diff --git a/rel/files/emqttd.config b/rel/files/emqttd.config
index b4681e448..ff30db38d 100644
--- a/rel/files/emqttd.config
+++ b/rel/files/emqttd.config
@@ -89,7 +89,7 @@
         {session, [
             %% Max number of QoS 1 and 2 messages that can be “in flight” at one time.
             %% 0 means no limit
-            {max_inflight, 100},
+            {max_inflight, 20},
 
             %% Max retries for unack Qos1/2 messages
             {unack_retries, 3},
@@ -114,7 +114,7 @@
         {queue, [
             %% Max queue length. enqueued messages when persistent client disconnected, 
             %% or inflight window is full.
-            {max_length, 1000},
+            {max_length, 100},
 
             %% Low-water mark of queued messsages
             {low_watermark, 0.2},