracker, GRPC_CHANNEL_CONNECTING,
+                                GRPC_ERROR_NONE, "connecting");
     continue_connect_locked(c);
   } else {
     GPR_ASSERT(!c->have_alarm);
@@ -494,6 +489,11 @@ static void maybe_start_connecting_locked(grpc_subchannel* c) {
     }
     GRPC_CLOSURE_INIT(&c->on_alarm, on_alarm, c, grpc_schedule_on_exec_ctx);
     grpc_timer_init(&c->alarm, c->next_attempt_deadline, &c->on_alarm);
+    // During backoff, we prefer the connectivity state of CONNECTING instead of
+    // TRANSIENT_FAILURE in order to prevent triggering re-resolution
+    // continuously in pick_first.
+    grpc_connectivity_state_set(&c->state_tracker, GRPC_CHANNEL_CONNECTING,
+                                GRPC_ERROR_NONE, "backoff");
   }
 }