changes based on partial revie of task 577 (SCRUM)

10 files changed, 149 insertions, 116 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 8ca7f650054..ba50039cc72 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -37,16 +37,22 @@ void item_init(void)
 Item::Item():
   fixed(0)
 {
-  marker=0;
+  marker= 0;
   maybe_null=null_value=with_sum_func=unsigned_flag=0;
-  name=0;
-  decimals=0; max_length=0;
-  next=current_thd->free_list;			// Put in free list
-  current_thd->free_list=this;
+  name= 0;
+  decimals= 0; max_length= 0;
+  THD *thd= current_thd;
+  next= thd->free_list;			// Put in free list
+  thd->free_list= this;
   loop_id= 0;
 }
 
-Item::Item(Item &item):
+/*
+  Constructor used by Item_field, Item_ref & agregate (sum) functions.
+  Used for duplicating lists in processing queries with temporary
+  tables
+*/
+Item::Item(THD *thd, Item &item):
   loop_id(0),
   str_value(item.str_value),
   name(item.name),
@@ -59,12 +65,13 @@ Item::Item(Item &item):
   with_sum_func(item.with_sum_func),
   fixed(item.fixed)
 {
-  next=current_thd->free_list;			// Put in free list
-  current_thd->free_list= this;
+  next=thd->free_list;			// Put in free list
+  thd->free_list= this;
 }
 
-Item_ident::Item_ident(Item_ident &item):
-  Item(item),
+// Constructor used by Item_field & Item_ref (see Item comment)
+Item_ident::Item_ident(THD *thd, Item_ident &item):
+  Item(thd, item),
   db_name(item.db_name),
   table_name(item.table_name),
   field_name(item.field_name),
@@ -165,8 +172,9 @@ Item_field::Item_field(Field *f) :Item_ident(NullS,f->table_name,f->field_name)
   fixed= 1; // This item is not needed in fix_fields
 }
 
-Item_field::Item_field(Item_field &item):
-  Item_ident(item),
+// Constructor need to process subselect with temporary tables (see Item)
+Item_field::Item_field(THD *thd, Item_field &item):
+  Item_ident(thd, item),
   field(item.field),
   result_field(item.result_field)
 {}
@@ -281,9 +289,9 @@ table_map Item_field::used_tables() const
   return (depended_from? RAND_TABLE_BIT : field->table->map);
 }
 
-Item * Item_field::get_tmp_table_item()
+Item *Item_field::get_tmp_table_item(THD *thd)
 {
-  Item_field *new_item= new Item_field(*this);
+  Item_field *new_item= new Item_field(thd, *this);
   if (new_item)
     new_item->field= new_item->result_field;
   return new_item;
@@ -617,7 +625,7 @@ bool Item_field::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
       thd->net.last_errno= 0;
 #endif
       Item **refer= (Item **)not_found_item;
-      uint counter= 0;
+      uint counter;
       // Prevent using outer fields in subselects, that is not supported now
       SELECT_LEX *cursel=(SELECT_LEX *) thd->lex.current_select;
       if (outer_resolving ||
@@ -658,19 +666,21 @@ bool Item_field::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
 	}
 
 	Item_ref *r;
-	*ref= r= new Item_ref(last->ref_pointer_array + counter-1
+	*ref= r= new Item_ref(last->ref_pointer_array + counter
 			      , (char *)table_name,
 			   (char *)field_name);
 	if (!r)
 	  return 1;
 	if (r->fix_fields(thd, tables, ref) || r->check_cols(1))
 	  return 1;
+	// store pointer on SELECT_LEX from wich item is dependent
 	r->depended_from= last;
 	cursel->mark_as_dependent(last);
 	return 0;
       }
       else
       {
+	// store pointer on SELECT_LEX from wich item is dependent
 	depended_from= last;
 	/*
 	  Mark all selects from resolved to 1 before select where was 
@@ -1071,7 +1081,7 @@ bool Item_field::send(Protocol *protocol, String *buffer)
 
