diff --git a/etc/emqx.conf b/etc/emqx.conf
index 1d623953b..df50884e9 100644
--- a/etc/emqx.conf
+++ b/etc/emqx.conf
@@ -371,8 +371,8 @@ log.file = emqx.log
 ## Limits the total number of characters printed for each log event.
 ##
 ## Value: Integer
-## Default: 1024
-log.chars_limit = 1024
+## Default: 8192
+log.chars_limit = 8192
 
 ## Maximum size of each log file.
 ##
@@ -550,6 +550,18 @@ zone.external.acl_deny_action = ignore
 ## Numbers delimited by `|'. Zero or negative is to disable.
 zone.external.force_gc_policy = 1000|1MB
 
+## Max message queue length and total heap size to force shutdown
+## connection/session process.
+## Message queue here is the Erlang process mailbox, but not the number
+## of queued MQTT messages of QoS 1 and 2.
+##
+## Numbers delimited by `|'. Zero or negative is to disable.
+##
+## Default:
+##   - 8000|800MB on ARCH_64 system
+##   - 1000|100MB on ARCH_32 sytem
+## zone.external.force_shutdown_policy = 8000|800MB
+
 ## Maximum MQTT packet size allowed.
 ##
 ## Value: Bytes
@@ -2210,19 +2222,43 @@ broker.route_batch_clean = off
 ## System Monitor
 ##--------------------------------------------------------------------
 
-## Enable Long GC monitoring.
+## Enable Long GC monitoring. Disable if the value is 0.
 ## Notice: don't enable the monitor in production for:
 ## https://github.com/erlang/otp/blob/feb45017da36be78d4c5784d758ede619fa7bfd3/erts/emulator/beam/erl_gc.c#L421
 ##
-## Value: true | false
-sysmon.long_gc = false
+## Value: Duration
+##  - h: hour
+##  - m: minute
+##  - s: second
+##  - ms: milliseconds
+##
+## Examples:
+##  - 2h:  2 hours
+##  - 30m: 30 minutes
+##  - 0.1s: 0.1 seconds
+##  - 100ms : 100 milliseconds
+##
+## Default: 0ms
+sysmon.long_gc = 0
 
 ## Enable Long Schedule(ms) monitoring.
 ##
 ## See: http://erlang.org/doc/man/erlang.html#system_monitor-2
 ##
-## Value: Number
-sysmon.long_schedule = 240
+## Value: Duration
+##  - h: hour
+##  - m: minute
+##  - s: second
+##  - ms: milliseconds
+##
+## Examples:
+##  - 2h:  2 hours
+##  - 30m: 30 minutes
+##  - 0.1s: 0.1 seconds
+##  - 100ms: 100 milliseconds
+##
+## Default: 0ms
+sysmon.long_schedule = 240ms
 
 ## Enable Large Heap monitoring.
 ##
diff --git a/priv/emqx.schema b/priv/emqx.schema
index 5c7f421ce..804ab041d 100644
--- a/priv/emqx.schema
+++ b/priv/emqx.schema
@@ -400,7 +400,7 @@ end}.
   {datatype, {enum, [debug, info, notice, warning, error, critical, alert, emergency, all]}}
 ]}.
 
-{mapping, "log.primary_level", "emqx.primary_log_level", [
+{mapping, "log.primary_level", "kernel.primary_log_level", [
    {default, error},
    {datatype, {enum, [debug, info, notice, warning, error, critical, alert, emergency, all]}}
 ]}.
@@ -420,8 +420,8 @@ end}.
   {datatype, file}
 ]}.
 
-{mapping, "log.chars_limit", "log.chars_limit", [
-  {default, 1024},
+{mapping, "log.chars_limit", "kernel.logger", [
+  {default, 8192},
   {datatype, integer}
 ]}.
 
@@ -462,10 +462,6 @@ end}.
   hidden
 ]}.
 
