Get rid of Window_func_runner::first_run

We can call setup_partition_border_check() from
JOIN::make_aggr_tables_info(), provided that call is made after
appropriate set_items_ref_array() call.

sql/sql_select.cc

@@ -2334,6 +2334,14 @@ bool JOIN::make_aggr_tables_info()
     curr_tab->fields= &tmp_fields_list1;
     set_postjoin_aggr_write_func(curr_tab);
 
+    // psergey-todo: this is probably an incorrect place:
+    if (select_lex->window_funcs.elements)
+    {
+      curr_tab->window_funcs= new Window_funcs_computation;
+      if (curr_tab->window_funcs->setup(thd, &select_lex->window_funcs))
+        DBUG_RETURN(true);
+    }
+
     tmp_table_param.func_count= 0;
     tmp_table_param.field_count+= tmp_table_param.func_count;
     if (sort_and_group || curr_tab->table->group)
@@ -2698,14 +2706,6 @@ JOIN::create_postjoin_aggr_table(JOIN_TAB *tab, List<Item> *table_fields,
   tab->table= table;
   table->reginfo.join_tab= tab;
 
-  // psergey-todo: this is probably an incorrect place:
-  if (select_lex->window_funcs.elements)
-  {
-    tab->window_funcs= new Window_funcs_computation;
-    if (tab->window_funcs->setup(thd, &select_lex->window_funcs))
-      goto err;
-  }
-
   /* if group or order on first table, sort first */
   if (group_list && simple_group)
   {
@@ -2749,6 +2749,7 @@ JOIN::create_postjoin_aggr_table(JOIN_TAB *tab, List<Item> *table_fields,
       order= NULL;
     }
   }
+
   DBUG_RETURN(false);
 
 err:

sql/sql_window.cc

@@ -1485,6 +1485,8 @@ bool Window_func_runner::setup(THD *thd)
                                         spec->order_list->first);
   filesort= new (thd->mem_root) Filesort(sort_order, HA_POS_ERROR, NULL);
 
+  win_func->setup_partition_border_check(thd);
+
   Item_sum::Sumfunctype type= win_func->window_func()->sum_func();
   switch (type) 
   {
@@ -1521,7 +1523,6 @@ bool Window_func_runner::setup(THD *thd)
       DBUG_ASSERT(0);
   }
 
-  first_run= true;
   return false;
 }
 
@@ -1533,29 +1534,6 @@ bool Window_func_runner::exec(JOIN *join)
 {
   THD *thd= join->thd;
 
-  /*
-    We have to call setup_partition_border_check here.
-    
-    The reason is as follows: 
-    When computing the value of sorting criteria from OVER (PARTITION ...
-    ORDER BY ...) clauses, we need to read temp.table fields.
-
-    This is achieved by ORDER::item being Item** object, which points into
-    ref_pointer_array.
-    Ref_pointer_array initially points to source table fields. 
-    At execution phase, it is set to point to the temp.table fields.
-     
-    We need to use items after this step is done.
-    TODO: an alternative is to use something that points into
-    ref_pointer_array, too. Something like wrap order->item in an Item_ref
-    object.
-  */
-  if (first_run)
-  {
-    win_func->setup_partition_border_check(thd);
-    first_run= false;
-  }
-
   if (create_sort_index(thd, join, &join->join_tab[join->top_join_tab_count],
                         filesort))
     return true;

sql/sql_window.h

@@ -159,7 +159,6 @@ class Window_func_runner : public Sql_alloc
   /* The function to use for computation*/
   window_compute_func_t compute_func;
   
-  bool first_run;
 public:
   Window_func_runner(Item_window_func *win_func_arg) :
     win_func(win_func_arg)