 bool Item_ref::fix_fields(THD *thd,TABLE_LIST *tables, Item **reference)
 {
-  uint counter= 0;
+  uint counter;
   if (!ref)
   {
     TABLE_LIST *where= 0;
@@ -1142,6 +1152,7 @@ bool Item_ref::fix_fields(THD *thd,TABLE_LIST *tables, Item **reference)
 	Item_field* f;
 	if (!((*reference)= f= new Item_field(tmp)))
 	  return 1;
+	// store pointer on SELECT_LEX from wich item is dependent
 	f->depended_from= last;
 	thd->lex.current_select->mark_as_dependent(last);
 	return 0;
@@ -1154,7 +1165,10 @@ bool Item_ref::fix_fields(THD *thd,TABLE_LIST *tables, Item **reference)
 		   "forward reference in item list");
 	  return -1;
 	}
-	ref= (depended_from= last)->ref_pointer_array + counter-1;
+        /*
+	  depended_from: pointer on SELECT_LEX from wich item is dependent
+	*/
+	ref= (depended_from= last)->ref_pointer_array + counter;
 	thd->lex.current_select->mark_as_dependent(last);
       }
     }
@@ -1168,7 +1182,7 @@ bool Item_ref::fix_fields(THD *thd,TABLE_LIST *tables, Item **reference)
 		 "forward reference in item list");
 	return -1;
       }
-      ref= thd->lex.current_select->ref_pointer_array + counter-1;
+      ref= thd->lex.current_select->ref_pointer_array + counter;
     }
   }
 
diff --git a/sql/item.h b/sql/item.h
index 84ddcb98baf..3c66014165a 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -53,8 +53,12 @@ public:
 
   // alloc & destruct is done as start of select using sql_alloc
   Item();
-  // copy constructor used by Item_field, Item_ref & agregate (sum) functions
-  Item(Item &item);
+  /*
+     Constructor used by Item_field, Item_ref & agregate (sum) functions.
+     Used for duplicating lists in processing queries with temporary
+     tables
+  */
+  Item(THD *thd, Item &item);
   virtual ~Item() { name=0; }		/*lint -e1509 */
   void set_name(const char *str,uint length=0);
   void init_make_field(Send_field *tmp_field,enum enum_field_types type);
@@ -93,8 +97,8 @@ public:
   virtual bool get_time(TIME *ltime);
   virtual bool is_null() { return 0; };
   virtual void top_level_item() {}
-  virtual Item * get_same() { return this; }
-  virtual Item * get_tmp_table_item() { return get_same(); }
+  virtual Item *copy_or_same(THD *thd) { return this; }
+  virtual Item *get_tmp_table_item(THD *thd) { return copy_or_same(thd); }
 
   virtual bool binary() const
   { return str_value.charset()->state & MY_CS_BINSORT ? 1 : 0 ; }
@@ -129,8 +133,8 @@ public:
     :db_name(db_name_par), table_name(table_name_par),
      field_name(field_name_par), depended_from(0), outer_resolving(0)
     { name = (char*) field_name_par; }
-  // copy constructor used by Item_field & Item_ref
-  Item_ident(Item_ident &item);
+  // Constructor used by Item_field & Item_ref (see Item comment)
+  Item_ident(THD *thd, Item_ident &item);
   const char *full_name() const;
   void set_outer_resolving() { outer_resolving= 1; }
 };
@@ -147,8 +151,8 @@ public:
 	     const char *field_name_par)
     :Item_ident(db_par,table_name_par,field_name_par),field(0),result_field(0)
   {}
-  // copy constructor need to process subselect with temporary tables
-  Item_field(Item_field &item);
+  // Constructor need to process subselect with temporary tables (see Item)
+  Item_field(THD *thd, Item_field &item);
   Item_field(Field *field);
   enum Type type() const { return FIELD_ITEM; }
   bool eq(const Item *item, bool binary_cmp) const;
@@ -177,7 +181,7 @@ public:
   bool get_date(TIME *ltime,bool fuzzydate);  
   bool get_time(TIME *ltime);  
   bool is_null() { return field->is_null(); }
-  Item * get_tmp_table_item();
+  Item *get_tmp_table_item(THD *thd);
   friend class Item_default_value;
 };
 
