diff --git a/Makefile b/Makefile
index abd416178..5841ef611 100644
--- a/Makefile
+++ b/Makefile
@@ -14,6 +14,7 @@ dep_pbkdf2       = git https://github.com/emqtt/pbkdf2 2.0.1
 dep_lager_syslog = git https://github.com/basho/lager_syslog
 dep_bcrypt       = git https://github.com/smarkets/erlang-bcrypt master
 
+ERLC_OPTS += +debug_info
 ERLC_OPTS += +'{parse_transform, lager_transform}'
 
 NO_AUTOPATCH = cuttlefish
diff --git a/etc/emq.conf b/etc/emq.conf
index ea7e3e2ba..e0a0508d3 100644
--- a/etc/emq.conf
+++ b/etc/emq.conf
@@ -191,7 +191,7 @@ mqtt.mqueue.type = simple
 
 ## Max queue length. Enqueued messages when persistent client disconnected,
 ## or inflight window is full. 0 means no limit.
-mqtt.mqueue.max_length = 0
+mqtt.mqueue.max_length = 1000
 
 ## Low-water mark of queued messages
 mqtt.mqueue.low_watermark = 20%