diff --git a/core/plug-in/stats/query_stats.cxx b/core/plug-in/stats/query_stats.cxx
index f226be5c..6bb1444c 100644
--- a/core/plug-in/stats/query_stats.cxx
+++ b/core/plug-in/stats/query_stats.cxx
@@ -7,6 +7,7 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 #include <map>
 #include <string>