Merge bk@192.168.21.1:mysql-5.0-opt

into  mysql.com:/home/hf/work/mysql-5.0-0mrg


BitKeeper/deleted/.del-mysql_client.test:
  Auto merged
include/mysql.h:
  Auto merged
libmysqld/lib_sql.cc:
  Auto merged
mysql-test/r/order_by.result:
  Auto merged
mysql-test/r/query_cache.result:
  Auto merged
mysql-test/r/subselect.result:
  Auto merged
mysql-test/r/type_newdecimal.result:
  Auto merged
mysql-test/t/flush.test:
  Auto merged
mysql-test/t/flush_block_commit.test:
  Auto merged
mysql-test/t/innodb-deadlock.test:
  Auto merged
mysql-test/t/innodb-lock.test:
  Auto merged
mysql-test/t/lock_multi.test:
  Auto merged
mysql-test/t/mysql.test:
  Auto merged
mysql-test/t/query_cache.test:
  Auto merged
mysql-test/t/rename.test:
  Auto merged
mysql-test/t/show_check.test:
  Auto merged
mysql-test/t/status.test:
  Auto merged
mysql-test/t/subselect.test:
  Auto merged
mysql-test/t/type_newdecimal.test:
  Auto merged
sql/field.cc:
  Auto merged
sql/field.h:
  Auto merged
sql/handler.cc:
  Auto merged
sql/item.cc:
  Auto merged
sql/item.h:
  Auto merged
sql/item_func.cc:
  Auto merged
sql/item_func.h:
  Auto merged
sql/item_subselect.cc:
  Auto merged
sql/item_subselect.h:
  Auto merged
sql/item_sum.cc:
  Auto merged
sql/item_sum.h:
  Auto merged
sql/item_timefunc.cc:
  Auto merged
sql/item_timefunc.h:
  Auto merged
sql/mysql_priv.h:
  Auto merged
sql/protocol.cc:
  Auto merged
sql/protocol.h:
  Auto merged
sql/sql_base.cc:
  Auto merged
sql/sql_class.h:
  Auto merged
sql/sql_lex.cc:
  Auto merged
sql/sql_lex.h:
  Auto merged
sql/sql_parse.cc:
  Auto merged
sql/sql_select.cc:
  Auto merged
sql/sql_show.cc:
  Auto merged
sql/sql_table.cc:
  Auto merged
sql/sql_yacc.yy:
  Auto merged
sql/table.cc:
  Auto merged
sql-common/client.c:
  Auto merged
sql-common/my_time.c:
  Auto merged
Makefile.am:
  merging
client/mysqltest.c:
  merging
include/my_time.h:
  merging
libmysql/libmysql.c:
  merging
mysql-test/t/order_by.test:
  merging

31 files changed, 1107 insertions, 208 deletions

diff --git a/sql/field.cc b/sql/field.cc
index f04efc66dfd..1cfd0843179 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -2426,6 +2426,13 @@ int Field_new_decimal::store_decimal(const my_decimal *decimal_value)
 }
 
 
+int Field_new_decimal::store_time(TIME *ltime, timestamp_type t_type)
+{
+    my_decimal decimal_value;
+    return store_value(date2my_decimal(ltime, &decimal_value));
+}
+
+
 double Field_new_decimal::val_real(void)
 {
   double dbl;
@@ -5400,7 +5407,21 @@ int Field_newdate::store_time(TIME *ltime,timestamp_type type)
   long tmp;
   int error= 0;
   if (type == MYSQL_TIMESTAMP_DATE || type == MYSQL_TIMESTAMP_DATETIME)
+  {
     tmp=ltime->year*16*32+ltime->month*32+ltime->day;
+    if ((my_bool)check_date(ltime, tmp,
+                            (TIME_FUZZY_DATE |
+                             (current_thd->variables.sql_mode &
+                              (MODE_NO_ZERO_IN_DATE | MODE_NO_ZERO_DATE |
+                               MODE_INVALID_DATES))), &error))
+    {
+      char buff[12];
+      String str(buff, sizeof(buff), &my_charset_latin1);
+      make_date((DATE_TIME_FORMAT *) 0, ltime, &str);
+      set_datetime_warning(MYSQL_ERROR::WARN_LEVEL_WARN, WARN_DATA_TRUNCATED,
+                           str.ptr(), str.length(), MYSQL_TIMESTAMP_DATE, 1);
+    }
+  }
   else
   {
     tmp=0;
@@ -5609,8 +5630,22 @@ int Field_datetime::store_time(TIME *ltime,timestamp_type type)
     structure always fit into DATETIME range.
   */
   if (type == MYSQL_TIMESTAMP_DATE || type == MYSQL_TIMESTAMP_DATETIME)
+  {
     tmp=((ltime->year*10000L+ltime->month*100+ltime->day)*LL(1000000)+
 	 (ltime->hour*10000L+ltime->minute*100+ltime->second));
+    if ((my_bool)check_date(ltime, tmp,
+                            (TIME_FUZZY_DATE |
+                             (current_thd->variables.sql_mode &
+                              (MODE_NO_ZERO_IN_DATE | MODE_NO_ZERO_DATE |
+                               MODE_INVALID_DATES))), &error))
+    {
+      char buff[19];
+      String str(buff, sizeof(buff), &my_charset_latin1);
+      make_datetime((DATE_TIME_FORMAT *) 0, ltime, &str);
+      set_datetime_warning(MYSQL_ERROR::WARN_LEVEL_WARN, WARN_DATA_TRUNCATED,
+                           str.ptr(), str.length(), MYSQL_TIMESTAMP_DATETIME,1);
+    }
+  }
   else
   {
     tmp=0;
diff --git a/sql/field.h b/sql/field.h
index 0f845f6c2f9..709630218b2 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -496,6 +496,7 @@ public:
   int  store(const char *to, uint length, CHARSET_INFO *charset);
   int  store(double nr);
   int  store(longlong nr, bool unsigned_val);
+  int store_time(TIME *ltime, timestamp_type t_type);
   int  store_decimal(const my_decimal *);
   double val_real(void);
   longlong val_int(void);
diff --git a/sql/filesort.cc b/sql/filesort.cc
index b063b416191..12b17846fe4 100644
--- a/sql/filesort.cc
+++ b/sql/filesort.cc
@@ -109,6 +109,8 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
   DBUG_PUSH("");		/* No DBUG here */
 #endif
   FILESORT_INFO table_sort;
+  TABLE_LIST *tab= table->pos_in_table_list;
+  Item_subselect *subselect= tab ? tab->containing_subselect() : 0;
   /* 
     Don't use table->sort in filesort as it is also used by 
     QUICK_INDEX_MERGE_SELECT. Work with a copy and put it back at the end 
@@ -121,7 +123,6 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
   my_b_clear(&tempfile);
   my_b_clear(&buffpek_pointers);
   buffpek=0;
-  sort_keys= (uchar **) NULL;
   error= 1;
   bzero((char*) &param,sizeof(param));
   param.sort_length= sortlength(thd, sortorder, s_length, &multi_byte_charset);
@@ -202,13 +203,15 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
     ulong old_memavl;
     ulong keys= memavl/(param.rec_length+sizeof(char*));
     param.keys=(uint) min(records+1, keys);
-    if ((sort_keys= (uchar **) make_char_array(param.keys, param.rec_length,
-					       MYF(0))))
+    if (table_sort.sort_keys ||
+        (table_sort.sort_keys= (uchar **) make_char_array(param.keys, param.rec_length,
+                                               MYF(0))))
       break;
     old_memavl=memavl;
     if ((memavl=memavl/4*3) < min_sort_memory && old_memavl > min_sort_memory)
       memavl= min_sort_memory;
   }
+  sort_keys= table_sort.sort_keys;
   if (memavl < min_sort_memory)
   {
     my_error(ER_OUTOFMEMORY,MYF(ME_ERROR+ME_WAITTANG),
@@ -235,8 +238,12 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
   }
   else
   {
-    if (!(buffpek=read_buffpek_from_file(&buffpek_pointers, maxbuffer)))
+    if (!table_sort.buffpek && table_sort.buffpek_len < maxbuffer &&
+        !(table_sort.buffpek=
+          (byte *) read_buffpek_from_file(&buffpek_pointers, maxbuffer)))
       goto err;
+    buffpek= (BUFFPEK *) table_sort.buffpek;
+    table_sort.buffpek_len= maxbuffer;
     close_cached_file(&buffpek_pointers);
 	/* Open cached file if it isn't open */
     if (! my_b_inited(outfile) &&
@@ -269,8 +276,14 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
  err:
   if (param.tmp_buffer)
     x_free(param.tmp_buffer);
-  x_free((gptr) sort_keys);
-  x_free((gptr) buffpek);
+  if (!subselect || !subselect->is_uncacheable())
+  {
+    x_free((gptr) sort_keys);
+    table_sort.sort_keys= 0;
+    x_free((gptr) buffpek);
+    table_sort.buffpek= 0;
+    table_sort.buffpek_len= 0;
+  }
   close_cached_file(&tempfile);
   close_cached_file(&buffpek_pointers);
   if (my_b_inited(outfile))
@@ -301,13 +314,27 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
 } /* filesort */
 
 
-void filesort_free_buffers(TABLE *table)
+void filesort_free_buffers(TABLE *table, bool full)
 {
   if (table->sort.record_pointers)
   {
     my_free((gptr) table->sort.record_pointers,MYF(0));
     table->sort.record_pointers=0;
   }
+  if (full)
+  {
+    if (table->sort.sort_keys )
+    {
+      x_free((gptr) table->sort.sort_keys);
+      table->sort.sort_keys= 0;
+    }
+    if (table->sort.buffpek)
+    {
+      x_free((gptr) table->sort.buffpek);
+      table->sort.buffpek= 0;
+      table->sort.buffpek_len= 0;
+    }
+  }
   if (table->sort.addon_buf)
   {
     my_free((char *) table->sort.addon_buf, MYF(0));
diff --git a/sql/handler.cc b/sql/handler.cc
index cff8213edec..040d1b0c279 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -1798,8 +1798,8 @@ void handler::print_error(int error, myf errflag)
     break;
   }
   case HA_ERR_NULL_IN_SPATIAL:
-    textno= ER_UNKNOWN_ERROR;
-    break;
+    my_error(ER_CANT_CREATE_GEOMETRY_OBJECT, MYF(0));
+    DBUG_VOID_RETURN;
   case HA_ERR_FOUND_DUPP_UNIQUE:
     textno=ER_DUP_UNIQUE;
     break;
diff --git a/sql/item.cc b/sql/item.cc
index 3864ee966c4..59d28c00416 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -272,6 +272,34 @@ my_decimal *Item::val_decimal_from_string(my_decimal *decimal_value)
 }
 
 
+my_decimal *Item::val_decimal_from_date(my_decimal *decimal_value)
+{
+  DBUG_ASSERT(fixed == 1);
+  TIME ltime;
+  longlong date;
+  if (get_date(&ltime, TIME_FUZZY_DATE))
+  {
+    my_decimal_set_zero(decimal_value);
+    return 0;
+  }
+  return date2my_decimal(&ltime, decimal_value);
+}
+
+
+my_decimal *Item::val_decimal_from_time(my_decimal *decimal_value)
+{
+  DBUG_ASSERT(fixed == 1);
+  TIME ltime;
+  longlong date;
+  if (get_time(&ltime))
+  {
+    my_decimal_set_zero(decimal_value);
+    return 0;
+  }
+  return date2my_decimal(&ltime, decimal_value);
+}
+
+
 double Item::val_real_from_decimal()
 {
   /* Note that fix_fields may not be called for Item_avg_field items */
@@ -295,6 +323,25 @@ longlong Item::val_int_from_decimal()
   return result;
 }
 
+int Item::save_time_in_field(Field *field)
+{
+  TIME ltime;
+  if (get_time(&ltime))
+    return set_field_to_null(field);
+  field->set_notnull();
+  return field->store_time(&ltime, MYSQL_TIMESTAMP_TIME);
+}
+
+
+int Item::save_date_in_field(Field *field)
+{
+  TIME ltime;
+  if (get_date(&ltime, TIME_FUZZY_DATE))
+    return set_field_to_null(field);
+  field->set_notnull();
+  return field->store_time(&ltime, MYSQL_TIMESTAMP_DATETIME);
+}
+
 
 Item::Item():
   rsize(0), name(0), orig_name(0), name_length(0), fixed(0),
@@ -1148,6 +1195,28 @@ void Item_name_const::print(String *str)
 