@@ -437,10 +441,10 @@ class Item_result_field :public Item	/* Item with result field */
 public:
   Field *result_field;				/* Save result here */
   Item_result_field() :result_field(0) {}
-  Item_result_field(Item_result_field &item): Item(item)
-  {
-    result_field= item.result_field;
-  }
+  // Constructor used for Item_sum (see Item comment)
+  Item_result_field(THD *thd, Item_result_field &item):
+    Item(thd, item), result_field(item.result_field)
+  {}
   ~Item_result_field() {}			/* Required with gcc 2.95 */
   Field *tmp_table_field() { return result_field; }
   Field *tmp_table_field(TABLE *t_arg) { return result_field; }
@@ -457,8 +461,9 @@ public:
     :Item_ident(db_par,table_name_par,field_name_par),ref(0) {}
   Item_ref(Item **item, char *table_name_par,char *field_name_par)
     :Item_ident(NullS,table_name_par,field_name_par),ref(item) {}
-  // copy constructor need to process subselect with temporary tables
-  Item_ref(Item_ref &item): Item_ident(item), ref(item.ref) {}
+  // Constructor need to process subselect with temporary tables (see Item)
+  Item_ref(THD *thd, Item_ref &item)
+    :Item_ident(thd, item), ref(item.ref) {}
   enum Type type() const		{ return REF_ITEM; }
   bool eq(const Item *item, bool binary_cmp) const
   { return ref && (*ref)->eq(item, binary_cmp); }
@@ -527,6 +532,12 @@ public:
 class Item_ref_on_list_position: public Item_ref_null_helper
 {
 protected:
+  /* 
+     select_lex used for:
+     1) receiving expanded variant of item list (to check max possible 
+        nunber of elements);
+     2) to have access to  ref_pointer_array, via wich item will refered.
+  */
   st_select_lex *select_lex;
   uint pos;
 public:
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 1db123f2a47..e189bf2910e 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -1063,7 +1063,8 @@ int in_vector::find(Item *item)
 }
 
 in_string::in_string(uint elements,qsort_cmp cmp_func)
-  :in_vector(elements,sizeof(String),cmp_func),tmp(buff,sizeof(buff),default_charset_info)
+  :in_vector(elements, sizeof(String), cmp_func),
+   tmp(buff, sizeof(buff), default_charset_info)
 {}
 
 in_string::~in_string()
@@ -1102,11 +1103,7 @@ in_row::in_row(uint elements, Item * item)
 in_row::~in_row()
 {
   if (base)
-  {
-    cmp_item_row *arr= (cmp_item_row *) base;
-    for (uint i=0 ; i < count ; i++)
-      arr[i].~cmp_item_row();
-  }
+    delete [] (cmp_item_row*) base;
 }
 
 byte *in_row::get_value(Item *item)
diff --git a/sql/item_func.cc b/sql/item_func.cc
index e76fd618eb1..71e25e8f73a 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -294,14 +294,11 @@ void Item_func::fix_num_length_and_dec()
   max_length=float_length(decimals);
 }
 
-Item * Item_func::get_tmp_table_item()
+Item *Item_func::get_tmp_table_item(THD *thd)
 {
   if (!with_sum_func && !const_item())
-  {
     return new Item_field(result_field);
-  }
-  else
-    return get_same();
+  return copy_or_same(thd);
 }
 
 String *Item_int_func::val_str(String *str)
diff --git a/sql/item_func.h b/sql/item_func.h
index 6368b537dc5..fbf9e712092 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -134,7 +134,7 @@ public:
   Field *tmp_table_field() { return result_field; }
   Field *tmp_table_field(TABLE *t_arg);
   void set_outer_resolving();
-  Item * get_tmp_table_item();
+  Item *get_tmp_table_item(THD *thd);
 };
 
 
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 13e70358b05..7ded4921180 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -41,8 +41,9 @@ Item_sum::Item_sum(List<Item> &list)
   list.empty();					// Fields are used
 }
 
-Item_sum::Item_sum(Item_sum &item):
-  Item_result_field(item), quick_group(item.quick_group)
+// Constructor used in processing select with temporary tebles
+Item_sum::Item_sum(THD *thd, Item_sum &item):
+  Item_result_field(thd, item), quick_group(item.quick_group)
 {
   arg_count= item.arg_count;
   if (arg_count <= 2)
@@ -96,9 +97,9 @@ void Item_sum::fix_num_length_and_dec()
   max_length=float_length(decimals);
 }
 
-Item * Item_sum::get_tmp_table_item()
+Item *Item_sum::get_tmp_table_item(THD *thd)
 {
-  Item_sum* sum_item= (Item_sum *) get_same();
+  Item_sum* sum_item= (Item_sum *) copy_or_same(thd);
   if (sum_item && sum_item->result_field)	   // If not a const sum func
   {
     Field *result_field= sum_item->result_field;
diff --git a/sql/item_sum.h b/sql/item_sum.h
index 7f7b5e70f41..69966aa5796 100644
--- a/sql/item_sum.h
+++ b/sql/item_sum.h
@@ -55,7 +55,7 @@ public:
   }
   Item_sum(List<Item> &list);
   //Copy constructor, need to perform subselects with temporary tables
-  Item_sum(Item_sum &item);
+  Item_sum(THD *thd, Item_sum &item);
   ~Item_sum() { result_field=0; }
 
   enum Type type() const { return SUM_FUNC_ITEM; }
@@ -77,7 +77,7 @@ public:
   void print(String *str);
   void fix_num_length_and_dec();
   virtual bool setup(THD *thd) {return 0;}
-  Item * get_tmp_table_item();
+  Item *get_tmp_table_item(THD *thd);
 };
 
