MDEV-14517 Cleanup for Item::with_subselect and Item::has_subquery()

sql/filesort.cc

@@ -830,11 +830,11 @@ static ha_rows find_all_keys(THD *thd, Sort_param *param, SQL_SELECT *select,
         MY_BITMAP *tmp_write_set= sort_form->write_set;
         MY_BITMAP *tmp_vcol_set= sort_form->vcol_set;
 
-        if (select->cond->with_subselect)
+        if (select->cond->with_subquery())
           sort_form->column_bitmaps_set(save_read_set, save_write_set,
                                         save_vcol_set);
         write_record= (select->skip_record(thd) > 0);
-        if (select->cond->with_subselect)
+        if (select->cond->with_subquery())
           sort_form->column_bitmaps_set(tmp_read_set,
                                         tmp_write_set,
                                         tmp_vcol_set);

sql/item.cc

@@ -532,7 +532,6 @@ Item::Item(THD *thd):
   marker= 0;
   maybe_null=null_value=with_sum_func=with_window_func=with_field=0;
   in_rollup= 0;
-  with_subselect= 0;
    /* Initially this item is not attached to any JOIN_TAB. */
   join_tab_idx= MAX_TABLES;
 
@@ -577,8 +576,7 @@ Item::Item(THD *thd, Item *item):
   with_window_func(item->with_window_func),
   with_field(item->with_field),
   fixed(item->fixed),
-  is_autogenerated_name(item->is_autogenerated_name),
-  with_subselect(item->has_subquery())
+  is_autogenerated_name(item->is_autogenerated_name)
 {
   next= thd->free_list;				// Put in free list
   thd->free_list= this;
@@ -8194,7 +8192,7 @@ Item_cache_wrapper::Item_cache_wrapper(THD *thd, Item *item_arg):
   with_sum_func= orig_item->with_sum_func;
   with_field= orig_item->with_field;
   name= item_arg->name;
-  with_subselect=  orig_item->with_subselect;
+  m_with_subquery= orig_item->with_subquery();
 
   if ((expr_value= orig_item->get_cache(thd)))
     expr_value->setup(thd, orig_item);

sql/item.h

@@ -703,9 +703,6 @@ public:
   bool fixed;                           /* If item fixed with fix_fields */
   bool is_autogenerated_name;           /* indicate was name of this Item
                                            autogenerated or set by user */
-  bool with_subselect;                  /* If this item is a subselect or some
-                                           of its arguments is or contains a
-                                           subselect */
   // alloc & destruct is done as start of select on THD::mem_root
   Item(THD *thd);
   /*
@@ -1871,9 +1868,10 @@ public:
   virtual bool is_outer_field() const { DBUG_ASSERT(fixed); return FALSE; }
 
   /**
-    Checks if this item or any of its decendents contains a subquery.
+    Checks if this item or any of its decendents contains a subquery. This is a
+    replacement of the former Item::has_subquery() and Item::with_subselect.
   */
-  virtual bool has_subquery() const { return with_subselect; }
+  virtual bool with_subquery() const { DBUG_ASSERT(fixed); return false; }
 
   Item* set_expr_cache(THD *thd);
 
@@ -1949,6 +1947,21 @@ inline Item* get_item_copy (THD *thd, MEM_ROOT *mem_root, T* item)
 }	
 
 
+/*
+  This class is a replacement for the former member Item::with_subselect.
+  Determines if the descendant Item is a subselect or some of
+  its arguments is or contains a subselect.
+*/
+class With_subquery_cache
+{
+protected:
+  bool m_with_subquery;
+public:
+  With_subquery_cache(): m_with_subquery(false) { }
+  void join(const Item *item) { m_with_subquery|= item->with_subquery(); }
+};
+
+
 class Type_geometry_attributes
 {
   uint m_geometry_type;
@@ -4268,7 +4281,8 @@ public:
 */
 class Item_func_or_sum: public Item_result_field,
                         public Item_args,
-                        public Used_tables_and_const_cache
+                        public Used_tables_and_const_cache,
+                        public With_subquery_cache
 {
 protected:
   bool agg_arg_charsets(DTCollation &c, Item **items, uint nitems,
@@ -4351,6 +4365,7 @@ public:
     Used_tables_and_const_cache(item) { }
   Item_func_or_sum(THD *thd, List<Item> &list):
     Item_result_field(thd), Item_args(thd, list) { }
+  bool with_subquery() const { DBUG_ASSERT(fixed); return m_with_subquery; }
   bool walk(Item_processor processor, bool walk_subquery, void *arg)
   {
     if (walk_args(processor, walk_subquery, arg))
@@ -4565,9 +4580,9 @@ public:
   /**
     Checks if the item tree that ref points to contains a subquery.
   */
-  virtual bool has_subquery() const 
-  { 
-    return (*ref)->has_subquery();
+  virtual bool with_subquery() const
+  {
+    return (*ref)->with_subquery();
   }
   Item *get_copy(THD *thd, MEM_ROOT *mem_root)
   { return get_item_copy<Item_ref>(thd, mem_root, this); }
@@ -4684,7 +4699,8 @@ class Expression_cache_tracker;
   The objects of this class can store its values in an expression cache.
 */
 