 
 /*
+ need a special class to adjust printing : references to aggregate functions 
+ must not be printed as refs because the aggregate functions that are added to
+ the front of select list are not printed as well.
+*/
+class Item_aggregate_ref : public Item_ref
+{
+public:
+  Item_aggregate_ref(Name_resolution_context *context_arg, Item **item,
+                  const char *table_name_arg, const char *field_name_arg)
+    :Item_ref(context_arg, item, table_name_arg, field_name_arg) {}
+
+  void print (String *str)
+  {
+    if (ref)
+      (*ref)->print(str);
+    else
+      Item_ident::print(str);
+  }
+};
+
+
+/*
   Move SUM items out from item tree and replace with reference
 
   SYNOPSIS
@@ -1200,8 +1269,8 @@ void Item::split_sum_func2(THD *thd, Item **ref_pointer_array,
     Item *new_item, *real_itm= real_item();
 
     ref_pointer_array[el]= real_itm;
-    if (!(new_item= new Item_ref(&thd->lex->current_select->context,
-                                 ref_pointer_array + el, 0, name)))
+    if (!(new_item= new Item_aggregate_ref(&thd->lex->current_select->context,
+                                           ref_pointer_array + el, 0, name)))
       return;                                   // fatal_error is set
     fields.push_front(real_itm);
     thd->change_item_tree(ref, new_item);
@@ -3658,16 +3727,16 @@ bool Item_field::fix_fields(THD *thd, Item **reference)
               Item_ref to point to the Item in the select list and replace the
               Item_field created by the parser with the new Item_ref.
             */
-            Item_ref *rf= new Item_ref(db_name,table_name,field_name);
+            Item_ref *rf= new Item_ref(context, db_name,table_name,field_name);
             if (!rf)
               return 1;
-            thd->change_item_tree(ref, rf);
+            thd->change_item_tree(reference, rf);
             /*
               Because Item_ref never substitutes itself with other items 
               in Item_ref::fix_fields(), we can safely use the original 
               pointer to it even after fix_fields()
              */
-            return rf->fix_fields(thd, tables, ref) ||  rf->check_cols(1);
+            return rf->fix_fields(thd, reference) ||  rf->check_cols(1);
           }
         }
       }
@@ -4133,6 +4202,10 @@ void Item_field::make_field(Send_field *tmp_field)
   DBUG_ASSERT(tmp_field->table_name != 0);
   if (name)
     tmp_field->col_name=name;			// Use user supplied name
+  if (table_name)
+    tmp_field->table_name= table_name;
+  if (db_name)
+    tmp_field->db_name= db_name;
 }
 
 
diff --git a/sql/item.h b/sql/item.h
index b5490f9e814..63d89113ec1 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -605,9 +605,14 @@ public:
   my_decimal *val_decimal_from_real(my_decimal *decimal_value);
   my_decimal *val_decimal_from_int(my_decimal *decimal_value);
   my_decimal *val_decimal_from_string(my_decimal *decimal_value);
+  my_decimal *val_decimal_from_date(my_decimal *decimal_value);
+  my_decimal *val_decimal_from_time(my_decimal *decimal_value);
   longlong val_int_from_decimal();
   double val_real_from_decimal();
 
+  int save_time_in_field(Field *field);
+  int save_date_in_field(Field *field);
+
   virtual Field *get_tmp_table_field() { return 0; }
   /* This is also used to create fields in CREATE ... SELECT: */
   virtual Field *tmp_table_field(TABLE *t_arg) { return 0; }
@@ -1947,6 +1952,16 @@ public:
 
 class Item_in_subselect;
 
+
+/*
+  An object of this class:
+   - Converts val_XXX() calls to ref->val_XXX_result() calls, like Item_ref.
+   - Sets owner->was_null=TRUE if it has returned a NULL value from any
+     val_XXX() function. This allows to inject an Item_ref_null_helper
+     object into subquery and then check if the subquery has produced a row
+     with NULL value.
+*/
+
 class Item_ref_null_helper: public Item_ref
 {
 protected:
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 9a400d60ae6..540f67ba0ee 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -786,9 +786,41 @@ longlong Item_in_optimizer::val_int()
 {
   DBUG_ASSERT(fixed == 1);
   cache->store(args[0]);
+  
   if (cache->null_value)
   {
-    null_value= 1;
+    if (((Item_in_subselect*)args[1])->is_top_level_item())
+    {
+      /*
+        We're evaluating "NULL IN (SELECT ...)". The result can be NULL or
+        FALSE, and we can return one instead of another. Just return NULL.
+      */
+      null_value= 1;
+    }
+    else
+    {
+      if (!((Item_in_subselect*)args[1])->is_correlated &&
+          result_for_null_param != UNKNOWN)
+      {
+        /* Use cached value from previous execution */
+        null_value= result_for_null_param;
+      }
+      else
+      {
+        /*
+          We're evaluating "NULL IN (SELECT ...)". The result is:
+             FALSE if SELECT produces an empty set, or
+             NULL  otherwise.
+          We disable the predicates we've pushed down into subselect, run the
+          subselect and see if it has produced any rows.
+        */
+        ((Item_in_subselect*)args[1])->enable_pushed_conds= FALSE;
+        longlong tmp= args[1]->val_bool_result();
+        result_for_null_param= null_value= 
+          !((Item_in_subselect*)args[1])->engine->no_rows();
+        ((Item_in_subselect*)args[1])->enable_pushed_conds= TRUE;
+      }
+    }
     return 0;
   }
   bool tmp= args[1]->val_bool_result();
diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h
index c8439cba303..acad1e51bc9 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -100,25 +100,44 @@ public:
 };
 
 class Item_cache;
+#define UNKNOWN ((my_bool)-1)
+
+
+/*
+  Item_in_optimizer(left_expr, Item_in_subselect(...))
+
+  Item_in_optimizer is used to wrap an instance of Item_in_subselect. This
+  class does the following:
+   - Evaluate the left expression and store it in Item_cache_* object (to
+     avoid re-evaluating it many times during subquery execution)
+   - Shortcut the evaluation of "NULL IN (...)" to NULL in the cases where we
+     don't care if the result is NULL or FALSE.
+
+  NOTE
+    It is not quite clear why the above listed functionality should be
+    placed into a separate class called 'Item_in_optimizer'.
+*/
+
 class Item_in_optimizer: public Item_bool_func
 {
 protected:
   Item_cache *cache;
   bool save_cache;
+  /* 
+    Stores the value of "NULL IN (SELECT ...)" for uncorrelated subqueries:
+      UNKNOWN - "NULL in (SELECT ...)" has not yet been evaluated
+      FALSE   - result is FALSE
+      TRUE    - result is NULL
+  */
+  my_bool result_for_null_param;
 public:
   Item_in_optimizer(Item *a, Item_in_subselect *b):
-    Item_bool_func(a, my_reinterpret_cast(Item *)(b)), cache(0), save_cache(0)
+    Item_bool_func(a, my_reinterpret_cast(Item *)(b)), cache(0),
+    save_cache(0), result_for_null_param(UNKNOWN)
   {}
   bool fix_fields(THD *, Item **);
   bool fix_left(THD *thd, Item **ref);
   bool is_null();
-  /*
-    Item_in_optimizer item is special boolean function. On value request 
-    (one of val, val_int or val_str methods) it evaluate left expression 
-    of IN by storing it value in cache item (one of Item_cache* items), 
-    then it test cache is it NULL. If left expression (cache) is NULL then
-    Item_in_optimizer return NULL, else it evaluate Item_in_subselect.
-  */
   longlong val_int();
   void cleanup();
   const char *func_name() const { return "<in_optimizer>"; }
@@ -256,9 +275,11 @@ public:
 class Item_maxmin_subselect;
 
 /*
+  trigcond<param>(arg) ::= param? arg : TRUE
+
   The class Item_func_trig_cond is used for guarded predicates 
   which are employed only for internal purposes.
-  A guarded predicates is an object consisting of an a regular or
+  A guarded predicate is an object consisting of an a regular or
   a guarded predicate P and a pointer to a boolean guard variable g. 
   A guarded predicate P/g is evaluated to true if the value of the
   guard g is false, otherwise it is evaluated to the same value that
@@ -276,6 +297,10 @@ class Item_maxmin_subselect;
   Objects of this class are built only for query execution after
   the execution plan has been already selected. That's why this
   class needs only val_int out of generic methods. 
+ 
+  Current uses of Item_func_trig_cond objects:
+   - To wrap selection conditions when executing outer joins
+   - To wrap condition that is pushed down into subquery
 */
 
 class Item_func_trig_cond: public Item_bool_func
@@ -1019,6 +1044,11 @@ public:
 /* Functions used by HAVING for rewriting IN subquery */
 
 class Item_in_subselect;
+
+/* 
+  This is like IS NOT NULL but it also remembers if it ever has
+  encountered a NULL.
+*/
 class Item_is_not_null_test :public Item_func_isnull
 {
   Item_in_subselect* owner;
diff --git a/sql/item_func.cc b/sql/item_func.cc
index fa953889619..0fc6e5f6c61 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -964,7 +964,14 @@ longlong Item_func_unsigned::val_int()
   longlong value;
   int error;
 
-  if (args[0]->cast_to_int_type() != STRING_RESULT)
+  if (args[0]->cast_to_int_type() == DECIMAL_RESULT)
+  {
+    my_decimal tmp, *dec= args[0]->val_decimal(&tmp);
+    if (!(null_value= args[0]->null_value))
+      my_decimal2int(E_DEC_FATAL_ERROR, dec, 1, &value);
+    return value;
+  }
+  else if (args[0]->cast_to_int_type() != STRING_RESULT)
   {
     value= args[0]->val_int();
     null_value= args[0]->null_value; 
@@ -2882,6 +2889,20 @@ void Item_udf_func::cleanup()
 }
 
 
+void Item_udf_func::print(String *str)
+{
+  str->append(func_name());
+  str->append('(');
+  for (uint i=0 ; i < arg_count ; i++)
+  {
+    if (i != 0)
+      str->append(',');
+    args[i]->print_item_w_name(str);
+  }
+  str->append(')');
+}
+
+
 double Item_func_udf_float::val_real()
 {
   DBUG_ASSERT(fixed == 1);
diff --git a/sql/item_func.h b/sql/item_func.h
index f887ba6a7cd..9d94bc85d2c 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -953,6 +953,7 @@ public:
   Item_result result_type () const { return udf.result_type(); }
   table_map not_null_tables() const { return 0; }
   bool is_expensive() { return 1; }
+  void print(String *str);
 };
 
 
diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index 5251bb91a70..d2f8e092d00 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -37,7 +37,7 @@ inline Item * and_items(Item* cond, Item *item)
 Item_subselect::Item_subselect():
   Item_result_field(), value_assigned(0), thd(0), substitution(0),
   engine(0), old_engine(0), used_tables_cache(0), have_to_be_excluded(0),
-  const_item_cache(1), engine_changed(0), changed(0)
+  const_item_cache(1), engine_changed(0), changed(0), is_correlated(FALSE)
 {
   with_subselect= 1;
   reset();
@@ -192,16 +192,16 @@ bool Item_subselect::fix_fields(THD *thd_param, Item **ref)
   return res;
 }
 
-bool Item_subselect::exec()
+bool Item_subselect::exec(bool full_scan)
 {
   int res;
 
-  res= engine->exec();
+  res= engine->exec(full_scan);
 
   if (engine_changed)
   {
     engine_changed= 0;
-    return exec();
+    return exec(full_scan);
   }
   return (res);
 }
@@ -450,13 +450,13 @@ bool Item_singlerow_subselect::null_inside()
 
 void Item_singlerow_subselect::bring_value()
 {
-  exec();
+  exec(FALSE);
 }
 
 double Item_singlerow_subselect::val_real()
 {
   DBUG_ASSERT(fixed == 1);
-  if (!exec() && !value->null_value)
+  if (!exec(FALSE) && !value->null_value)
   {
     null_value= 0;
     return value->val_real();
@@ -471,7 +471,7 @@ double Item_singlerow_subselect::val_real()
 longlong Item_singlerow_subselect::val_int()
 {
   DBUG_ASSERT(fixed == 1);
-  if (!exec() && !value->null_value)
+  if (!exec(FALSE) && !value->null_value)
   {
     null_value= 0;
     return value->val_int();
@@ -485,7 +485,7 @@ longlong Item_singlerow_subselect::val_int()
 