-{translation, "emqx.primary_log_level", fun(Conf) ->
-    cuttlefish:conf_get("log.level", Conf)
-end}.
-
 {translation, "kernel.logger", fun(Conf) ->
     LogTo = cuttlefish:conf_get("log.to", Conf),
     LogLevel = cuttlefish:conf_get("log.level", Conf),
@@ -854,7 +850,7 @@ end}.
 %% of queued MQTT messages of QoS 1 and 2.
 %% Zero or negative is to disable.
 {mapping, "zone.$name.force_shutdown_policy", "emqx.zones", [
-  {default, "0 | 0MB"},
+  {default, "default"},
   {datatype, string}
 ]}.
 
@@ -903,15 +899,34 @@ end}.
                                          count => list_to_integer(Count)}
                                end,
                     {force_gc_policy, GcPolicy};
+               ("force_shutdown_policy", "default") ->
+                    {DefaultLen, DefaultSize} =
+                        case erlang:system_info(wordsize) of
+                            8 -> % arch_64
+                              {8000, cuttlefish_bytesize:parse("800MB")};
+                            4 -> % arch_32
+                              {1000, cuttlefish_bytesize:parse("100MB")}
+                        end,
+                    {force_shutdown_policy, #{message_queue_len => DefaultLen,
+                                              max_heap_size => DefaultSize}};
                ("force_shutdown_policy", Val) ->
                     [Len, Siz] = string:tokens(Val, "| "),
-                    ShutdownPolicy = case cuttlefish_bytesize:parse(Siz) of
-                                         {error, Reason} ->
-                                             error(Reason);
-                                         Siz1 ->
-                                             #{message_queue_len => list_to_integer(Len),
-                                               max_heap_size => Siz1}
-                                     end,
+                    MaxSiz = case erlang:system_info(wordsize) of
+                                8 -> % arch_64
+                                  (1 bsl 59) - 1;
+                                4 -> % arch_32
+                                  (1 bsl 27) - 1
+                             end,
+                    ShutdownPolicy =
+                      case cuttlefish_bytesize:parse(Siz) of
+                          {error, Reason} ->
+                              error(Reason);
+                          Siz1 when Siz1 > MaxSiz ->
+                              cuttlefish:invalid(io_lib:format("force_shutdown_policy: heap-size ~s is too large", [Siz]));
+                          Siz1 ->
+                              #{message_queue_len => list_to_integer(Len),
+                                max_heap_size => Siz1}
+                      end,
                     {force_shutdown_policy, ShutdownPolicy};
                ("mqueue_priorities", Val) ->
                     case Val of
@@ -2059,14 +2074,14 @@ end}.
 %% @doc Long GC, don't monitor in production mode for:
 %% https://github.com/erlang/otp/blob/feb45017da36be78d4c5784d758ede619fa7bfd3/erts/emulator/beam/erl_gc.c#L421
 {mapping, "sysmon.long_gc", "emqx.sysmon", [
-  {default, false},
-  {datatype, {enum, [true, false]}}
+  {default, 0},
+  {datatype, [integer, {duration, ms}]}
 ]}.
 
 %% @doc Long Schedule(ms)
 {mapping, "sysmon.long_schedule", "emqx.sysmon", [
-  {default, 1000},
-  {datatype, integer}
+  {default, 240},
+  {datatype, [integer, {duration, ms}]}
 ]}.
 