 
@@ -88,7 +88,7 @@ public:
   Item_sum_num(Item *item_par) :Item_sum(item_par) {}
   Item_sum_num(Item *a, Item* b) :Item_sum(a,b) {}
   Item_sum_num(List<Item> &list) :Item_sum(list) {}
-  Item_sum_num(Item_sum_num &item) :Item_sum(item) {}
+  Item_sum_num(THD *thd, Item_sum_num &item) :Item_sum(thd, item) {}
   bool fix_fields(THD *, TABLE_LIST *, Item **);
   longlong val_int() { return (longlong) val(); } /* Real as default */
   String *val_str(String*str);
@@ -104,7 +104,7 @@ class Item_sum_int :public Item_sum_num
 public:
   Item_sum_int(Item *item_par) :Item_sum_num(item_par) {}
   Item_sum_int(List<Item> &list) :Item_sum_num(list) {}
-  Item_sum_int(Item_sum_int &item) :Item_sum_num(item) {}
+  Item_sum_int(THD *thd, Item_sum_int &item) :Item_sum_num(thd, item) {}
   double val() { return (double) val_int(); }
   String *val_str(String*str);
   enum Item_result result_type () const { return INT_RESULT; }
@@ -118,7 +118,8 @@ class Item_sum_sum :public Item_sum_num
 
   public:
   Item_sum_sum(Item *item_par) :Item_sum_num(item_par),sum(0.0) {}
-  Item_sum_sum(Item_sum_sum &item) :Item_sum_num(item), sum(item.sum) {}
+  Item_sum_sum(THD *thd, Item_sum_sum &item) 
+    :Item_sum_num(thd, item), sum(item.sum) {}
   enum Sumfunctype sum_func () const {return SUM_FUNC;}
   void reset();
   bool add();
@@ -126,7 +127,7 @@ class Item_sum_sum :public Item_sum_num
   void reset_field();
   void update_field(int offset);
   const char *func_name() const { return "sum"; }
-  Item * get_same() { return new Item_sum_sum(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_sum(thd, *this); }
 };
 
 
@@ -139,9 +140,9 @@ class Item_sum_count :public Item_sum_int
   Item_sum_count(Item *item_par)
     :Item_sum_int(item_par),count(0),used_table_cache(~(table_map) 0)
   {}
-  Item_sum_count(Item_sum_count &item): Item_sum_int(item),
-					count(item.count),
-					used_table_cache(item.used_table_cache)
+  Item_sum_count(THD *thd, Item_sum_count &item)
+    :Item_sum_int(thd, item), count(item.count),
+     used_table_cache(item.used_table_cache)
   {}
   table_map used_tables() const { return used_table_cache; }
   bool const_item() const { return !used_table_cache; }
@@ -153,7 +154,7 @@ class Item_sum_count :public Item_sum_int
   void reset_field();
   void update_field(int offset);
   const char *func_name() const { return "count"; }
-  Item * get_same() { return new Item_sum_count(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_count(thd, *this); }
 };
 
 
@@ -206,15 +207,15 @@ class Item_sum_count_distinct :public Item_sum_int
      tmp_table_param(0), tree(&tree_base), original(0), use_tree(0),
      always_null(0)
   { quick_group= 0; }
-  Item_sum_count_distinct(Item_sum_count_distinct &item):
-    Item_sum_int(item), table(item.table),
-    used_table_cache(item.used_table_cache),
-    field_lengths(item.field_lengths), tmp_table_param(item.tmp_table_param),
-    tree(item.tree), original(&item), key_length(item.key_length),
-    max_elements_in_tree(item.max_elements_in_tree),
-    rec_offset(item.rec_offset), use_tree(item.use_tree),
-    always_null(item.always_null)
-    {}
+  Item_sum_count_distinct(THD *thd, Item_sum_count_distinct &item)
+    :Item_sum_int(thd, item), table(item.table),
+     used_table_cache(item.used_table_cache),
+     field_lengths(item.field_lengths), tmp_table_param(item.tmp_table_param),
+     tree(item.tree), original(&item), key_length(item.key_length),
+     max_elements_in_tree(item.max_elements_in_tree),
+     rec_offset(item.rec_offset), use_tree(item.use_tree),
+     always_null(item.always_null)
+  {}
   ~Item_sum_count_distinct();
   table_map used_tables() const { return used_table_cache; }
   enum Sumfunctype sum_func () const { return COUNT_DISTINCT_FUNC; }
@@ -225,7 +226,10 @@ class Item_sum_count_distinct :public Item_sum_int
   void update_field(int offset) { return ; }	// Never called
   const char *func_name() const { return "count_distinct"; }
   bool setup(THD *thd);
-  Item * get_same() { return new Item_sum_count_distinct(*this); }
+  Item *copy_or_same(THD* thd) 
+  {
+    return new Item_sum_count_distinct(thd, *this);
+  }
 };
 