 String *Item_singlerow_subselect::val_str(String *str)
 {
-  if (!exec() && !value->null_value)
+  if (!exec(FALSE) && !value->null_value)
   {
     null_value= 0;
     return value->val_str(str);
@@ -500,7 +500,7 @@ String *Item_singlerow_subselect::val_str(String *str)
 
 my_decimal *Item_singlerow_subselect::val_decimal(my_decimal *decimal_value)
 {
-  if (!exec() && !value->null_value)
+  if (!exec(FALSE) && !value->null_value)
   {
     null_value= 0;
     return value->val_decimal(decimal_value);
@@ -515,7 +515,7 @@ my_decimal *Item_singlerow_subselect::val_decimal(my_decimal *decimal_value)
 
 bool Item_singlerow_subselect::val_bool()
 {
-  if (!exec() && !value->null_value)
+  if (!exec(FALSE) && !value->null_value)
   {
     null_value= 0;
     return value->val_bool();
@@ -566,7 +566,8 @@ bool Item_in_subselect::test_limit(SELECT_LEX_UNIT *unit)
 
 Item_in_subselect::Item_in_subselect(Item * left_exp,
 				     st_select_lex *select_lex):
-  Item_exists_subselect(), optimizer(0), transformed(0), upper_item(0)
+  Item_exists_subselect(), optimizer(0), transformed(0),
+  enable_pushed_conds(TRUE), upper_item(0)
 {
   DBUG_ENTER("Item_in_subselect::Item_in_subselect");
   left_expr= left_exp;
@@ -611,7 +612,7 @@ void Item_exists_subselect::fix_length_and_dec()
 double Item_exists_subselect::val_real()
 {
   DBUG_ASSERT(fixed == 1);
-  if (exec())
+  if (exec(FALSE))
   {
     reset();
     return 0;
@@ -622,7 +623,7 @@ double Item_exists_subselect::val_real()
 longlong Item_exists_subselect::val_int()
 {
   DBUG_ASSERT(fixed == 1);
-  if (exec())
+  if (exec(FALSE))
   {
     reset();
     return 0;
@@ -633,7 +634,7 @@ longlong Item_exists_subselect::val_int()
 String *Item_exists_subselect::val_str(String *str)
 {
   DBUG_ASSERT(fixed == 1);
-  if (exec())
+  if (exec(FALSE))
   {
     reset();
     return 0;
@@ -646,7 +647,7 @@ String *Item_exists_subselect::val_str(String *str)
 my_decimal *Item_exists_subselect::val_decimal(my_decimal *decimal_value)
 {
   DBUG_ASSERT(fixed == 1);
-  if (exec())
+  if (exec(FALSE))
   {
     reset();
     return 0;
@@ -659,7 +660,7 @@ my_decimal *Item_exists_subselect::val_decimal(my_decimal *decimal_value)
 bool Item_exists_subselect::val_bool()
 {
   DBUG_ASSERT(fixed == 1);
-  if (exec())
+  if (exec(FALSE))
   {
     reset();
     return 0;
@@ -677,7 +678,7 @@ double Item_in_subselect::val_real()
   DBUG_ASSERT(0);
   DBUG_ASSERT(fixed == 1);
   null_value= 0;
-  if (exec())
+  if (exec(!enable_pushed_conds))
   {
     reset();
     null_value= 1;
@@ -698,7 +699,7 @@ longlong Item_in_subselect::val_int()
   DBUG_ASSERT(0);
   DBUG_ASSERT(fixed == 1);
   null_value= 0;
-  if (exec())
+  if (exec(!enable_pushed_conds))
   {
     reset();
     null_value= 1;
@@ -719,7 +720,7 @@ String *Item_in_subselect::val_str(String *str)
   DBUG_ASSERT(0);
   DBUG_ASSERT(fixed == 1);
   null_value= 0;
-  if (exec())
+  if (exec(!enable_pushed_conds))
   {
     reset();
     null_value= 1;
@@ -738,7 +739,8 @@ String *Item_in_subselect::val_str(String *str)
 bool Item_in_subselect::val_bool()
 {
   DBUG_ASSERT(fixed == 1);
-  if (exec())
+  null_value= 0;
+  if (exec(!enable_pushed_conds))
   {
     reset();
     null_value= 1;
@@ -756,8 +758,9 @@ my_decimal *Item_in_subselect::val_decimal(my_decimal *decimal_value)
     method should not be used
   */
   DBUG_ASSERT(0);
+  null_value= 0;
   DBUG_ASSERT(fixed == 1);
-  if (exec())
+  if (exec(!enable_pushed_conds))
   {
     reset();
     null_value= 1;
@@ -770,7 +773,55 @@ my_decimal *Item_in_subselect::val_decimal(my_decimal *decimal_value)
 }
 
 
-/* Rewrite a single-column IN/ALL/ANY subselect. */
+/* 
+  Rewrite a single-column IN/ALL/ANY subselect
+
+  SYNOPSIS
+    Item_in_subselect::single_value_transformer()
+      join  Join object of the subquery (i.e. 'child' join).
+      func  Subquery comparison creator
+
+  DESCRIPTION
+    Rewrite a single-column subquery using rule-based approach. The subquery
+    
+       oe $cmp$ (SELECT ie FROM ... WHERE subq_where ... HAVING subq_having)
+    
+    First, try to convert the subquery to scalar-result subquery in one of
+    the forms:
+    
+       - oe $cmp$ (SELECT MAX(...) )  // handled by Item_singlerow_subselect
+       - oe $cmp$ <max>(SELECT ...)   // handled by Item_maxmin_subselect
+   
+    If that fails, the subquery will be handled with class Item_in_optimizer, 
+    Inject the predicates into subquery, i.e. convert it to:
+
+    - If the subquery has aggregates, GROUP BY, or HAVING, convert to
+
+       SELECT ie FROM ...  HAVING subq_having AND 
+                                   trigcond(oe $cmp$ ref_or_null_helper<ie>)
+                                   
+      the addition is wrapped into trigger only when we want to distinguish
+      between NULL and FALSE results.
+
+    - Otherwise (no aggregates/GROUP BY/HAVING) convert it to one of the
+      following:
+
+      = If we don't need to distinguish between NULL and FALSE subquery:
+        
+        SELECT 1 FROM ... WHERE (oe $cmp$ ie) AND subq_where
+
+      = If we need to distinguish between those:
+
+        SELECT 1 FROM ...
+          WHERE  subq_where AND trigcond((oe $cmp$ ie) OR (ie IS NULL))
+          HAVING trigcond(<is_not_null_test>(ie))
+
+  RETURN
+    RES_OK     - OK, either subquery was transformed, or appopriate
+                 predicates where injected into it.
+    RES_REDUCE - The subquery was reduced to non-subquery
+    RES_ERROR  - Error
+*/
 
 Item_subselect::trans_res
 Item_in_subselect::single_value_transformer(JOIN *join,
@@ -903,8 +954,12 @@ Item_in_subselect::single_value_transformer(JOIN *join,
   select_lex->uncacheable|= UNCACHEABLE_DEPENDENT;
   /*
     Add the left part of a subselect to a WHERE or HAVING clause of
-    the right part, e.g. SELECT 1 IN (SELECT a FROM t1)  =>
-    SELECT Item_in_optimizer(1, SELECT a FROM t1 WHERE a=1)
+    the right part, e.g. 
+    
+       SELECT 1 IN (SELECT a FROM t1)  =>
+       
+       SELECT Item_in_optimizer(1, SELECT a FROM t1 WHERE a=1)
+       
     HAVING is used only if the right part contains a SUM function, a GROUP
     BY or a HAVING clause.
   */
@@ -919,10 +974,15 @@ Item_in_subselect::single_value_transformer(JOIN *join,
                                                       ref_pointer_array,
                                                       (char *)"<ref>",
                                                       this->full_name()));
-#ifdef CORRECT_BUT_TOO_SLOW_TO_BE_USABLE
-    if (!abort_on_null && left_expr->maybe_null)
-      item= new Item_cond_or(new Item_func_isnull(left_expr), item); 
-#endif
+    if (!abort_on_null && ((Item*)select_lex->item_list.head())->maybe_null)
+    {
+      /* 
+        We can encounter "NULL IN (SELECT ...)". Wrap the added condition
+        within a trigger.
+      */
+      item= new Item_func_trig_cond(item, &enable_pushed_conds);
+    }
+    
     /*
       AND and comparison functions can't be changed during fix_fields()
       we can assign select_lex->having here, and pass 0 as last
@@ -951,19 +1011,19 @@ Item_in_subselect::single_value_transformer(JOIN *join,
       select_lex->item_list.push_back(new Item_int("Not_used",
                                                    (longlong) 1, 21));
       select_lex->ref_pointer_array[0]= select_lex->item_list.head();
+       
       item= func->create(expr, item);
       if (!abort_on_null && orig_item->maybe_null)
       {
-	having= new Item_is_not_null_test(this, having);
+	having= 
+          new Item_func_trig_cond(new Item_is_not_null_test(this, having),
+                                  &enable_pushed_conds);
 	/*
 	  Item_is_not_null_test can't be changed during fix_fields()
 	  we can assign select_lex->having here, and pass 0 as last
 	  argument (reference) to fix_fields()
 	*/
-	select_lex->having=
-	  join->having= (join->having ?
-			 new Item_cond_and(having, join->having) :
-			 having);
+	select_lex->having= join->having= having;
 	select_lex->having_fix_field= 1;
         /*
           we do not check join->having->fixed, because Item_and (from
@@ -974,12 +1034,15 @@ Item_in_subselect::single_value_transformer(JOIN *join,
         select_lex->having_fix_field= 0;
         if (tmp)
 	  DBUG_RETURN(RES_ERROR);
+        /* 
+          NOTE: It is important that we add this "IS NULL" here, even when
+          orig_item can't be NULL. This is needed so that this predicate is
+          only used by ref[_or_null] analyzer (and, e.g. is not used by const
+          propagation).
+        */
 	item= new Item_cond_or(item,
 			       new Item_func_isnull(orig_item));
-#ifdef CORRECT_BUT_TOO_SLOW_TO_BE_USABLE
-        if (left_expr->maybe_null)
-          item= new Item_cond_or(new Item_func_isnull(left_expr), item);
-#endif
+        item= new Item_func_trig_cond(item, &enable_pushed_conds);
       }
       item->name= (char *)in_additional_cond;
       /*
@@ -1006,13 +1069,14 @@ Item_in_subselect::single_value_transformer(JOIN *join,
 	  we can assign select_lex->having here, and pass 0 as last
 	  argument (reference) to fix_fields()
 	*/
-	select_lex->having=
-	  join->having=
-	  func->create(expr,
+        Item *new_having=
+          func->create(expr,
                        new Item_ref_null_helper(&select_lex->context, this,
                                             select_lex->ref_pointer_array,
                                             (char *)"<no matter>",
                                             (char *)"<result>"));
+        new_having= new Item_func_trig_cond(new_having, &enable_pushed_conds);
+	select_lex->having= join->having= new_having;
 
 	select_lex->having_fix_field= 1;
         /*
@@ -1217,6 +1281,8 @@ Item_in_subselect::row_value_transformer(JOIN *join)
 
       where_item= and_items(where_item, item);
     }
+    if (where_item)
+      where_item= new Item_func_trig_cond(where_item, &enable_pushed_conds);
     /*
       AND can't be changed during fix_fields()
       we can assign select_lex->where here, and pass 0 as last
@@ -1230,6 +1296,8 @@ Item_in_subselect::row_value_transformer(JOIN *join)
   if (having_item)
   {
     bool res;
+    having_item= new Item_func_trig_cond(having_item, &enable_pushed_conds);
+
     select_lex->having= join->having= and_items(join->having, having_item);
     select_lex->having->top_level_item();
     /*
@@ -1446,6 +1514,27 @@ bool subselect_union_engine::is_executed() const
 }
 
 
+/*
+  Check if last execution of the subquery engine produced any rows
+
+  SYNOPSIS
+    subselect_union_engine::no_rows()
+
+  DESCRIPTION
+    Check if last execution of the subquery engine produced any rows. The
+    return value is undefined if last execution ended in an error.
+
+  RETURN
+    TRUE  - Last subselect execution has produced no rows
+    FALSE - Otherwise
+*/
+
+bool subselect_union_engine::no_rows()
+{
+  /* Check if we got any rows when reading UNION result from temp. table: */
+  return test(!unit->fake_select_lex->join->send_records);
+}
+
 void subselect_uniquesubquery_engine::cleanup()
 {
   DBUG_ENTER("subselect_uniquesubquery_engine::cleanup");
@@ -1511,6 +1600,28 @@ int subselect_uniquesubquery_engine::prepare()
   return 1;
 }
 
