Reduce default tcp client nums to schedulers/2

etc/emqx.conf

@@ -327,10 +327,11 @@ rpc.tcp_server_port = 5369
 ## Value: Port [1024-65535]
 rpc.tcp_client_port = 5369
 
-## Number of utgoing RPC connections.
+## Number of Outgoing RPC connections.
 ##
 ## Value: Interger [1-256]
-rpc.tcp_client_num = 32
+## Defaults to NumberOfCPUSchedulers / 2
+#rpc.tcp_client_num = 1
 
 ## RCP Client connect timeout.
 ##

priv/emqx.schema

@@ -362,11 +362,18 @@ end}.
 
 %% Default TCP port for outgoing connections
 {mapping, "rpc.tcp_client_num", "gen_rpc.tcp_client_num", [
-  {default, 32},
+  {default, 0},
   {datatype, integer},
   {validators, ["range:gt_0_lt_256"]}
 ]}.
 
+{translation, "gen_rpc.tcp_client_num", fun(Conf) ->
+  case cuttlefish:conf_get("rpc.tcp_client_num", Conf) of
+    0 -> max(1, erlang:system_info(schedulers) div 2);
+    V -> V
+  end
+end}.
+
 %% Client connect timeout
 {mapping, "rpc.connect_timeout", "gen_rpc.connect_timeout", [
   {default, "5s"},
@@ -428,7 +435,7 @@ end}.
 ]}.
 
 {validator, "range:gt_0_lt_256", "must greater than 0 and less than 256",
-  fun(X) -> X > 0 andalso X < 256 end
+  fun(X) -> X >= 0 andalso X < 256 end
 }.
 
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