 
@@ -257,8 +261,8 @@ class Item_sum_avg :public Item_sum_num
 
   public:
   Item_sum_avg(Item *item_par) :Item_sum_num(item_par),count(0) {}
-  Item_sum_avg(Item_sum_avg &item)
-    :Item_sum_num(item), sum(item.sum), count(item.count) {}
+  Item_sum_avg(THD *thd, Item_sum_avg &item)
+    :Item_sum_num(thd, item), sum(item.sum), count(item.count) {}
   enum Sumfunctype sum_func () const {return AVG_FUNC;}
   void reset();
   bool add();
@@ -268,7 +272,7 @@ class Item_sum_avg :public Item_sum_num
   Item *result_item(Field *field)
   { return new Item_avg_field(this); }
   const char *func_name() const { return "avg"; }
-  Item * get_same() { return new Item_sum_avg(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_avg(thd, *this); }
 };
 
 class Item_sum_variance;
@@ -309,8 +313,8 @@ class Item_sum_variance : public Item_sum_num
 
   public:
   Item_sum_variance(Item *item_par) :Item_sum_num(item_par),count(0) {}
-  Item_sum_variance(Item_sum_variance &item):
-    Item_sum_num(item), sum(item.sum), sum_sqr(item.sum_sqr),
+  Item_sum_variance(THD *thd, Item_sum_variance &item):
+    Item_sum_num(thd, item), sum(item.sum), sum_sqr(item.sum_sqr),
     count(item.count) {}
   enum Sumfunctype sum_func () const { return VARIANCE_FUNC; }
   void reset();
@@ -321,7 +325,7 @@ class Item_sum_variance : public Item_sum_num
   Item *result_item(Field *field)
   { return new Item_variance_field(this); }
   const char *func_name() const { return "variance"; }
-  Item * get_same() { return new Item_sum_variance(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_variance(thd, *this); }
 };
 
 class Item_sum_std;
@@ -366,8 +370,8 @@ class Item_sum_hybrid :public Item_sum
   Item_sum_hybrid(Item *item_par,int sign) :Item_sum(item_par),cmp_sign(sign),
     used_table_cache(~(table_map) 0)
   {}
-  Item_sum_hybrid(Item_sum_hybrid &item):
-    Item_sum(item), value(item.value), tmp_value(item.tmp_value),
+  Item_sum_hybrid(THD *thd, Item_sum_hybrid &item):
+    Item_sum(thd, item), value(item.value), tmp_value(item.tmp_value),
     sum(item.sum), sum_int(item.sum_int), hybrid_type(item.hybrid_type),
     cmp_sign(item.cmp_sign), used_table_cache(used_table_cache) {}
   bool fix_fields(THD *, TABLE_LIST *, Item **);
@@ -401,12 +405,12 @@ class Item_sum_min :public Item_sum_hybrid
 {
 public:
   Item_sum_min(Item *item_par) :Item_sum_hybrid(item_par,1) {}
-  Item_sum_min(Item_sum_min &item) :Item_sum_hybrid(item) {}
+  Item_sum_min(THD *thd, Item_sum_min &item) :Item_sum_hybrid(thd, item) {}
   enum Sumfunctype sum_func () const {return MIN_FUNC;}
 
   bool add();
   const char *func_name() const { return "min"; }
-  Item * get_same() { return new Item_sum_min(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_min(thd, *this); }
 };
 
 
@@ -414,12 +418,12 @@ class Item_sum_max :public Item_sum_hybrid
 {
 public:
   Item_sum_max(Item *item_par) :Item_sum_hybrid(item_par,-1) {}
-  Item_sum_max(Item_sum_max &item) :Item_sum_hybrid(item) {}
+  Item_sum_max(THD *thd, Item_sum_max &item) :Item_sum_hybrid(thd, item) {}
   enum Sumfunctype sum_func () const {return MAX_FUNC;}
 
   bool add();
   const char *func_name() const { return "max"; }
-  Item * get_same() { return new Item_sum_max(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_max(thd, *this); }
 };
 