-class Item_cache_wrapper :public Item_result_field
+class Item_cache_wrapper :public Item_result_field,
+                          public With_subquery_cache
 {
 private:
   /* Pointer on the cached expression */
@@ -4711,6 +4727,7 @@ public:
 
   enum Type type() const { return EXPR_CACHE_ITEM; }
   enum Type real_type() const { return orig_item->type(); }
+  bool with_subquery() const { DBUG_ASSERT(fixed); return m_with_subquery; }
 
   bool set_cache(THD *thd);
   Expression_cache_tracker* init_tracker(MEM_ROOT *mem_root);

sql/item_cmpfunc.cc

@@ -1365,7 +1365,7 @@ bool Item_in_optimizer::fix_fields(THD *thd, Item **ref)
   }
   if (args[1]->maybe_null)
     maybe_null=1;
-  with_subselect= 1;
+  m_with_subquery= true;
   with_sum_func= with_sum_func || args[1]->with_sum_func;
   with_field= with_field || args[1]->with_field;
   used_tables_and_const_cache_join(args[1]);
@@ -4603,7 +4603,7 @@ Item_cond::fix_fields(THD *thd, Item **ref)
   
     with_sum_func|=    item->with_sum_func;
     with_field|=       item->with_field;
-    with_subselect|=   item->has_subquery();
+    m_with_subquery|=  item->with_subquery();
     with_window_func|= item->with_window_func;
     maybe_null|=       item->maybe_null;
   }
@@ -6607,7 +6607,7 @@ bool Item_equal::fix_fields(THD *thd, Item **ref)
     used_tables_cache|= item->used_tables();
     tmp_table_map= item->not_null_tables();
     not_null_tables_cache|= tmp_table_map;
-    DBUG_ASSERT(!item->with_sum_func && !item->with_subselect);
+    DBUG_ASSERT(!item->with_sum_func && !item->with_subquery());
     if (item->maybe_null)
       maybe_null= 1;
     if (!item->get_item_equal())

sql/item_cmpfunc.h

@@ -356,7 +356,7 @@ public:
   Item_in_optimizer(THD *thd, Item *a, Item *b):
     Item_bool_func(thd, a, b), cache(0), expr_cache(0),
     save_cache(0), result_for_null_param(UNKNOWN)
-  { with_subselect= true; }
+  { m_with_subquery= true; }
   bool fix_fields(THD *, Item **);
   bool fix_left(THD *thd);
   table_map not_null_tables() const { return 0; }

sql/item_func.cc

@@ -362,7 +362,7 @@ Item_func::fix_fields(THD *thd, Item **ref)
       with_window_func= with_window_func || item->with_window_func;
       with_field= with_field || item->with_field;
       used_tables_and_const_cache_join(item);
-      with_subselect|=        item->has_subquery();
+      m_with_subquery|= item->with_subquery();
     }
   }
   if (check_arguments())
@@ -3248,7 +3248,7 @@ udf_handler::fix_fields(THD *thd, Item_func_or_sum *func,
 	func->maybe_null=1;
       func->with_sum_func= func->with_sum_func || item->with_sum_func;
       func->with_field= func->with_field || item->with_field;
-      func->with_subselect|= item->with_subselect;
+      func->With_subquery_cache::join(item);
       func->used_tables_and_const_cache_join(item);
       f_args.arg_type[i]=item->result_type();
     }

sql/item_row.cc

@@ -64,7 +64,7 @@ bool Item_row::fix_fields(THD *thd, Item **ref)
     with_sum_func= with_sum_func || item->with_sum_func;
     with_window_func = with_window_func || item->with_window_func;
     with_field= with_field || item->with_field;
-    with_subselect|= item->with_subselect;
+    m_with_subquery|= item->with_subquery();
   }
   fixed= 1;
   return FALSE;

sql/item_row.h

@@ -35,7 +35,8 @@
 */
 class Item_row: public Item,
                 private Item_args,
-                private Used_tables_and_const_cache
+                private Used_tables_and_const_cache,
+                private With_subquery_cache
 {
   table_map not_null_tables_cache;
   /**
@@ -52,6 +53,7 @@ public:
     not_null_tables_cache(0), with_null(0)
   { }
 
