diff --git a/db/db_test.cc b/db/db_test.cc
index 1d2789de2..aca07bcff 100644
--- a/db/db_test.cc
+++ b/db/db_test.cc
@@ -9,6 +9,7 @@
 
 #include <algorithm>
 #include <set>
+#include <unistd.h>
 
 #include "rocksdb/db.h"
 #include "rocksdb/filter_policy.h"