diff --git a/sql/sql_select.h b/sql/sql_select.h
index fe6a640003f..a953354abb0 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -1265,7 +1265,7 @@ public:
 
 #ifndef DBUG_OFF
   void dbug_verify_sj_inner_tables(uint n_positions) const;
-  uint dbug_join_tab_array_size;
+  int dbug_join_tab_array_size;
 #endif
 
   /* We also maintain a stack of join optimization states in * join->positions[] */