+
+/*
+  Check if last execution of the subquery engine produced any rows
+
+  SYNOPSIS
+    subselect_single_select_engine::no_rows()
+
+  DESCRIPTION
+    Check if last execution of the subquery engine produced any rows. The
+    return value is undefined if last execution ended in an error.
+
+  RETURN
+    TRUE  - Last subselect execution has produced no rows
+    FALSE - Otherwise
+*/
+
+bool subselect_single_select_engine::no_rows()
+{ 
+  return !item->assigned();
+}
+
+
 /* 
  makes storage for the output values for the subquery and calcuates 
  their data and column types and their nullability.
@@ -1569,7 +1680,11 @@ void subselect_uniquesubquery_engine::fix_length_and_dec(Item_cache **row)
   DBUG_ASSERT(0);
 }
 
-int subselect_single_select_engine::exec()
+int  init_read_record_seq(JOIN_TAB *tab);
+int join_read_always_key_or_null(JOIN_TAB *tab);
+int join_read_next_same_or_null(READ_RECORD *info);
+
+int subselect_single_select_engine::exec(bool full_scan)
 {
   DBUG_ENTER("subselect_single_select_engine::exec");
   char const *save_where= thd->where;
@@ -1607,7 +1722,43 @@ int subselect_single_select_engine::exec()
   if (!executed)
   {
     item->reset_value_registration();
+    if (full_scan)
+    {
+      /*
+        We should not apply optimizations based on the condition that was
+        pushed down into the subquery. Those optimizations are ref[_or_null]
+        acceses. Change them to be full table scans.
+      */
+      for (uint i=join->const_tables ; i < join->tables ; i++)
+      {
+        JOIN_TAB *tab=join->join_tab+i;
+        if (tab->keyuse && tab->keyuse->outer_ref)
+        {
+          tab->read_first_record= init_read_record_seq;
+          tab->read_record.record= tab->table->record[0];
+          tab->read_record.thd= join->thd;
+          tab->read_record.ref_length= tab->table->file->ref_length;
+        }
+      }
+    }
+    
     join->exec();
+
+    if (full_scan)
+    {
+      /* Enable the optimizations back */
+      for (uint i=join->const_tables ; i < join->tables ; i++)
+      {
+        JOIN_TAB *tab=join->join_tab+i;
+        if (tab->keyuse && tab->keyuse->outer_ref)
+        {
+          tab->read_record.record= 0;
+          tab->read_record.ref_length= 0;
+          tab->read_first_record= join_read_always_key_or_null;
+          tab->read_record.read_record= join_read_next_same_or_null;
+        }
+      }
+    }
     executed= 1;
     thd->where= save_where;
     thd->lex->current_select= save_select;
@@ -1618,29 +1769,159 @@ int subselect_single_select_engine::exec()
   DBUG_RETURN(0);
 }
 
-int subselect_union_engine::exec()
+int subselect_union_engine::exec(bool full_scan)
 {
   char const *save_where= thd->where;
+  /* 
+    Ignore the full_scan parameter: the pushed down predicates are only used
+    for filtering, and the caller has disabled them if necessary.
+  */
   int res= unit->exec();
   thd->where= save_where;
   return res;
 }
 
 
-int subselect_uniquesubquery_engine::exec()
+/*
+  Search for at least on row satisfying select condition
+ 
+  SYNOPSIS
+    subselect_uniquesubquery_engine::scan_table()
+
+  DESCRIPTION
+    Scan the table using sequential access until we find at least one row
+    satisfying select condition.
+    
+    The result of this function (info about whether a row was found) is
+    stored in this->empty_result_set.
+
+  RETURN
+    FALSE - OK
+    TRUE  - Error
+*/
+
+int subselect_uniquesubquery_engine::scan_table()
 {
-  DBUG_ENTER("subselect_uniquesubquery_engine::exec");
   int error;
   TABLE *table= tab->table;
-  for (store_key **copy=tab->ref.key_copy ; *copy ; copy++)
+  DBUG_ENTER("subselect_uniquesubquery_engine::scan_table");
+  empty_result_set= TRUE;
+
+  if (table->file->inited)
+    table->file->ha_index_end();
+ 
+  table->file->ha_rnd_init(1);
+  table->file->extra_opt(HA_EXTRA_CACHE,
+                         current_thd->variables.read_buff_size);
+  table->null_row= 0;
+  for (;;)
+  {
+    error=table->file->rnd_next(table->record[0]);
+    if (error && error != HA_ERR_END_OF_FILE)
+    {
+      error= report_error(table, error);
+      break;
+    }
+    /* No more rows */
+    if (table->status)
+      break;
+
+    if (!cond || cond->val_int())
+    {
+      empty_result_set= FALSE;
+      break;
+    }
+  }
+
+  table->file->ha_rnd_end();
+  DBUG_RETURN(error != 0);
+}
+
+
+/*
+  Copy ref key and check for null parts in it
+
+  SYNOPSIS
+    subselect_uniquesubquery_engine::copy_ref_key()
+
+  DESCRIPTION
+    Copy ref key and check for null parts in it.
+
+  RETURN
+    FALSE - ok, index lookup key without keys copied.
+    TRUE  - an error occured while copying the key
+*/
+
+bool subselect_uniquesubquery_engine::copy_ref_key()
+{
+  DBUG_ENTER("subselect_uniquesubquery_engine::copy_ref_key");
+
+  for (store_key **copy= tab->ref.key_copy ; *copy ; copy++)
   {
-    if ((tab->ref.key_err= (*copy)->copy()) & 1)
+    tab->ref.key_err= (*copy)->copy();
+
+    /*
+      When there is a NULL part in the key we don't need to make index
+      lookup for such key thus we don't need to copy whole key.
+      If we later should do a sequential scan return OK. Fail otherwise.
+
+      See also the comment for the subselect_uniquesubquery_engine::exec()
+      function.
+    */
+    null_keypart= (*copy)->null_key;
+    bool top_level= ((Item_in_subselect *) item)->is_top_level_item();
+    if (null_keypart && !top_level)
+      break;
+    if ((tab->ref.key_err) & 1 || (null_keypart && top_level))
     {
-      table->status= STATUS_NOT_FOUND;
+      tab->table->status= STATUS_NOT_FOUND;
       DBUG_RETURN(1);
     }
   }
+  DBUG_RETURN(0);
+}
+
+
+/*
+  Execute subselect
+
+  SYNOPSIS
+    subselect_uniquesubquery_engine::exec()
 
+  DESCRIPTION
+    Find rows corresponding to the ref key using index access.
+    If some part of the lookup key is NULL, then we're evaluating
+      NULL IN (SELECT ... )
+    This is a special case, we don't need to search for NULL in the table,
+    instead, the result value is 
+      - NULL  if select produces empty row set
+      - FALSE otherwise.
+
+    In some cases (IN subselect is a top level item, i.e. abort_on_null==TRUE)
+    the caller doesn't distinguish between NULL and FALSE result and we just 
+    return FALSE. 
+    Otherwise we make a full table scan to see if there is at least one matching row.
+  
+  NOTE
+    
+  RETURN
+    FALSE - ok
+    TRUE  - an error occured while scanning
+*/
+
+int subselect_uniquesubquery_engine::exec(bool full_scan)
+{
+  DBUG_ENTER("subselect_uniquesubquery_engine::exec");
+  int error;
+  TABLE *table= tab->table;
+ 
+  /* TODO: change to use of 'full_scan' here? */
+  if (copy_ref_key())
+    DBUG_RETURN(1);
+
+  if (null_keypart)
+    DBUG_RETURN(scan_table());
+ 
   if (!table->file->inited)
     table->file->ha_index_init(tab->ref.key);
   error= table->file->index_read(table->record[0],
@@ -1669,14 +1950,68 @@ subselect_uniquesubquery_engine::~subselect_uniquesubquery_engine()
 }
 
 
-int subselect_indexsubquery_engine::exec()
+/*
+  Index-lookup subselect 'engine' - run the subquery
+
+  SYNOPSIS
+    subselect_uniquesubquery_engine:exec()
+      full_scan 
+
+  DESCRIPTION
+    The engine is used to resolve subqueries in form
+
+      oe IN (SELECT key FROM tbl WHERE subq_where) 
+
+    The value of the predicate is calculated as follows: 
+    1. If oe IS NULL, this is a special case, do a full table scan on
+       table tbl and search for row that satisfies subq_where. If such 
+       row is found, return NULL, otherwise return FALSE.
+    2. Make an index lookup via key=oe, search for a row that satisfies
+       subq_where. If found, return TRUE.
+    3. If check_null==TRUE, make another lookup via key=NULL, search for a 
+       row that satisfies subq_where. If found, return NULL, otherwise
+       return FALSE.
+
+  TODO
+    The step #1 can be optimized further when the index has several key
+    parts. Consider a subquery:
+    
+      (oe1, oe2) IN (SELECT keypart1, keypart2 FROM tbl WHERE subq_where)
+
+    and suppose we need to evaluate it for {oe1, oe2}=={const1, NULL}.
+    Current code will do a full table scan and obtain correct result. There
+    is a better option: instead of evaluating
+
+      SELECT keypart1, keypart2 FROM tbl WHERE subq_where            (1)
+
+    and checking if it has produced any matching rows, evaluate
+    
+      SELECT keypart2 FROM tbl WHERE subq_where AND keypart1=const1  (2)
+
+    If this query produces a row, the result is NULL (as we're evaluating 
+    "(const1, NULL) IN { (const1, X), ... }", which has a value of UNKNOWN,
+    i.e. NULL).  If the query produces no rows, the result is FALSE.
+
+    We currently evaluate (1) by doing a full table scan. (2) can be
+    evaluated by doing a "ref" scan on "keypart1=const1", which can be much
+    cheaper. We can use index statistics to quickly check whether "ref" scan
+    will be cheaper than full table scan.
+
+  RETURN
+    0
+    1
+*/
+
+int subselect_indexsubquery_engine::exec(bool full_scan)
 {
-  DBUG_ENTER("subselect_indexsubselect_engine::exec");
+  DBUG_ENTER("subselect_indexsubquery_engine::exec");
   int error;
   bool null_finding= 0;
   TABLE *table= tab->table;
 
   ((Item_in_subselect *) item)->value= 0;
+  empty_result_set= TRUE;
+  null_keypart= 0;
 
   if (check_null)
   {
@@ -1685,14 +2020,12 @@ int subselect_indexsubquery_engine::exec()
     ((Item_in_subselect *) item)->was_null= 0;
   }
 
-  for (store_key **copy=tab->ref.key_copy ; *copy ; copy++)
-  {
-    if ((tab->ref.key_err= (*copy)->copy()) & 1)
-    {
-      table->status= STATUS_NOT_FOUND;
-      DBUG_RETURN(1);
-    }
-  }
+  /* Copy the ref key and check for nulls... */
+  if (copy_ref_key())
+    DBUG_RETURN(1);
+
+  if (null_keypart)
+    DBUG_RETURN(scan_table());
 
   if (!table->file->inited)
     table->file->ha_index_init(tab->ref.key);
diff --git a/sql/item_subselect.h b/sql/item_subselect.h
index a48ff3e2429..f1be99353cc 100644
--- a/sql/item_subselect.h
+++ b/sql/item_subselect.h
@@ -60,6 +60,9 @@ public:
   /* subquery is transformed */
   bool changed;
 
+  /* TRUE <=> The underlying SELECT is correlated w.r.t some ancestor select */
+  bool is_correlated; 
+
   enum trans_res {RES_OK, RES_REDUCE, RES_ERROR};
   enum subs_type {UNKNOWN_SUBS, SINGLEROW_SUBS,
 		  EXISTS_SUBS, IN_SUBS, ALL_SUBS, ANY_SUBS};
@@ -92,7 +95,7 @@ public:
     return null_value;
   }
   bool fix_fields(THD *thd, Item **ref);
-  virtual bool exec();
+  virtual bool exec(bool full_scan);
   virtual void fix_length_and_dec();
   table_map used_tables() const;
   table_map not_null_tables() const { return 0; }
@@ -114,6 +117,7 @@ public:
     single select and union subqueries only.
   */
   bool is_evaluated() const;
+  bool is_uncacheable() const;
 
   /*
     Used by max/min subquery to initialize value presence registration
@@ -216,7 +220,20 @@ public:
   friend class subselect_indexsubquery_engine;
 };
 
-/* IN subselect */
+
+/*
+  IN subselect: this represents "left_exr IN (SELECT ...)"
+
+  This class has: 
+   - (as a descendant of Item_subselect) a "subquery execution engine" which 
+      allows it to evaluate subqueries. (and this class participates in
+      execution by having was_null variable where part of execution result
+      is stored.
+   - Transformation methods (todo: more on this).
+
+  This class is not used directly, it is "wrapped" into Item_in_optimizer
+  which provides some small bits of subquery evaluation.
+*/
 
 class Item_in_subselect :public Item_exists_subselect
 {
@@ -232,12 +249,14 @@ protected:
   bool abort_on_null;
   bool transformed;
 public:
+  /* Used to trigger on/off conditions that were pushed down to subselect */
+  bool enable_pushed_conds;
   Item_func_not_all *upper_item; // point on NOT/NOP before ALL/SOME subquery
 