 %% @doc Large Heap
diff --git a/src/emqx_app.erl b/src/emqx_app.erl
index 2ef660521..bc9d58408 100644
--- a/src/emqx_app.erl
+++ b/src/emqx_app.erl
@@ -31,7 +31,7 @@ start(_Type, _Args) ->
     %%   kernel config `logger_level` before starting the erlang vm.
     %% This is because the latter approach an annoying debug msg will be printed out:
     %%   "[debug] got_unexpected_message {'EXIT',<0.1198.0>,normal}"
-    logger:set_primary_config(level, application:get_env(emqx, primary_log_level, error)),
+    logger:set_primary_config(level, application:get_env(kernel, primary_log_level, error)),
 
     print_banner(),
     ekka:start(),
diff --git a/src/emqx_stats.erl b/src/emqx_stats.erl
index bec56f142..771069704 100644
--- a/src/emqx_stats.erl
+++ b/src/emqx_stats.erl
@@ -73,6 +73,8 @@
 -define(PUBSUB_STATS, [
     'topics/count',
     'topics/max',
+    'suboptions/count',
+    'suboptions/max',
     'subscribers/count',
     'subscribers/max',
     'subscriptions/count',
@@ -242,9 +244,12 @@ code_change(_OldVsn, State, _Extra) ->
 %%------------------------------------------------------------------------------
 
 safe_update_element(Key, Val) ->
-    try ets:update_element(?TAB, Key, {2, Val})
+    try ets:update_element(?TAB, Key, {2, Val}) of
+        false ->
+            ets:insert_new(?TAB, {Key, Val});
+        true ->
+            true
     catch
         error:badarg ->
-            ets:insert_new(?TAB, {Key, Val})
+            ?LOG(warning, "[Stats] Update ~p to ~p failed", [Key, Val])
     end.
-
diff --git a/src/emqx_sys_mon.erl b/src/emqx_sys_mon.erl
index 03cc95819..b75503b53 100644
--- a/src/emqx_sys_mon.erl
+++ b/src/emqx_sys_mon.erl
@@ -33,9 +33,9 @@
         , code_change/3
         ]).
 
--type(option() :: {long_gc, false | pos_integer()}
-                | {long_schedule, false | pos_integer()}
-                | {large_heap, pos_integer()}
+-type(option() :: {long_gc, non_neg_integer()}
+                | {long_schedule, non_neg_integer()}
+                | {large_heap, non_neg_integer()}
                 | {busy_port, boolean()}
                 | {busy_dist_port, boolean()}).
 
@@ -66,11 +66,11 @@ parse_opt(Opts) ->
     parse_opt(Opts, []).
 parse_opt([], Acc) ->
     Acc;
-parse_opt([{long_gc, false}|Opts], Acc) ->
+parse_opt([{long_gc, 0}|Opts], Acc) ->
     parse_opt(Opts, Acc);
 parse_opt([{long_gc, Ms}|Opts], Acc) when is_integer(Ms) ->
     parse_opt(Opts, [{long_gc, Ms}|Acc]);
-parse_opt([{long_schedule, false}|Opts], Acc) ->
+parse_opt([{long_schedule, 0}|Opts], Acc) ->
     parse_opt(Opts, Acc);
 parse_opt([{long_schedule, Ms}|Opts], Acc) when is_integer(Ms) ->
     parse_opt(Opts, [{long_schedule, Ms}|Acc]);
@@ -177,4 +177,3 @@ safe_publish(Event, WarnMsg) ->
 sysmon_msg(Topic, Payload) ->
     Msg = emqx_message:make(?SYSMON, Topic, Payload),
     emqx_message:set_flag(sys, Msg).
-
diff --git a/src/emqx_ws_connection.erl b/src/emqx_ws_connection.erl
index 44e1eb681..e828dd0a2 100644
--- a/src/emqx_ws_connection.erl
+++ b/src/emqx_ws_connection.erl
@@ -160,6 +160,7 @@ websocket_init(#state{request = Req, options = Options}) ->
     EnableStats = emqx_zone:get_env(Zone, enable_stats, true),
     IdleTimout = emqx_zone:get_env(Zone, idle_timeout, 30000),
     emqx_logger:set_metadata_peername(esockd_net:format(Peername)),
+    ok = emqx_misc:init_proc_mng_policy(Zone),
     {ok, #state{peername     = Peername,
                 sockname     = Sockname,
                 parse_state  = ParserState,