 
@@ -431,8 +435,8 @@ class Item_sum_bit :public Item_sum_int
   public:
   Item_sum_bit(Item *item_par,ulonglong reset_arg)
     :Item_sum_int(item_par),reset_bits(reset_arg),bits(reset_arg) {}
-  Item_sum_bit(Item_sum_bit &item):
-    Item_sum_int(item), reset_bits(item.reset_bits), bits(item.bits) {}
+  Item_sum_bit(THD *thd, Item_sum_bit &item):
+    Item_sum_int(thd, item), reset_bits(item.reset_bits), bits(item.bits) {}
   enum Sumfunctype sum_func () const {return SUM_BIT_FUNC;}
   void reset();
   longlong val_int();
@@ -444,11 +448,11 @@ class Item_sum_or :public Item_sum_bit
 {
   public:
   Item_sum_or(Item *item_par) :Item_sum_bit(item_par,LL(0)) {}
-  Item_sum_or(Item_sum_or &item) :Item_sum_bit(item) {}
+  Item_sum_or(THD *thd, Item_sum_or &item) :Item_sum_bit(thd, item) {}
   bool add();
   void update_field(int offset);
   const char *func_name() const { return "bit_or"; }
-  Item * get_same() { return new Item_sum_or(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_or(thd, *this); }
 };
 
 
@@ -456,11 +460,11 @@ class Item_sum_and :public Item_sum_bit
 {
   public:
   Item_sum_and(Item *item_par) :Item_sum_bit(item_par, ~(ulonglong) LL(0)) {}
-  Item_sum_and(Item_sum_and &item) :Item_sum_bit(item) {}
+  Item_sum_and(THD *thd, Item_sum_and &item) :Item_sum_bit(thd, item) {}
   bool add();
   void update_field(int offset);
   const char *func_name() const { return "bit_and"; }
-  Item * get_same() { return new Item_sum_and(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_and(thd, *this); }
 };
 
 /*
@@ -478,7 +482,8 @@ public:
   Item_udf_sum( udf_func *udf_arg, List<Item> &list )
     :Item_sum( list ), udf(udf_arg)
   { quick_group=0;}
-  Item_udf_sum(Item_udf_sum &item) :Item_sum(item), udf(item.udf) {}
+  Item_udf_sum(THD *thd, Item_udf_sum &item)
+    :Item_sum(thd, item), udf(item.udf) {}
   ~Item_udf_sum() {}
   const char *func_name() const { return udf.name(); }
   bool fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
@@ -502,13 +507,14 @@ class Item_sum_udf_float :public Item_udf_sum
   Item_sum_udf_float(udf_func *udf_arg) :Item_udf_sum(udf_arg) {}
   Item_sum_udf_float(udf_func *udf_arg, List<Item> &list)
     :Item_udf_sum(udf_arg,list) {}
-  Item_sum_udf_float(Item_sum_udf_float &item): Item_udf_sum(item) {}
+  Item_sum_udf_float(THD *thd, Item_sum_udf_float &item)
+    :Item_udf_sum(thd, item) {}
   ~Item_sum_udf_float() {}
   longlong val_int() { return (longlong) Item_sum_udf_float::val(); }
   double val();
   String *val_str(String*str);
   void fix_length_and_dec() { fix_num_length_and_dec(); }
-  Item * get_same() { return new Item_sum_udf_float(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_udf_float(thd, *this); }
 };
 
 
@@ -518,14 +524,15 @@ public:
   Item_sum_udf_int(udf_func *udf_arg) :Item_udf_sum(udf_arg) {}
   Item_sum_udf_int(udf_func *udf_arg, List<Item> &list)
     :Item_udf_sum(udf_arg,list) {}
-  Item_sum_udf_int(Item_sum_udf_int &item): Item_udf_sum(item) {}
+  Item_sum_udf_int(THD *thd, Item_sum_udf_int &item)
+    :Item_udf_sum(thd, item) {}
   ~Item_sum_udf_int() {}
   longlong val_int();
   double val() { return (double) Item_sum_udf_int::val_int(); }
   String *val_str(String*str);
   enum Item_result result_type () const { return INT_RESULT; }
   void fix_length_and_dec() { decimals=0; max_length=21; }
-  Item * get_same() { return new Item_sum_udf_int(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_udf_int(thd, *this); }
 };
 