   Item_in_subselect(Item * left_expr, st_select_lex *select_lex);
   Item_in_subselect()
     :Item_exists_subselect(), optimizer(0), abort_on_null(0), transformed(0),
-     upper_item(0)
+     enable_pushed_conds(TRUE), upper_item(0)
   {}
 
   subs_type substype() { return IN_SUBS; }
@@ -257,6 +276,7 @@ public:
   my_decimal *val_decimal(my_decimal *);
   bool val_bool();
   void top_level_item() { abort_on_null=1; }
+  inline bool is_top_level_item() { return abort_on_null; }
   bool test_limit(st_select_lex_unit *unit);
   void print(String *str);
   bool fix_fields(THD *thd, Item **ref);
@@ -316,7 +336,28 @@ public:
   THD * get_thd() { return thd; }
   virtual int prepare()= 0;
   virtual void fix_length_and_dec(Item_cache** row)= 0;
-  virtual int exec()= 0;
+  /*
+    Execute the engine
+
+    SYNOPSIS
+      exec()
+        full_scan TRUE  - Pushed-down predicates are disabled, the engine
+                          must disable made based on those predicates.
+                  FALSE - Pushed-down predicates are in effect.
+    DESCRIPTION
+      Execute the engine. The result of execution is subquery value that is
+      either captured by previously set up select_result-based 'sink' or
+      stored somewhere by the exec() method itself.
+
+      A required side effect: if full_scan==TRUE, subselect_engine->no_rows()
+      should return correct result.
+
+    RETURN
+      0 - OK
+      1 - Either an execution error, or the engine was be "changed", and
+          caller should call exec() again for the new engine.
+  */
+  virtual int exec(bool full_scan)= 0;
   virtual uint cols()= 0; /* return number of columns in select */
   virtual uint8 uncacheable()= 0; /* query is uncacheable */
   enum Item_result type() { return res_type; }
@@ -329,6 +370,11 @@ public:
   virtual bool change_result(Item_subselect *si, select_subselect *result)= 0;
   virtual bool no_tables()= 0;
   virtual bool is_executed() const { return FALSE; }
+  /* Check if subquery produced any rows during last query execution */
+  virtual bool no_rows() = 0;
+
+protected:
+  void set_row(List<Item> &item_list, Item_cache **row);
 };
 
 
@@ -346,7 +392,7 @@ public:
   void cleanup();
   int prepare();
   void fix_length_and_dec(Item_cache** row);
-  int exec();
+  int exec(bool full_scan);
   uint cols();
   uint8 uncacheable();
   void exclude();
@@ -355,6 +401,7 @@ public:
   bool change_result(Item_subselect *si, select_subselect *result);
   bool no_tables();
   bool is_executed() const { return executed; }
+  bool no_rows();
 };
 
 
@@ -368,7 +415,7 @@ public:
   void cleanup();
   int prepare();
   void fix_length_and_dec(Item_cache** row);
-  int exec();
+  int exec(bool full_scan);
   uint cols();
   uint8 uncacheable();
   void exclude();
@@ -377,6 +424,7 @@ public:
   bool change_result(Item_subselect *si, select_subselect *result);
   bool no_tables();
   bool is_executed() const;
+  bool no_rows();
 };
 
 
@@ -386,6 +434,12 @@ class subselect_uniquesubquery_engine: public subselect_engine
 protected:
   st_join_table *tab;
   Item *cond;
+  /* 
+    TRUE<=> last execution produced empty set. Valid only when left
+    expression is NULL.
+  */
+  bool empty_result_set;
+  bool null_keypart; /* TRUE <=> constructed search tuple has a NULL */
 public:
 
   // constructor can assign THD because it will be called after JOIN::prepare
@@ -399,7 +453,7 @@ public:
   void cleanup();
   int prepare();
   void fix_length_and_dec(Item_cache** row);
-  int exec();
+  int exec(bool full_scan);
   uint cols() { return 1; }
   uint8 uncacheable() { return UNCACHEABLE_DEPENDENT; }
   void exclude();
@@ -407,11 +461,15 @@ public:
   void print (String *str);
   bool change_result(Item_subselect *si, select_subselect *result);
   bool no_tables();
+  int scan_table();
+  bool copy_ref_key();
+  bool no_rows() { return empty_result_set; }
 };
 
 
 class subselect_indexsubquery_engine: public subselect_uniquesubquery_engine
 {
+  /* FALSE for 'ref', TRUE for 'ref-or-null'. */
   bool check_null;
 public:
 
@@ -422,7 +480,7 @@ public:
     :subselect_uniquesubquery_engine(thd, tab_arg, subs, where),
      check_null(chk_null)
   {}
-  int exec();
+  int exec(bool full_scan);
   void print (String *str);
 };
 
@@ -432,3 +490,9 @@ inline bool Item_subselect::is_evaluated() const
   return engine->is_executed();
 }
 
+inline bool Item_subselect::is_uncacheable() const
+{
+  return engine->uncacheable();
+}
+
+
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index f1e0001c994..c2219aafd03 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -893,6 +893,7 @@ bool Item_sum_distinct::setup(THD *thd)
   tree= new Unique(simple_raw_key_cmp, &tree_key_length, tree_key_length,
                    thd->variables.max_heap_table_size);
 
+  is_evaluated= FALSE;
   DBUG_RETURN(tree == 0);
 }
 
@@ -900,6 +901,7 @@ bool Item_sum_distinct::setup(THD *thd)
 bool Item_sum_distinct::add()
 {
   args[0]->save_in_field(table->field[0], FALSE);
+  is_evaluated= FALSE;
   if (!table->field[0]->is_null())
   {
     DBUG_ASSERT(tree);
@@ -929,6 +931,7 @@ void Item_sum_distinct::clear()
   DBUG_ASSERT(tree != 0);                        /* we always have a tree */
   null_value= 1;
   tree->reset();
+  is_evaluated= FALSE;
   DBUG_VOID_RETURN;
 }
 
@@ -938,6 +941,7 @@ void Item_sum_distinct::cleanup()
   delete tree;
   tree= 0;
   table= 0;
+  is_evaluated= FALSE;
 }
 
 Item_sum_distinct::~Item_sum_distinct()
@@ -949,16 +953,20 @@ Item_sum_distinct::~Item_sum_distinct()
 
 void Item_sum_distinct::calculate_val_and_count()
 {
-  count= 0;
-  val.traits->set_zero(&val);
-  /*
-    We don't have a tree only if 'setup()' hasn't been called;
-    this is the case of sql_select.cc:return_zero_rows.
-  */
-  if (tree)
+  if (!is_evaluated)
   {
-    table->field[0]->set_notnull();
-    tree->walk(item_sum_distinct_walk, (void*) this);
+    count= 0;
+    val.traits->set_zero(&val);
+    /*
+      We don't have a tree only if 'setup()' hasn't been called;
+      this is the case of sql_select.cc:return_zero_rows.
+     */
+    if (tree)
+    {
+      table->field[0]->set_notnull();
+      tree->walk(item_sum_distinct_walk, (void*) this);
+    }
+    is_evaluated= TRUE;
   }
 }
 
@@ -1014,9 +1022,13 @@ Item_sum_avg_distinct::fix_length_and_dec()
 void
 Item_sum_avg_distinct::calculate_val_and_count()
 {
-  Item_sum_distinct::calculate_val_and_count();
-  if (count)
-    val.traits->div(&val, count);
+  if (!is_evaluated)
+  {
+    Item_sum_distinct::calculate_val_and_count();
+    if (count)
+      val.traits->div(&val, count);
+    is_evaluated= TRUE;
+  }
 }
 
 
@@ -2478,6 +2490,7 @@ void Item_sum_count_distinct::cleanup()
     */
     delete tree;
     tree= 0;
+    is_evaluated= FALSE;
     if (table)
     {
       free_tmp_table(table->in_use, table);
@@ -2499,6 +2512,7 @@ void Item_sum_count_distinct::make_unique()
   original= 0;
   force_copy_fields= 1;
   tree= 0;
+  is_evaluated= FALSE;
   tmp_table_param= 0;
   always_null= FALSE;
 }
@@ -2618,6 +2632,7 @@ bool Item_sum_count_distinct::setup(THD *thd)
       but this has to be handled - otherwise someone can crash
       the server with a DoS attack
     */
+    is_evaluated= FALSE;
     if (! tree)
       return TRUE;
   }
@@ -2634,8 +2649,11 @@ Item *Item_sum_count_distinct::copy_or_same(THD* thd)
 void Item_sum_count_distinct::clear()
 {
   /* tree and table can be both null only if always_null */
+  is_evaluated= FALSE;
   if (tree)
+  {
     tree->reset();
+  }
   else if (table)
   {
     table->file->extra(HA_EXTRA_NO_CACHE);
@@ -2656,6 +2674,7 @@ bool Item_sum_count_distinct::add()
     if ((*field)->is_real_null(0))
       return 0;					// Don't count NULL
 
+  is_evaluated= FALSE;
   if (tree)
   {
     /*
@@ -2682,12 +2701,14 @@ longlong Item_sum_count_distinct::val_int()
     return LL(0);
   if (tree)
   {
-    ulonglong count;
+    if (is_evaluated)
+      return count;
 
     if (tree->elements == 0)
       return (longlong) tree->elements_in_tree(); // everything fits in memory
     count= 0;
     tree->walk(count_distinct_walk, (void*) &count);
+    is_evaluated= TRUE;
     return (longlong) count;
   }
 
diff --git a/sql/item_sum.h b/sql/item_sum.h
index fe7edd76ecf..c11ef7e548a 100644
--- a/sql/item_sum.h
+++ b/sql/item_sum.h
@@ -352,12 +352,23 @@ public:
 
 class Item_sum_num :public Item_sum
 {
+protected:
+  /*
+   val_xxx() functions may be called several times during the execution of a 
+   query. Derived classes that require extensive calculation in val_xxx()
+   maintain cache of aggregate value. This variable governs the validity of 
+   that cache.
+  */
+  bool is_evaluated;
 public:
-  Item_sum_num() :Item_sum() {}
-  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(THD *thd, Item_sum_num *item) :Item_sum(thd, item) {}
+  Item_sum_num() :Item_sum(),is_evaluated(FALSE) {}
+  Item_sum_num(Item *item_par) 
+    :Item_sum(item_par), is_evaluated(FALSE) {}
+  Item_sum_num(Item *a, Item* b) :Item_sum(a,b),is_evaluated(FALSE) {}
+  Item_sum_num(List<Item> &list) 
+    :Item_sum(list), is_evaluated(FALSE) {}
+  Item_sum_num(THD *thd, Item_sum_num *item) 
+    :Item_sum(thd, item),is_evaluated(item->is_evaluated) {}
   bool fix_fields(THD *, Item **);
   longlong val_int()
   {
@@ -540,6 +551,12 @@ class Item_sum_count_distinct :public Item_sum_int
   */
   Unique *tree;
   /*
+   Storage for the value of count between calls to val_int() so val_int()
+   will not recalculate on each call. Validitiy of the value is stored in
+   is_evaluated.
+  */
+  longlong count;
+  /*
     Following is 0 normal object and pointer to original one for copy 
     (to correctly free resources)
   */
@@ -556,14 +573,15 @@ class Item_sum_count_distinct :public Item_sum_int
 public:
   Item_sum_count_distinct(List<Item> &list)
     :Item_sum_int(list), table(0), field_lengths(0), tmp_table_param(0),
-     force_copy_fields(0), tree(0), original(0), always_null(FALSE)
+     force_copy_fields(0), tree(0), count(0),
+     original(0), always_null(FALSE)
   { quick_group= 0; }
   Item_sum_count_distinct(THD *thd, Item_sum_count_distinct *item)
     :Item_sum_int(thd, item), table(item->table),
      field_lengths(item->field_lengths),
      tmp_table_param(item->tmp_table_param),
-     force_copy_fields(0), tree(item->tree), original(item),
-     tree_key_length(item->tree_key_length),
+     force_copy_fields(0), tree(item->tree), count(item->count), 
+     original(item), tree_key_length(item->tree_key_length),
      always_null(item->always_null)
   {}
   ~Item_sum_count_distinct();
diff --git a/sql/item_timefunc.cc b/sql/item_timefunc.cc
index a776d8a5ff7..232ad4b9213 100644
--- a/sql/item_timefunc.cc
+++ b/sql/item_timefunc.cc
@@ -1413,17 +1413,6 @@ String *Item_date::val_str(String *str)
 }
 
