MDEV-16957: Server crashes in Field_iterator_natural_join::next upon 2nd execution of SP

The problem was that join_columns creation was not finished due to error of notfound column in USING, but next execution tried to use join_columns lists.

Solution is cleanup the lists on error. It can eat memory in statement MEM_ROOT but it is an error and error will be fixed or statement/procedure removed/altered.

2 files changed, 23 insertions, 1 deletions

diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 8ffb7bc118b..272aa11977d 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -7764,10 +7764,22 @@ store_natural_using_join_columns(THD *thd, TABLE_LIST *natural_using_join,
 
   result= FALSE;
 
-err:
   if (arena)
     thd->restore_active_arena(arena, &backup);
   DBUG_RETURN(result);
+
+err:
+  /*
+     Actually we failed to build join columns list, so we have to
+     clear it to avoid problems with half-build join on next run.
+     The list was created in mark_common_columns().
+   */
+  table_ref_1->remove_join_columns();
+  table_ref_2->remove_join_columns();
+
+  if (arena)
+    thd->restore_active_arena(arena, &backup);
+  DBUG_RETURN(TRUE);
 }
 
 
diff --git a/sql/table.h b/sql/table.h
index 1d4a1d9a2d2..4725eb96432 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -2184,6 +2184,16 @@ struct TABLE_LIST
   } 
   void set_lock_type(THD* thd, enum thr_lock_type lock);
 
+  void remove_join_columns()
+  {
+    if (join_columns)
+    {
+      join_columns->empty();
+      join_columns= NULL;
+      is_join_columns_complete= FALSE;
+    }
+  }
+
 private:
   bool prep_check_option(THD *thd, uint8 check_opt_type);
   bool prep_where(THD *thd, Item **conds, bool no_where_clause);