 
@@ -535,7 +542,8 @@ public:
   Item_sum_udf_str(udf_func *udf_arg) :Item_udf_sum(udf_arg) {}
   Item_sum_udf_str(udf_func *udf_arg, List<Item> &list)
     :Item_udf_sum(udf_arg,list) {}
-  Item_sum_udf_str(Item_sum_udf_str &item): Item_udf_sum(item) {}
+  Item_sum_udf_str(THD *thd, Item_sum_udf_str &item)
+    :Item_udf_sum(thd, item) {}
   ~Item_sum_udf_str() {}
   String *val_str(String *);
   double val()
@@ -553,7 +561,7 @@ public:
   }
   enum Item_result result_type () const { return STRING_RESULT; }
   void fix_length_and_dec();
-  Item * get_same() { return new Item_sum_udf_str(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_udf_str(thd, *this); }
 };
 
 #else /* Dummy functions to get sql_yacc.cc compiled */
@@ -563,14 +571,15 @@ class Item_sum_udf_float :public Item_sum_num
  public:
   Item_sum_udf_float(udf_func *udf_arg) :Item_sum_num() {}
   Item_sum_udf_float(udf_func *udf_arg, List<Item> &list) :Item_sum_num() {}
-  Item_sum_udf_float(Item_sum_udf_float &item): Item_sum_num(item) {}
+  Item_sum_udf_float(THD *thd, Item_sum_udf_float &item)
+    :Item_sum_num(thd, item) {}
   ~Item_sum_udf_float() {}
   enum Sumfunctype sum_func () const { return UDF_SUM_FUNC; }
   double val() { return 0.0; }
   void reset() {}
   bool add() { return 0; }  
   void update_field(int offset) {}
-  Item * get_same() { return new Item_sum_udf_float(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_udf_float(thd, *this); }
 };
 
 
@@ -579,7 +588,8 @@ class Item_sum_udf_int :public Item_sum_num
 public:
   Item_sum_udf_int(udf_func *udf_arg) :Item_sum_num() {}
   Item_sum_udf_int(udf_func *udf_arg, List<Item> &list) :Item_sum_num() {}
-  Item_sum_udf_int(Item_sum_udf_int &item): Item_sum_num(item) {}
+  Item_sum_udf_int(THD *thd, Item_sum_udf_int &item)
+    :Item_sum_num(thd, item) {}
   ~Item_sum_udf_int() {}
   enum Sumfunctype sum_func () const { return UDF_SUM_FUNC; }
   longlong val_int() { return 0; }
@@ -587,7 +597,7 @@ public:
   void reset() {}
   bool add() { return 0; }  
   void update_field(int offset) {}
-  Item * get_same() { return new Item_sum_udf_int(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_udf_int(thd, *this); }
 };
 
 
@@ -596,7 +606,8 @@ class Item_sum_udf_str :public Item_sum_num
 public:
   Item_sum_udf_str(udf_func *udf_arg) :Item_sum_num() {}
   Item_sum_udf_str(udf_func *udf_arg, List<Item> &list)  :Item_sum_num() {}
-  Item_sum_udf_str(Item_sum_udf_str &item): Item_sum_num(item) {}
+  Item_sum_udf_str(THD *thd, Item_sum_udf_str &item)
+    :Item_sum_num(thd, item) {}
   ~Item_sum_udf_str() {}
   String *val_str(String *) { null_value=1; return 0; }
   double val() { null_value=1; return 0.0; }
@@ -607,7 +618,7 @@ public:
   void reset() {}
   bool add() { return 0; }  
   void update_field(int offset) {}
-  Item * get_same() { return new Item_sum_udf_str(*this); }
+  Item *copy_or_same(THD* thd) { return new Item_sum_udf_str(thd, *this); }
 };
 
 #endif /* HAVE_DLOPEN */
diff --git a/sql/item_uniq.h b/sql/item_uniq.h
index 9098dfe7d41..ac004e747f8 100644
--- a/sql/item_uniq.h
+++ b/sql/item_uniq.h
@@ -37,7 +37,8 @@ class Item_sum_unique_users :public Item_sum_num
 public:
   Item_sum_unique_users(Item *name_arg,int start,int end,Item *item_arg)
     :Item_sum_num(item_arg) {}
-  Item_sum_unique_users(Item_sum_unique_users &item): Item_sum_num(item) {}
+  Item_sum_unique_users(THD *thd, Item_sum_unique_users &item)
+    :Item_sum_num(thd, item) {}
   double val() { return 0.0; }  
   enum Sumfunctype sum_func () const {return UNIQUE_USERS_FUNC;}
   void reset() {}
@@ -49,5 +50,8 @@ public:
     fixed= 1;
     return 0;
   }
-  Item_sum * get_same() { return new Item_sum_unique_users(*this); }
+  Item_sum *copy_or_same(THD* thd)
+  {
+    return new Item_sum_unique_users(thd, *this);
+  }
 };
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 6bbec63c258..7b7f3042469 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -1845,10 +1845,8 @@ find_item_in_list(Item *find, List<Item> &items, uint *counter,
     table_name= ((Item_ident*) find)->table_name;
   }
 