 
-int Item_date::save_in_field(Field *field, bool no_conversions)
-{
-  TIME ltime;
-  if (get_date(&ltime, TIME_FUZZY_DATE))
-    return set_field_to_null(field);
-  field->set_notnull();
-  field->store_time(&ltime, MYSQL_TIMESTAMP_DATE);
-  return 0;
-}
-
-
 longlong Item_date::val_int()
 {
   DBUG_ASSERT(fixed == 1);
diff --git a/sql/item_timefunc.h b/sql/item_timefunc.h
index e79c62e6ffb..68e8700d1b0 100644
--- a/sql/item_timefunc.h
+++ b/sql/item_timefunc.h
@@ -339,12 +339,20 @@ public:
     decimals=0;
     max_length=MAX_DATE_WIDTH*MY_CHARSET_BIN_MB_MAXLEN;
   }
-  int save_in_field(Field *to, bool no_conversions);
   Field *tmp_table_field(TABLE *t_arg)
   {
     return (new Field_date(maybe_null, name, t_arg, &my_charset_bin));
   }  
   bool result_as_longlong() { return TRUE; }
+  my_decimal *val_decimal(my_decimal *decimal_value)
+  {
+    DBUG_ASSERT(fixed == 1);
+    return  val_decimal_from_date(decimal_value);
+  }
+  int save_in_field(Field *field, bool no_conversions)
+  {
+    return save_date_in_field(field);
+  }
 };
 
 
@@ -361,21 +369,57 @@ public:
     return (new Field_datetime(maybe_null, name, t_arg, &my_charset_bin));
   }
   bool result_as_longlong() { return TRUE; }
+  my_decimal *val_decimal(my_decimal *decimal_value)
+  {
+    DBUG_ASSERT(fixed == 1);
+    return  val_decimal_from_date(decimal_value);
+  }
+  int save_in_field(Field *field, bool no_conversions)
+  {
+    return save_date_in_field(field);
+  }
+};
+
+
+class Item_str_timefunc :public Item_str_func
+{
+public:
+  Item_str_timefunc() :Item_str_func() {}
+  Item_str_timefunc(Item *a) :Item_str_func(a) {}
+  Item_str_timefunc(Item *a,Item *b) :Item_str_func(a,b) {}
+  Item_str_timefunc(Item *a, Item *b, Item *c) :Item_str_func(a, b ,c) {}
+  enum_field_types field_type() const { return MYSQL_TYPE_TIME; }
+  void fix_length_and_dec()
+  {
+    decimals=0;
+    max_length=MAX_TIME_WIDTH*MY_CHARSET_BIN_MB_MAXLEN;
+  }
+  Field *tmp_table_field(TABLE *t_arg)
+  {
+    return (new Field_time(maybe_null, name, t_arg, &my_charset_bin));
+  }
+  my_decimal *val_decimal(my_decimal *decimal_value)
+  {
+    DBUG_ASSERT(fixed == 1);
+    return  val_decimal_from_time(decimal_value);
+  }
+  int save_in_field(Field *field, bool no_conversions)
+  {
+    return save_time_in_field(field);
+  }
 };
 
 
 /* Abstract CURTIME function. Children should define what time zone is used */
 
-class Item_func_curtime :public Item_func
+class Item_func_curtime :public Item_str_timefunc
 {
   longlong value;
   char buff[9*2+32];
   uint buff_length;
 public:
-  Item_func_curtime() :Item_func() {}
-  Item_func_curtime(Item *a) :Item_func(a) {}
-  enum Item_result result_type () const { return STRING_RESULT; }
-  enum_field_types field_type() const { return MYSQL_TYPE_TIME; }
+  Item_func_curtime() :Item_str_timefunc() {}
+  Item_func_curtime(Item *a) :Item_str_timefunc(a) {}
   double val_real() { DBUG_ASSERT(fixed == 1); return (double) value; }
   longlong val_int() { DBUG_ASSERT(fixed == 1); return value; }
   String *val_str(String *str);
@@ -602,10 +646,10 @@ class Item_func_convert_tz :public Item_date_func
 };
 
 
-class Item_func_sec_to_time :public Item_str_func
+class Item_func_sec_to_time :public Item_str_timefunc
 {
 public:
-  Item_func_sec_to_time(Item *item) :Item_str_func(item) {}
+  Item_func_sec_to_time(Item *item) :Item_str_timefunc(item) {}
   double val_real()
   {
     DBUG_ASSERT(fixed == 1);
@@ -615,17 +659,12 @@ public:
   String *val_str(String *);
   void fix_length_and_dec()
   { 
+    Item_str_timefunc::fix_length_and_dec();
     collation.set(&my_charset_bin);
     maybe_null=1;
     decimals= DATETIME_DEC;
-    max_length=MAX_TIME_WIDTH*MY_CHARSET_BIN_MB_MAXLEN;
   }
-  enum_field_types field_type() const { return MYSQL_TYPE_TIME; }
   const char *func_name() const { return "sec_to_time"; }
-  Field *tmp_table_field(TABLE *t_arg)
-  {
-    return (new Field_time(maybe_null, name, t_arg, &my_charset_bin));
-  }
   bool result_as_longlong() { return TRUE; }
 };
 
@@ -762,6 +801,15 @@ public:
   }
   bool result_as_longlong() { return TRUE; }
   longlong val_int();
+  my_decimal *val_decimal(my_decimal *decimal_value)
+  {
+    DBUG_ASSERT(fixed == 1);
+    return  val_decimal_from_date(decimal_value);
+  }
+  int save_in_field(Field *field, bool no_conversions)
+  {
+    return save_date_in_field(field);
+  }
 };
 
 
@@ -780,6 +828,15 @@ public:
   }
   bool result_as_longlong() { return TRUE; }
   longlong val_int();
+  my_decimal *val_decimal(my_decimal *decimal_value)
+  {
+    DBUG_ASSERT(fixed == 1);
+    return  val_decimal_from_time(decimal_value);
+  }
+  int save_in_field(Field *field, bool no_conversions)
+  {
+    return save_time_in_field(field);
+  }
 };
 
 
@@ -797,12 +854,21 @@ public:
   }
   bool result_as_longlong() { return TRUE; }
   longlong val_int();
+  my_decimal *val_decimal(my_decimal *decimal_value)
+  {
+    DBUG_ASSERT(fixed == 1);
+    return  val_decimal_from_date(decimal_value);
+  }
+  int save_in_field(Field *field, bool no_conversions)
+  {
+    return save_date_in_field(field);
+  }
 };
 
-class Item_func_makedate :public Item_str_func
+class Item_func_makedate :public Item_date_func
 {
 public:
-  Item_func_makedate(Item *a,Item *b) :Item_str_func(a,b) {}
+  Item_func_makedate(Item *a,Item *b) :Item_date_func(a,b) {}
   String *val_str(String *str);
   const char *func_name() const { return "makedate"; }
   enum_field_types field_type() const { return MYSQL_TYPE_DATE; }
@@ -815,8 +881,16 @@ public:
   {
     return (new Field_date(maybe_null, name, t_arg, &my_charset_bin));
   }
-  bool result_as_longlong() { return TRUE; }
   longlong val_int();
+  my_decimal *val_decimal(my_decimal *decimal_value)
+  {
+    DBUG_ASSERT(fixed == 1);
+    return  val_decimal_from_date(decimal_value);
+  }
+  int save_in_field(Field *field, bool no_conversions)
+  {
+    return save_date_in_field(field);
+  }
 };
 
 
@@ -848,45 +922,46 @@ public:
   }
   void print(String *str);
   const char *func_name() const { return "add_time"; }
+  my_decimal *val_decimal(my_decimal *decimal_value)
+  {
+    DBUG_ASSERT(fixed == 1);
+    if (cached_field_type == MYSQL_TYPE_TIME)
+      return  val_decimal_from_time(decimal_value);
+    if (cached_field_type == MYSQL_TYPE_DATETIME)
+      return  val_decimal_from_date(decimal_value);
+    return Item_str_func::val_decimal(decimal_value);
+  }
+  int save_in_field(Field *field, bool no_conversions)
+  {
+    if (cached_field_type == MYSQL_TYPE_TIME)
+      return save_time_in_field(field);
+    if (cached_field_type == MYSQL_TYPE_DATETIME)
+      return save_date_in_field(field);
+    return Item_str_func::save_in_field(field, no_conversions);
+  }
 };
 
-class Item_func_timediff :public Item_str_func
+class Item_func_timediff :public Item_str_timefunc
 {
 public:
   Item_func_timediff(Item *a, Item *b)
-    :Item_str_func(a, b) {}
+    :Item_str_timefunc(a, b) {}
   String *val_str(String *str);
   const char *func_name() const { return "timediff"; }
-  enum_field_types field_type() const { return MYSQL_TYPE_TIME; }
   void fix_length_and_dec()
   {
-    decimals=0;
-    max_length=MAX_TIME_WIDTH*MY_CHARSET_BIN_MB_MAXLEN;
+    Item_str_timefunc::fix_length_and_dec();
     maybe_null= 1;
   }
-  Field *tmp_table_field(TABLE *t_arg)
-  {
-      return (new Field_time(maybe_null, name, t_arg, &my_charset_bin));
-  }
 };
 
-class Item_func_maketime :public Item_str_func
+class Item_func_maketime :public Item_str_timefunc
 {
 public:
   Item_func_maketime(Item *a, Item *b, Item *c)
-    :Item_str_func(a, b ,c) {}
+    :Item_str_timefunc(a, b ,c) {}
   String *val_str(String *str);
   const char *func_name() const { return "maketime"; }
-  enum_field_types field_type() const { return MYSQL_TYPE_TIME; }
-  void fix_length_and_dec()
-  {
-    decimals=0;
-    max_length=MAX_TIME_WIDTH*MY_CHARSET_BIN_MB_MAXLEN;
-  }
-  Field *tmp_table_field(TABLE *t_arg)
-  {
-    return (new Field_time(maybe_null, name, t_arg, &my_charset_bin));
-  }
 };
 
 class Item_func_microsecond :public Item_int_func
diff --git a/sql/my_decimal.cc b/sql/my_decimal.cc
index 1bd16940b47..f33609e0168 100644
--- a/sql/my_decimal.cc
+++ b/sql/my_decimal.cc
@@ -15,6 +15,8 @@
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
 
 #include "mysql_priv.h"
+#include <time.h>
+
 
 #ifndef MYSQL_CLIENT
 /*
@@ -190,6 +192,23 @@ int str2my_decimal(uint mask, const char *from, uint length,
 }
 
 
+my_decimal *date2my_decimal(TIME *ltime, my_decimal *dec)
+{
+  longlong date;
+  date = (ltime->year*100L + ltime->month)*100L + ltime->day;
+  if (ltime->time_type > MYSQL_TIMESTAMP_DATE)
+    date= ((date*100L + ltime->hour)*100L+ ltime->minute)*100L + ltime->second;
+  if (int2my_decimal(E_DEC_FATAL_ERROR, date, FALSE, dec))
+    return dec;
+  if (ltime->second_part)
+  {
+    dec->buf[(dec->intg-1) / 9 + 1]= ltime->second_part * 1000;
+    dec->frac= 6;
+  }
+  return dec;
+}
+
+
 #ifndef DBUG_OFF
 /* routines for debugging print */
 
diff --git a/sql/my_decimal.h b/sql/my_decimal.h
index b02abacf0a3..af3edade8d6 100644
--- a/sql/my_decimal.h
+++ b/sql/my_decimal.h
@@ -295,7 +295,12 @@ int string2my_decimal(uint mask, const String *str, my_decimal *d)
 {
   return str2my_decimal(mask, str->ptr(), str->length(), str->charset(), d);
 }
-#endif
+
+
+my_decimal *date2my_decimal(TIME *ltime, my_decimal *dec);
+
+
+#endif /*defined(MYSQL_SERVER) || defined(EMBEDDED_LIBRARY) */
 
 inline
 int double2my_decimal(uint mask, double val, my_decimal *d)
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index ac0b9f56567..a63b714e0b0 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -1482,7 +1482,7 @@ void end_read_record(READ_RECORD *info);
 ha_rows filesort(THD *thd, TABLE *form,struct st_sort_field *sortorder,
 		 uint s_length, SQL_SELECT *select,
 		 ha_rows max_rows, ha_rows *examined_rows);
-void filesort_free_buffers(TABLE *table);
+void filesort_free_buffers(TABLE *table, bool full);
 void change_double_for_sort(double nr,byte *to);
 double my_double_round(double value, int dec, bool truncate);
 int get_quick_record(SQL_SELECT *select);
diff --git a/sql/records.cc b/sql/records.cc
index b352f9f395a..78473659b22 100644
--- a/sql/records.cc
+++ b/sql/records.cc
@@ -20,7 +20,7 @@
 #include "mysql_priv.h"
 
 static int rr_quick(READ_RECORD *info);
-static int rr_sequential(READ_RECORD *info);
+int rr_sequential(READ_RECORD *info);
 static int rr_from_tempfile(READ_RECORD *info);
 static int rr_unpack_from_tempfile(READ_RECORD *info);
 static int rr_unpack_from_buffer(READ_RECORD *info);
@@ -184,6 +184,7 @@ void init_read_record(READ_RECORD *info,THD *thd, TABLE *table,
 } /* init_read_record */
 
