diff --git a/idl/duplication.thrift b/idl/duplication.thrift
index 91aefd2781..589cc5d085 100644
--- a/idl/duplication.thrift
+++ b/idl/duplication.thrift
@@ -173,7 +173,8 @@ struct duplication_confirm_entry
     2:i64       confirmed_decree;
     3:optional bool checkpoint_prepared = false;
 
-    //
+    // Last committed decree from the primary replica of each partition, collected by
+    // meta server and used to be compared with duplicating progress of follower table.
     4:optional i64 last_committed_decree;
 }
 
diff --git a/src/meta/duplication/duplication_info.h b/src/meta/duplication/duplication_info.h
index d1503a8682..7563d3d411 100644
--- a/src/meta/duplication/duplication_info.h
+++ b/src/meta/duplication/duplication_info.h
@@ -218,7 +218,7 @@ class duplication_info
 
     struct partition_progress
     {
-        // last committed decree collected from the primary replica of each partition.
+        // Last committed decree collected from the primary replica of each partition.
         // Not persisted to remote meta storage.
         int64_t last_committed_decree{invalid_decree};
 
diff --git a/src/meta/server_state.cpp b/src/meta/server_state.cpp
index 6a352473f1..8e68113f72 100644
--- a/src/meta/server_state.cpp
+++ b/src/meta/server_state.cpp
@@ -1163,7 +1163,7 @@ void server_state::create_app(dsn::message_ex *msg)
     zauto_write_lock l(_lock);
 
     auto app = get_app(request.app_name);
-    if (!app) {
+    if (app) {
         configuration_create_app_response response;
 
         switch (app->status) {