-  uint i= 0;
-  while ((item=li++))
+  for (uint i= 0; (item=li++); i++)
   {
-    i++;
     if (field_name && item->type() == Item::FIELD_ITEM)
     {
       if (!my_strcasecmp(system_charset_info,
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index fa966a00c2f..194470c8eda 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -140,7 +140,7 @@ static void calc_group_buffer(JOIN *join,ORDER *group);
 static bool alloc_group_fields(JOIN *join,ORDER *group);
 static bool make_sum_func_list(JOIN *join,List<Item> &fields);
 // Create list for using with tempory table
-static bool change_to_use_tmp_fields(Item **ref_pointer_array,
+static bool change_to_use_tmp_fields(THD *thd, Item **ref_pointer_array,
 				     List<Item> &new_list1,
 				     List<Item> &new_list2,
 				     uint elements, List<Item> &items);
@@ -968,7 +968,7 @@ JOIN::exec()
       items1= items0 + all_fields.elements;
       if (sort_and_group || curr_tmp_table->group)
       {
-	if (change_to_use_tmp_fields(items1,
+	if (change_to_use_tmp_fields(thd, items1,
 				     tmp_fields_list1, tmp_all_fields1,
 				     fields_list.elements, all_fields))
 	  DBUG_VOID_RETURN;
@@ -1088,7 +1088,7 @@ JOIN::exec()
       if (!items2)
       {
 	items2= items1 + all_fields.elements;
-	if (change_to_use_tmp_fields(items2,
+	if (change_to_use_tmp_fields(thd, items2,
 				     tmp_fields_list2, tmp_all_fields2, 
 				     fields_list.elements, tmp_all_fields1))
 	  DBUG_VOID_RETURN;
@@ -7069,12 +7069,12 @@ find_order_in_list(THD *thd, Item **ref_pointer_array,
     order->in_field_list= 1;
     return 0;
   }
-  uint counter= 0;
+  uint counter;
   Item **item= find_item_in_list(*order->item, fields, &counter,
 				 IGNORE_ERRORS);
   if (item)
   {
-    order->item= ref_pointer_array + counter-1;
+    order->item= ref_pointer_array + counter;
     order->in_field_list=1;
     return 0;
   }
@@ -7192,7 +7192,7 @@ setup_new_fields(THD *thd,TABLE_LIST *tables,List<Item> &fields,
   DBUG_ENTER("setup_new_fields");
 
   thd->set_query_id=1;				// Not really needed, but...
-  uint counter= 0;
+  uint counter;
   for (; new_field ; new_field= new_field->next)
   {
     if ((item= find_item_in_list(*new_field->item, fields, &counter,
@@ -7471,7 +7471,7 @@ setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
     if (pos->type() == Item::FIELD_ITEM)
     {
       Item_field *item;
-      if (!(item= new Item_field(*((Item_field*) pos))))
+      if (!(item= new Item_field(thd, *((Item_field*) pos))))
 	goto err;
       pos= item;
       if (item->field->flags & BLOB_FLAG)
@@ -7590,7 +7590,7 @@ make_sum_func_list(JOIN *join,List<Item> &fields)
 */
 
 static bool
-change_to_use_tmp_fields(Item **ref_pointer_array,
+change_to_use_tmp_fields(THD *thd, Item **ref_pointer_array,
 			 List<Item> &new_list1, List<Item> &new_list2,
 			 uint elements, List<Item> &items)
 {
@@ -7609,7 +7609,7 @@ change_to_use_tmp_fields(Item **ref_pointer_array,
     else
       if (item->type() == Item::FIELD_ITEM)
       {
-	item_field= item->get_tmp_table_item();
+	item_field= item->get_tmp_table_item(thd);
       }
       else if ((field= item->tmp_table_field()))
       {
@@ -7665,7 +7665,7 @@ change_refs_to_tmp_fields(THD *thd, Item **ref_pointer_array,
   uint i, border= items.elements - elements;
   for (i= 0; (item= it++); i++)
   {
-    new_list2.push_back(new_item= item->get_tmp_table_item());
+    new_list2.push_back(new_item= item->get_tmp_table_item(thd));
     ref_pointer_array[((i < border)? items.elements-i-1 : i-border)]=
       new_item;
   }