 
+
 void end_read_record(READ_RECORD *info)
 {                   /* free cache if used */
   if (info->cache)
@@ -193,7 +194,7 @@ void end_read_record(READ_RECORD *info)
   }
   if (info->table)
   {
-    filesort_free_buffers(info->table);
+    filesort_free_buffers(info->table,0);
     (void) info->file->extra(HA_EXTRA_NO_CACHE);
     if (info->read_record != rr_quick) // otherwise quick_range does it
       (void) info->file->ha_index_or_rnd_end();
@@ -289,7 +290,7 @@ static int rr_index(READ_RECORD *info)
 }
 
 
-static int rr_sequential(READ_RECORD *info)
+int rr_sequential(READ_RECORD *info)
 {
   int tmp;
   while ((tmp=info->file->rnd_next(info->record)))
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 0f6715fc078..7c652fdcd4f 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -1483,6 +1483,7 @@ TABLE *open_table(THD *thd, TABLE_LIST *table_list, MEM_ROOT *mem_root,
   table->file->ft_handler= 0;
   if (table->timestamp_field)
     table->timestamp_field_type= table->timestamp_field->get_auto_set_type();
+  table->pos_in_table_list= table_list;
   table_list->updatable= 1; // It is not derived table nor non-updatable VIEW
   DBUG_ASSERT(table->key_read == 0);
   DBUG_RETURN(table);
@@ -2767,6 +2768,7 @@ TABLE *open_temporary_table(THD *thd, const char *path, const char *db,
     if (thd->slave_thread)
       slave_open_temp_tables++;
   }
+  tmp_table->pos_in_table_list= 0;
   DBUG_RETURN(tmp_table);
 }
 
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index f39cf39f08e..3de842c8551 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -162,6 +162,7 @@ void lex_start(THD *thd, uchar *buf,uint length)
   lex->select_lex.ftfunc_list= &lex->select_lex.ftfunc_list_alloc;
   lex->select_lex.group_list.empty();
   lex->select_lex.order_list.empty();
+  lex->select_lex.udf_list.empty();
   lex->current_select= &lex->select_lex;
   lex->yacc_yyss=lex->yacc_yyvs=0;
   lex->ignore_space=test(thd->variables.sql_mode & MODE_IGNORE_SPACE);
@@ -1165,6 +1166,7 @@ void st_select_lex::init_select()
   braces= 0;
   when_list.empty();
   expr_list.empty();
+  udf_list.empty();
   interval_list.empty();
   use_index.empty();
   ftfunc_list_alloc.empty();
@@ -1178,7 +1180,7 @@ void st_select_lex::init_select()
   select_limit= 0;      /* denotes the default limit = HA_POS_ERROR */
   offset_limit= 0;      /* denotes the default offset = 0 */
   with_sum_func= 0;
-
+  is_correlated= 0;
 }
 
 /*
@@ -1372,6 +1374,8 @@ void st_select_lex::mark_as_dependent(SELECT_LEX *last)
       SELECT_LEX_UNIT *munit= s->master_unit();
       munit->uncacheable|= UNCACHEABLE_DEPENDENT;
     }
+  is_correlated= TRUE;
+  this->master_unit()->item->is_correlated= TRUE;
 }
 
 bool st_select_lex_node::set_braces(bool value)      { return 1; }
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 398e5666c7f..5f968252cc3 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -470,7 +470,7 @@ public:
   void set_thd(THD *thd_arg) { thd= thd_arg; }
 
   friend void lex_start(THD *thd, uchar *buf, uint length);
-  friend int subselect_union_engine::exec();
+  friend int subselect_union_engine::exec(bool);
 
   List<Item> *get_unit_column_types();
 };
@@ -562,6 +562,8 @@ public:
     query processing end even if we use temporary table
   */
   bool subquery_in_having;
+  /* TRUE <=> this SELECT is correlated w.r.t. some ancestor select */
+  bool is_correlated;
   /*
     This variable is required to ensure proper work of subqueries and
     stored procedures. Generally, one should use the states of
@@ -581,6 +583,8 @@ public:
   /* exclude this select from check of unique_table() */
   bool exclude_from_table_unique_test;
 
+  List<udf_func>     udf_list;                  /* udf function calls stack */
+
   void init_query();
   void init_select();
   st_select_lex_unit* master_unit();
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index e3ee9f340cf..9ed29149831 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -3451,8 +3451,12 @@ end_with_restore_list:
         if (first_table->lock_type ==  TL_WRITE_CONCURRENT_INSERT &&
             thd->lock)
         {
+          /* INSERT ... SELECT should invalidate only the very first table */
+          TABLE_LIST *save_table= first_table->next_local;
+          first_table->next_local= 0;
           mysql_unlock_tables(thd, thd->lock);
           query_cache_invalidate3(thd, first_table, 1);
+          first_table->next_local= save_table;
           thd->lock=0;
         }
         delete result;
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index abadd0697ac..adb57e3e9f4 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -158,8 +158,8 @@ static int join_read_prev_same(READ_RECORD *info);
 static int join_read_prev(READ_RECORD *info);
 static int join_ft_read_first(JOIN_TAB *tab);
 static int join_ft_read_next(READ_RECORD *info);
-static int join_read_always_key_or_null(JOIN_TAB *tab);
-static int join_read_next_same_or_null(READ_RECORD *info);
+int join_read_always_key_or_null(JOIN_TAB *tab);
+int join_read_next_same_or_null(READ_RECORD *info);
 static COND *make_cond_for_table(COND *cond,table_map table,
 				 table_map used_table);
 static Item* part_of_refkey(TABLE *form,Field *field);
@@ -512,11 +512,12 @@ err:
   DBUG_RETURN(-1);				/* purecov: inspected */
 }
 
+
 /*
   test if it is known for optimisation IN subquery
 
-  SYNOPSYS
-    JOIN::test_in_subselect
+  SYNOPSIS
+    JOIN::test_in_subselect()
     where - pointer for variable in which conditions should be
             stored if subquery is known
 
@@ -551,6 +552,35 @@ bool JOIN::test_in_subselect(Item **where)
 
 
 /*
+  Check if the passed HAVING clause is a clause added by subquery optimizer
+
+  SYNOPSIS
+    is_having_subq_predicates()
+      having  Having clause
+
+  RETURN
+    TRUE   The passed HAVING clause was added by the subquery optimizer
+    FALSE  Otherwise
+*/
+
+bool is_having_subq_predicates(Item *having)
+{
+  if (having->type() == Item::FUNC_ITEM)
+  {
+    if (((Item_func *) having)->functype() == Item_func::ISNOTNULLTEST_FUNC)
+      return TRUE;
+    if (((Item_func *) having)->functype() == Item_func::TRIG_COND_FUNC)
+    {
+      having= ((Item_func*)having)->arguments()[0];
+      if (((Item_func *) having)->functype() == Item_func::ISNOTNULLTEST_FUNC)
+        return TRUE;
+    }
+    return TRUE;
+  }
+  return FALSE;
+}
+
+/*
   global select optimisation.
   return 0 - success
          1 - error
@@ -1018,9 +1048,7 @@ JOIN::optimize()
       }
     } else if (join_tab[0].type == JT_REF_OR_NULL &&
 	       join_tab[0].ref.items[0]->name == in_left_expr_name &&
-	       having->type() == Item::FUNC_ITEM &&
-	       ((Item_func *) having)->functype() ==
-	       Item_func::ISNOTNULLTEST_FUNC)
+               is_having_subq_predicates(having))
     {
       join_tab[0].type= JT_INDEX_SUBQUERY;
       error= 0;
@@ -1273,14 +1301,14 @@ JOIN::reinit()
     exec_tmp_table1->file->extra(HA_EXTRA_RESET_STATE);
     exec_tmp_table1->file->delete_all_rows();
     free_io_cache(exec_tmp_table1);
-    filesort_free_buffers(exec_tmp_table1);
+    filesort_free_buffers(exec_tmp_table1,0);
   }
   if (exec_tmp_table2)
   {
     exec_tmp_table2->file->extra(HA_EXTRA_RESET_STATE);
     exec_tmp_table2->file->delete_all_rows();
     free_io_cache(exec_tmp_table2);
-    filesort_free_buffers(exec_tmp_table2);
+    filesort_free_buffers(exec_tmp_table2,0);
   }
   if (items0)
     set_items_ref_array(items0);
@@ -2519,6 +2547,9 @@ typedef struct key_field_t {		// Used when finding key fields
     when val IS NULL.
   */
   bool          null_rejecting; 
+
+  /* TRUE<=> This ref access is an outer subquery reference access */
+  bool          outer_ref;
 } KEY_FIELD;
 
 /* Values in optimize */
@@ -2817,6 +2848,7 @@ add_key_field(KEY_FIELD **key_fields,uint and_level, Item_func *cond,
                                    cond->functype() == Item_func::MULT_EQUAL_FUNC) &&
                                   ((*value)->type() == Item::FIELD_ITEM) &&
                                   ((Item_field*)*value)->field->maybe_null());
+  (*key_fields)->outer_ref=      FALSE;
   (*key_fields)++;
 }
 
@@ -2875,7 +2907,7 @@ add_key_equal_fields(KEY_FIELD **key_fields, uint and_level,
 }
 
 static void
-add_key_fields(KEY_FIELD **key_fields,uint *and_level,
+add_key_fields(JOIN *join, KEY_FIELD **key_fields, uint *and_level,
                COND *cond, table_map usable_tables,
                SARGABLE_PARAM **sargables)
 {
@@ -2888,28 +2920,56 @@ add_key_fields(KEY_FIELD **key_fields,uint *and_level,
     {
       Item *item;
       while ((item=li++))
-	add_key_fields(key_fields,and_level,item,usable_tables,sargables);
+        add_key_fields(join, key_fields, and_level, item, usable_tables,
+                       sargables);
       for (; org_key_fields != *key_fields ; org_key_fields++)
 	org_key_fields->level= *and_level;
     }
     else
     {
       (*and_level)++;
-      add_key_fields(key_fields,and_level,li++,usable_tables,sargables);
+      add_key_fields(join, key_fields, and_level, li++, usable_tables,
+                     sargables);
       Item *item;
       while ((item=li++))
       {
 	KEY_FIELD *start_key_fields= *key_fields;
 	(*and_level)++;
-	add_key_fields(key_fields,and_level,item,usable_tables,sargables);
+        add_key_fields(join, key_fields, and_level, item, usable_tables,
+                       sargables);
 	*key_fields=merge_key_fields(org_key_fields,start_key_fields,
 				     *key_fields,++(*and_level));
       }
     }
     return;
   }
-  /* If item is of type 'field op field/constant' add it to key_fields */
 
+  /* 
+    Subquery optimization: check if the encountered condition is one
+    added by condition push down into subquery.
+  */
+  {
+    if (cond->type() == Item::FUNC_ITEM &&
+        ((Item_func*)cond)->functype() == Item_func::TRIG_COND_FUNC)
+    {
+      cond= ((Item_func*)cond)->arguments()[0];
+      if (!join->group_list && !join->order &&
+          join->unit->item && 
+          join->unit->item->substype() == Item_subselect::IN_SUBS &&
+          !join->unit->first_select()->next_select())
+      {
+        KEY_FIELD *save= *key_fields;
+        add_key_fields(join, key_fields, and_level, cond, usable_tables,
+                       sargables);
+        // Indicate that this ref access candidate is for subquery lookup:
+        for (; save != *key_fields; save++)
+          save->outer_ref= TRUE;
+      }
+      return;
+    }
+  }
+
+  /* If item is of type 'field op field/constant' add it to key_fields */
   if (cond->type() != Item::FUNC_ITEM)
     return;
   Item_func *cond_func= (Item_func*) cond;
@@ -3083,6 +3143,7 @@ add_key_part(DYNAMIC_ARRAY *keyuse_array,KEY_FIELD *key_field)
 	  keyuse.used_tables=key_field->val->used_tables();
 	  keyuse.optimize= key_field->optimize & KEY_OPTIMIZE_REF_OR_NULL;
           keyuse.null_rejecting= key_field->null_rejecting;
+          keyuse.outer_ref= key_field->outer_ref;
 	  VOID(insert_dynamic(keyuse_array,(gptr) &keyuse));
 	}
       }
@@ -3205,7 +3266,7 @@ sort_keyuse(KEYUSE *a,KEYUSE *b)
     Here we can add 'ref' access candidates for t1 and t2, but not for t3.
 */
 