+  bool with_subquery() const { DBUG_ASSERT(fixed); return m_with_subquery; }
   enum Type type() const { return ROW_ITEM; };
   const Type_handler *type_handler() const { return &type_handler_row; }
   void illegal_method_call(const char *);

sql/item_subselect.cc

@@ -64,7 +64,6 @@ Item_subselect::Item_subselect(THD *thd_arg):
 #ifndef DBUG_OFF
   exec_counter= 0;
 #endif
-  with_subselect= 1;
   reset();
   /*
     Item value is NULL if select_result_interceptor didn't change this value

sql/item_subselect.h

@@ -182,6 +182,7 @@ public:
     return null_value;
   }
   bool fix_fields(THD *thd, Item **ref);
+  bool with_subquery() const { DBUG_ASSERT(fixed); return true; }
   bool mark_as_dependent(THD *thd, st_select_lex *select, Item *item);
   void fix_after_pullout(st_select_lex *new_parent, Item **ref, bool merge);
   void recalc_used_tables(st_select_lex *new_parent, bool after_pullout);

sql/item_sum.cc

@@ -1126,7 +1126,7 @@ Item_sum_num::fix_fields(THD *thd, Item **ref)
     if (args[i]->fix_fields(thd, args + i) || args[i]->check_cols(1))
       return TRUE;
     set_if_bigger(decimals, args[i]->decimals);
-    with_subselect|= args[i]->with_subselect;
+    m_with_subquery|= args[i]->with_subquery();
     with_window_func|= args[i]->with_window_func;
   }
   result_field=0;
@@ -1157,7 +1157,7 @@ Item_sum_hybrid::fix_fields(THD *thd, Item **ref)
   if ((!item->fixed && item->fix_fields(thd, args)) ||
       (item= args[0])->check_cols(1))
     return TRUE;
-  with_subselect= args[0]->with_subselect;
+  m_with_subquery= args[0]->with_subquery();
   with_window_func|= args[0]->with_window_func;
 
   fix_length_and_dec();
@@ -3447,7 +3447,7 @@ Item_func_group_concat::fix_fields(THD *thd, Item **ref)
          args[i]->fix_fields(thd, args + i)) ||
         args[i]->check_cols(1))
       return TRUE;
-    with_subselect|= args[i]->with_subselect;
+    m_with_subquery|= args[i]->with_subquery();
     with_window_func|= args[i]->with_window_func;
   }
 

sql/item_windowfunc.cc

@@ -238,8 +238,8 @@ bool Item_sum_hybrid_simple::fix_fields(THD *thd, Item **ref)
       return TRUE;
   }
   Type_std_attributes::set(args[0]);
-  for (uint i= 0; i < arg_count && !with_subselect; i++)
-    with_subselect= with_subselect || args[i]->with_subselect;
+  for (uint i= 0; i < arg_count && !m_with_subquery; i++)
+    m_with_subquery|= args[i]->with_subquery();
 
   Item *item2= args[0]->real_item();
   if (item2->type() == Item::FIELD_ITEM)

sql/opt_subselect.cc

@@ -1629,7 +1629,7 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
 
   // The subqueries were replaced for Item_int(1) earlier
   subq_pred->reset_strategy(SUBS_SEMI_JOIN);       // for subsequent executions
-  /*TODO: also reset the 'with_subselect' there. */
+  /*TODO: also reset the 'm_with_subquery' there. */
 
   /* n. Adjust the parent_join->table_count counter */
   uint table_no= parent_join->table_count;

sql/sql_select.cc

@@ -12810,7 +12810,7 @@ remove_const(JOIN *join,ORDER *first_order, COND *cond,
       *simple_order=0;				// Must do a temp table to sort
     else if (!(order_tables & not_const_tables))
     {
-      if (order->item[0]->has_subquery())
+      if (order->item[0]->with_subquery())
       {
         /*
           Delay the evaluation of constant ORDER and/or GROUP expressions that