diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 90eb8c06660..c7f9de2ef6d 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -2408,6 +2408,7 @@ add_ft_keys(DYNAMIC_ARRAY *keyuse_array,
   keyuse.keypart= FT_KEYPART;
   keyuse.used_tables=cond_func->key_item()->used_tables();
   keyuse.optimize= 0;
+  keyuse.keypart_map= 0;
   VOID(insert_dynamic(keyuse_array,(gptr) &keyuse));
 }