join_free now is method of JOIN and commented

dependence should mean uncacheability

sql/item_subselect.cc

@@ -622,10 +622,10 @@ Item_in_subselect::single_value_transformer(JOIN *join,
 		       (char *)"<no matter>",
 		       (char *)in_left_expr_name);
 
-    unit->dependent= 1;
+    unit->dependent= unit->uncacheable= 1;
   }
 
-  select_lex->dependent= 1;
+  select_lex->dependent= select_lex->uncacheable= 1;
   Item *item;
 
   item= (Item*) select_lex->item_list.head();
@@ -747,13 +747,12 @@ Item_in_subselect::row_value_transformer(JOIN *join,
       DBUG_RETURN(RES_ERROR);
     }
     thd->lex.current_select= current;
-
-    unit->dependent= 1;
+    unit->dependent= unit->uncacheable= 1;
   }
 
   uint n= left_expr->cols();
 
-  select_lex->dependent= 1;
+  select_lex->dependent= select_lex->uncacheable= 1;
   select_lex->setup_ref_array(thd,
 			      select_lex->order_list.elements +
 			      select_lex->group_list.elements);

sql/sql_lex.cc

@@ -1195,16 +1195,16 @@ void st_select_lex::mark_as_dependent(SELECT_LEX *last)
     found table as depended (of select where was found table)
   */
   for (SELECT_LEX *s= this;
-       s &&s != last;
+       s && s != last;
        s= s->outer_select())
     if ( !s->dependent )
     {
       // Select is dependent of outer select
-      s->dependent= 1;
-      s->master_unit()->dependent= 1;
+      s->dependent= s->uncacheable= 1;
+      SELECT_LEX_UNIT *munit= s->master_unit();
+      munit->dependent= munit->uncacheable= 1;
       //Tables will be reopened many times
-      for (TABLE_LIST *tbl=
-	     s->get_table_list();
+      for (TABLE_LIST *tbl= s->get_table_list();
 	   tbl;
 	   tbl= tbl->next)
 	tbl->shared= 1;

sql/sql_select.cc

@@ -62,7 +62,6 @@ static store_key *get_store_key(THD *thd,
 static bool make_simple_join(JOIN *join,TABLE *tmp_table);
 static bool make_join_select(JOIN *join,SQL_SELECT *select,COND *item);
 static void make_join_readinfo(JOIN *join,uint options);
-static void join_free(JOIN *join, bool full);
 static bool only_eq_ref_tables(JOIN *join, ORDER *order, table_map tables);
 static void update_depend_map(JOIN *join);
 static void update_depend_map(JOIN *join, ORDER *order);
@@ -1232,7 +1231,7 @@ JOIN::exec()
       DBUG_PRINT("info",("Creating group table"));
       
       /* Free first data from old join */
-      join_free(curr_join, 0);
+      curr_join->join_free(0);
       if (make_simple_join(curr_join, curr_tmp_table))
 	DBUG_VOID_RETURN;
       calc_group_buffer(curr_join, group_list);
@@ -1327,7 +1326,7 @@ JOIN::exec()
     if (curr_tmp_table->distinct)
       curr_join->select_distinct=0;		/* Each row is unique */
     
-    join_free(curr_join, 0);			/* Free quick selects */
+    curr_join->join_free(0);			/* Free quick selects */
     if (select_distinct && ! group_list)
     {
       thd->proc_info="Removing duplicates";
@@ -1501,7 +1500,7 @@ JOIN::cleanup()
   }
 
   lock=0;                                     // It's faster to unlock later
-  join_free(this, 1);
+  join_free(1);
    if (exec_tmp_table1)
      free_tmp_table(thd, exec_tmp_table1);
    if (exec_tmp_table2)
@@ -3667,26 +3666,37 @@ bool error_if_full_join(JOIN *join)
 }
 
 
-static void
-join_free(JOIN *join, bool full)
+/*
+  Free resources of given join
+
+  SYNOPSIS
+    JOIN::join_free()
+    fill - true if we should free all resources, call with full==1 should be
+           last, before it this function can be called with full==0
+
+  NOTE: with subquery this function definitely will be called several times,
+    but even for simple query it can be called several times.
+*/
+void
+JOIN::join_free(bool full)
 {
   JOIN_TAB *tab,*end;
   DBUG_ENTER("join_free");
 
-  if (join->table)
+  if (table)
   {
     /*
       Only a sorted table may be cached.  This sorted table is always the
       first non const table in join->table
     */
-    if (join->tables > join->const_tables) // Test for not-const tables
+    if (tables > const_tables) // Test for not-const tables
     {
-      free_io_cache(join->table[join->const_tables]);
-      filesort_free_buffers(join->table[join->const_tables]);
+      free_io_cache(table[const_tables]);
+      filesort_free_buffers(table[const_tables]);
     }
-    if (!full && join->select_lex->dependent)
+    if (!full && select_lex->uncacheable)
     {
-      for (tab=join->join_tab,end=tab+join->tables ; tab != end ; tab++)
+      for (tab= join_tab, end= tab+tables; tab != end; tab++)
       {
 	if (tab->table)
 	{
@@ -3703,7 +3713,7 @@ join_free(JOIN *join, bool full)
     }
     else
     {
-      for (tab=join->join_tab,end=tab+join->tables ; tab != end ; tab++)
+      for (tab= join_tab, end= tab+tables; tab != end; tab++)
       {
 	delete tab->select;
 	delete tab->quick;
@@ -3729,25 +3739,25 @@ join_free(JOIN *join, bool full)
 	}
 	end_read_record(&tab->read_record);
       }
-      join->table= 0;
+      table= 0;
     }
   }
   /*
     We are not using tables anymore
     Unlock all tables. We may be in an INSERT .... SELECT statement.
   */
-  if ((full || !join->select_lex->dependent) &&
-      join->lock && join->thd->lock &&
-      !(join->select_options & SELECT_NO_UNLOCK))
+  if ((full || !select_lex->uncacheable) &&
+      lock && thd->lock &&
+      !(select_options & SELECT_NO_UNLOCK))
   {
-    mysql_unlock_read_tables(join->thd, join->lock);// Don't free join->lock
-    join->lock=0;
+    mysql_unlock_read_tables(thd, lock);// Don't free join->lock
+    lock=0;
   }
   if (full)
   {
-    join->group_fields.delete_elements();
-    join->tmp_table_param.copy_funcs.delete_elements();
-    join->tmp_table_param.cleanup();
+    group_fields.delete_elements();
+    tmp_table_param.copy_funcs.delete_elements();
+    tmp_table_param.cleanup();
   }
   DBUG_VOID_RETURN;
 }
@@ -5459,7 +5469,7 @@ do_select(JOIN *join,List<Item> *fields,TABLE *table,Procedure *procedure)
 	The following will unlock all cursors if the command wasn't an
 	update command
       */
-      join_free(join, 0);				// Unlock all cursors
+      join->join_free(0);				// Unlock all cursors
       if (join->result->send_eof())
 	error= 1;				// Don't send error
     }

sql/sql_select.h

@@ -280,6 +280,7 @@ class JOIN :public Sql_alloc
 			  Item_sum ***func);
   int rollup_send_data(uint idx);
   bool test_in_subselect(Item **where);
+  void join_free(bool full);
   void clear();
   bool save_join_tab();
 };