-static void add_key_fields_for_nj(TABLE_LIST *nested_join_table,
+static void add_key_fields_for_nj(JOIN *join, TABLE_LIST *nested_join_table,
                                   KEY_FIELD **end, uint *and_level,
                                   SARGABLE_PARAM **sargables)
 {
@@ -3217,12 +3278,13 @@ static void add_key_fields_for_nj(TABLE_LIST *nested_join_table,
   while ((table= li++))
   {
     if (table->nested_join)
-      add_key_fields_for_nj(table, end, and_level, sargables);
+      add_key_fields_for_nj(join, table, end, and_level, sargables);
     else
       if (!table->on_expr)
         tables |= table->table->map;
   }
-  add_key_fields(end, and_level, nested_join_table->on_expr, tables, sargables);
+  add_key_fields(join, end, and_level, nested_join_table->on_expr, tables,
+                 sargables);
 }
 
 
@@ -3297,7 +3359,8 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
     return TRUE;
   if (cond)
   {
-    add_key_fields(&end,&and_level,cond,normal_tables,sargables);
+    add_key_fields(join_tab->join, &end, &and_level, cond, normal_tables,
+                   sargables);
     for (; field != end ; field++)
     {
       add_key_part(keyuse,field);
@@ -3319,8 +3382,9 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
       into account as well.
     */ 
     if (*join_tab[i].on_expr_ref)
-      add_key_fields(&end,&and_level,*join_tab[i].on_expr_ref,
-                     join_tab[i].table->map,sargables);
+      add_key_fields(join_tab->join, &end, &and_level, 
+                     *join_tab[i].on_expr_ref,
+                     join_tab[i].table->map, sargables);
   }
 
   /* Process ON conditions for the nested joins */
@@ -3330,7 +3394,8 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
     while ((table= li++))
     {
       if (table->nested_join)
-	add_key_fields_for_nj(table, &end, &and_level, sargables);
+        add_key_fields_for_nj(join_tab->join, table, &end, &and_level, 
+                              sargables);
     }
   }
 
@@ -6094,7 +6159,7 @@ void JOIN::cleanup(bool full)
     if (tables > const_tables) // Test for not-const tables
     {
       free_io_cache(table[const_tables]);
-      filesort_free_buffers(table[const_tables]);
+      filesort_free_buffers(table[const_tables],full);
     }
 
     if (full)
@@ -10794,6 +10859,13 @@ join_init_quick_read_record(JOIN_TAB *tab)
 }
 
 
+int rr_sequential(READ_RECORD *info);
+int init_read_record_seq(JOIN_TAB *tab)
+{
+  tab->read_record.read_record= rr_sequential;
+  return tab->read_record.file->ha_rnd_init(1);
+}
+
 static int
 test_if_quick_select(JOIN_TAB *tab)
 {
@@ -10922,7 +10994,7 @@ join_ft_read_next(READ_RECORD *info)
   Reading of key with key reference and one part that may be NULL
 */
 
-static int
+int
 join_read_always_key_or_null(JOIN_TAB *tab)
 {
   int res;
@@ -10938,7 +11010,7 @@ join_read_always_key_or_null(JOIN_TAB *tab)
 }
 
 
-static int
+int
 join_read_next_same_or_null(READ_RECORD *info)
 {
   int error;
@@ -13534,9 +13606,16 @@ setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
     if (real_pos->type() == Item::FIELD_ITEM)
     {
       Item_field *item;
-      pos= real_pos;
-      if (!(item= new Item_field(thd, ((Item_field*) pos))))
+      if (!(item= new Item_field(thd, ((Item_field*) real_pos))))
 	goto err;
+      if (pos->type() == Item::REF_ITEM)
+      {
+        /* preserve the names of the ref when dereferncing */
+        Item_ref *ref= (Item_ref *) pos;
+        item->db_name= ref->db_name;
+        item->table_name= ref->table_name;
+        item->name= ref->name;
+      }
       pos= item;
       if (item->field->flags & BLOB_FLAG)
       {
diff --git a/sql/sql_select.h b/sql/sql_select.h
index 30b8f834ddf..629b44538d8 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -36,6 +36,8 @@ typedef struct keyuse_t {
     satisfied if val has NULL 'value'.
   */
   bool null_rejecting;
+  /* TRUE<=> This ref access is an outer subquery reference access */
+  bool outer_ref;
 } KEYUSE;
 
 class store_key;
@@ -455,10 +457,11 @@ class store_key :public Sql_alloc
   Field *to_field;				// Store data here
   char *null_ptr;
   char err;
- public:
+public:
+  bool null_key; /* TRUE <=> the value of the key has a null part */
   enum store_key_result { STORE_KEY_OK, STORE_KEY_FATAL, STORE_KEY_CONV };
   store_key(THD *thd, Field *field_arg, char *ptr, char *null, uint length)
-    :null_ptr(null),err(0)
+    :null_ptr(null), err(0), null_key(0)
   {
     if (field_arg->type() == FIELD_TYPE_BLOB)
     {
@@ -496,6 +499,7 @@ class store_key_field: public store_key
   enum store_key_result copy()
   {
     copy_field.do_copy(&copy_field);
+    null_key= to_field->is_null();
     return err != 0 ? STORE_KEY_FATAL : STORE_KEY_OK;
   }
   const char *name() const { return field_name; }
@@ -516,8 +520,8 @@ public:
   enum store_key_result copy()
   {
     int res= item->save_in_field(to_field, 1);
+    null_key= to_field->is_null() || item->null_value;
     return (err != 0 || res > 2 ? STORE_KEY_FATAL : (store_key_result) res); 
-	                 
   }
   const char *name() const { return "func"; }
 };
@@ -547,6 +551,7 @@ public:
           err= res;
       }
     }
+    null_key= to_field->is_null() || item->null_value;
     return (err > 2 ?  STORE_KEY_FATAL : (store_key_result) err);
   }
   const char *name() const { return "const"; }
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index f107a57fe2b..1d524418480 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -3979,7 +3979,7 @@ bool get_schema_tables_result(JOIN *join)
         table_list->table->file->extra(HA_EXTRA_RESET_STATE);
         table_list->table->file->delete_all_rows();
         free_io_cache(table_list->table);
-        filesort_free_buffers(table_list->table);
+        filesort_free_buffers(table_list->table,1);
         table_list->table->null_row= 0;
       }
       else
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index f1de8e9c80b..c14529f6eb1 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -2267,7 +2267,6 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
       goto send_result;
     }
 
-    table->table->pos_in_table_list= table;
     if ((table->table->db_stat & HA_READ_ONLY) && open_for_modify)
     {
       char buff[FN_REFLEN + MYSQL_ERRMSG_SIZE];
@@ -4056,8 +4055,6 @@ bool mysql_checksum_table(THD *thd, TABLE_LIST *tables, HA_CHECK_OPT *check_opt)
     }
     else
     {
-      t->pos_in_table_list= table;
-
       if (t->file->table_flags() & HA_HAS_CHECKSUM &&
 	  !(check_opt->flags & T_EXTEND))
 	protocol->store((ulonglong)t->file->checksum());
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 6f24a42c07c..676f3f0e6ab 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -761,7 +761,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 
 %type <item_list>
 	expr_list udf_expr_list udf_expr_list2 when_list
-	ident_list ident_list_arg
+	ident_list ident_list_arg opt_expr_list
 
 %type <var_type>
         option_type opt_var_type opt_var_ident_type
@@ -4701,7 +4701,7 @@ simple_expr:
 	  { $$= new Item_func_trim($5,$3); }
 	| TRUNCATE_SYM '(' expr ',' expr ')'
 	  { $$= new Item_func_round($3,$5,1); }
-	| ident '.' ident '(' udf_expr_list ')'
+	| ident '.' ident '(' opt_expr_list ')'
 	  {
 	    LEX *lex= Lex;
 	    sp_name *name= new sp_name($1, $3);
@@ -4718,27 +4718,27 @@ simple_expr:
           {
 #ifdef HAVE_DLOPEN
             udf_func *udf= 0;
+            LEX *lex= Lex;
             if (using_udf_functions &&
                 (udf= find_udf($1.str, $1.length)) &&
                 udf->type == UDFTYPE_AGGREGATE)
             {
-              LEX *lex= Lex;
               if (lex->current_select->inc_in_sum_expr())
               {
                 yyerror(ER(ER_SYNTAX_ERROR));
                 YYABORT;
               }
             }
-            $<udf>$= udf;
+            lex->current_select->udf_list.push_front(udf);
 #endif
           }
           udf_expr_list ')'
           {
 #ifdef HAVE_DLOPEN
-            udf_func *udf= $<udf>3;
-            SELECT_LEX *sel= Select;
+            udf_func *udf;
+            LEX *lex= Lex;
 
-            if (udf)
+            if (NULL != (udf= lex->current_select->udf_list.pop()))
             {
               if (udf->type == UDFTYPE_AGGREGATE)
                 Select->in_sum_expr--;
@@ -4965,12 +4965,29 @@ udf_expr_list3:
 udf_expr:
 	remember_name expr remember_end select_alias
 	{
+          udf_func *udf= Select->udf_list.head();
+          /*
+           Use Item::name as a storage for the attribute value of user
+           defined function argument. It is safe to use Item::name
+           because the syntax will not allow having an explicit name here.
+           See WL#1017 re. udf attributes.
+          */
 	  if ($4.str)
           {
+            if (!udf)
+            {
+              /*
+                Disallow using AS to specify explicit names for the arguments
+                of stored routine calls
+              */
+              yyerror(ER(ER_SYNTAX_ERROR));
+              YYABORT;
+            }
+
             $2->is_autogenerated_name= FALSE;
 	    $2->set_name($4.str, $4.length, system_charset_info);
           }
-	  else
+	  else if (udf)
 	    $2->set_name($1, (uint) ($3 - $1), YYTHD->charset());
 	  $$= $2;
 	}
@@ -5131,6 +5148,11 @@ cast_type:
         | DECIMAL_SYM float_options { $$=ITEM_CAST_DECIMAL; Lex->charset= NULL; }
 	;
 
+opt_expr_list:
+	/* empty */ { $$= NULL; }
+	| expr_list { $$= $1;}
+	;
+
 expr_list:
 	{ Select->expr_list.push_front(new List<Item>); }
 	expr_list2
diff --git a/sql/table.cc b/sql/table.cc
index d72379efb32..5d5d5095e7c 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -3032,6 +3032,23 @@ void st_table_list::reinit_before_use(THD *thd)
          embedding->nested_join->join_list.head() == embedded);
 }
 
+/*
+  Return subselect that contains the FROM list this table is taken from
+
+  SYNOPSIS
+    st_table_list::containing_subselect()
+ 
+  RETURN
+    Subselect item for the subquery that contains the FROM list
+    this table is taken from if there is any
+    0 - otherwise
+
+*/
+
+Item_subselect *st_table_list::containing_subselect()
+{    
+  return (select_lex ? select_lex->master_unit()->item : 0);
+}
 
 /*****************************************************************************
 ** Instansiate templates
diff --git a/sql/table.h b/sql/table.h
index 5136ac2c4db..f0190353328 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -18,6 +18,7 @@
 /* Structs that defines the TABLE */
 
 class Item;				/* Needed by ORDER */
+class Item_subselect;
 class GRANT_TABLE;
 class st_select_lex_unit;
 class st_select_lex;
@@ -68,6 +69,9 @@ enum frm_type_enum
 typedef struct st_filesort_info
 {
   IO_CACHE *io_cache;           /* If sorted through filebyte                */
+  uchar   **sort_keys;          /* Buffer for sorting keys                   */
+  byte     *buffpek;            /* Buffer for buffpek structures             */
+  uint      buffpek_len;        /* Max number of buffpeks in the buffer      */
   byte     *addon_buf;          /* Pointer to a buffer if sorted with fields */
   uint      addon_length;       /* Length of the buffer                      */
   struct st_sort_addon_field *addon_field;     /* Pointer to the fields info */
@@ -678,6 +682,7 @@ typedef struct st_table_list
     procedure.
   */
   void reinit_before_use(THD *thd);
+  Item_subselect *containing_subselect();
 
 private:
   bool prep_check_option(THD *thd, uint8 check_opt_type);