Auto-merged fix for the bug#34384.

7 files changed, 198 insertions, 40 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 8fef62aacc1..3bd4744764e 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -7104,7 +7104,22 @@ int stored_field_cmp_to_item(THD *thd, Field *field, Item *item)
 
 Item_cache* Item_cache::get_cache(const Item *item)
 {
-  switch (item->result_type()) {
+  return get_cache(item, item->result_type());
+}
+
+
+/**
+  Get a cache item of given type.
+
+  @param item         value to be cached
+  @param type         required type of cache
+
+  @return cache item
+*/
+
+Item_cache* Item_cache::get_cache(const Item *item, const Item_result type)
+{
+  switch (type) {
   case INT_RESULT:
     return new Item_cache_int();
   case REAL_RESULT:
@@ -7122,6 +7137,12 @@ Item_cache* Item_cache::get_cache(const Item *item)
   }
 }
 
+void Item_cache::store(Item *item)
+{
+  if (item)
+    example= item;
+  value_cached= FALSE;
+}
 
 void Item_cache::print(String *str, enum_query_type query_type)
 {
@@ -7133,17 +7154,19 @@ void Item_cache::print(String *str, enum_query_type query_type)
   str->append(')');
 }
 
-
-void Item_cache_int::store(Item *item)
+void  Item_cache_int::cache_value()
 {
-  value= item->val_int_result();
-  null_value= item->null_value;
-  unsigned_flag= item->unsigned_flag;
+  value_cached= TRUE;
+  value= example->val_int_result();
+  null_value= example->null_value;
+  unsigned_flag= example->unsigned_flag;
 }
 
 
 void Item_cache_int::store(Item *item, longlong val_arg)
 {
+  /* An explicit values is given, save it. */
+  value_cached= TRUE;
   value= val_arg;
   null_value= item->null_value;
   unsigned_flag= item->unsigned_flag;
@@ -7153,6 +7176,8 @@ void Item_cache_int::store(Item *item, longlong val_arg)
 String *Item_cache_int::val_str(String *str)
 {
   DBUG_ASSERT(fixed == 1);
+  if (!value_cached)
+    cache_value();
   str->set(value, default_charset());
   return str;
 }
@@ -7161,21 +7186,49 @@ String *Item_cache_int::val_str(String *str)
 my_decimal *Item_cache_int::val_decimal(my_decimal *decimal_val)
 {
   DBUG_ASSERT(fixed == 1);
+  if (!value_cached)
+    cache_value();
   int2my_decimal(E_DEC_FATAL_ERROR, value, unsigned_flag, decimal_val);
   return decimal_val;
 }
 
+double Item_cache_int::val_real()
+{
+  DBUG_ASSERT(fixed == 1);
+  if (!value_cached)
+    cache_value();
+  return (double) value;
+}
 
-void Item_cache_real::store(Item *item)
+longlong Item_cache_int::val_int()
 {
-  value= item->val_result();
-  null_value= item->null_value;
+  DBUG_ASSERT(fixed == 1);
+  if (!value_cached)
+    cache_value();
+  return value;
 }
 
+void Item_cache_real::cache_value()
+{
+  value_cached= TRUE;
+  value= example->val_result();
+  null_value= example->null_value;
+}
+
+
+double Item_cache_real::val_real()
+{
+  DBUG_ASSERT(fixed == 1);
+  if (!value_cached)
+    cache_value();
+  return value;
+}
 
 longlong Item_cache_real::val_int()
 {
   DBUG_ASSERT(fixed == 1);
+  if (!value_cached)
+    cache_value();
   return (longlong) rint(value);
 }
 
@@ -7183,6 +7236,8 @@ longlong Item_cache_real::val_int()
 String* Item_cache_real::val_str(String *str)
 {
   DBUG_ASSERT(fixed == 1);
+  if (!value_cached)
+    cache_value();
   str->set_real(value, decimals, default_charset());
   return str;
 }
@@ -7191,15 +7246,18 @@ String* Item_cache_real::val_str(String *str)
 my_decimal *Item_cache_real::val_decimal(my_decimal *decimal_val)
 {
   DBUG_ASSERT(fixed == 1);
+  if (!value_cached)
+    cache_value();
   double2my_decimal(E_DEC_FATAL_ERROR, value, decimal_val);
   return decimal_val;
 }
 
 
-void Item_cache_decimal::store(Item *item)
+void Item_cache_decimal::cache_value()
 {
-  my_decimal *val= item->val_decimal_result(&decimal_value);
-  if (!(null_value= item->null_value) && val != &decimal_value)
+  value_cached= TRUE;
+  my_decimal *val= example->val_decimal_result(&decimal_value);
+  if (!(null_value= example->null_value) && val != &decimal_value)
     my_decimal2decimal(val, &decimal_value);
 }
 
@@ -7207,6 +7265,8 @@ double Item_cache_decimal::val_real()
 {
   DBUG_ASSERT(fixed);
   double res;
+  if (!value_cached)
+    cache_value();
   my_decimal2double(E_DEC_FATAL_ERROR, &decimal_value, &res);
   return res;
 }
@@ -7215,6 +7275,8 @@ longlong Item_cache_decimal::val_int()
 {
   DBUG_ASSERT(fixed);
   longlong res;
+  if (!value_cached)
+    cache_value();
   my_decimal2int(E_DEC_FATAL_ERROR, &decimal_value, unsigned_flag, &res);
   return res;
 }
@@ -7222,6 +7284,8 @@ longlong Item_cache_decimal::val_int()
 String* Item_cache_decimal::val_str(String *str)
 {
   DBUG_ASSERT(fixed);
+  if (!value_cached)
+    cache_value();
   my_decimal_round(E_DEC_FATAL_ERROR, &decimal_value, decimals, FALSE,
                    &decimal_value);
   my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value, 0, 0, 0, str);
@@ -7231,15 +7295,18 @@ String* Item_cache_decimal::val_str(String *str)
 my_decimal *Item_cache_decimal::val_decimal(my_decimal *val)
 {
   DBUG_ASSERT(fixed);
+  if (!value_cached)
+    cache_value();
   return &decimal_value;
 }
 
 
-void Item_cache_str::store(Item *item)
+void Item_cache_str::cache_value()
 {
-  value_buff.set(buffer, sizeof(buffer), item->collation.collation);
-  value= item->str_result(&value_buff);
-  if ((null_value= item->null_value))
+  value_cached= TRUE;
+  value_buff.set(buffer, sizeof(buffer), example->collation.collation);
+  value= example->str_result(&value_buff);
+  if ((null_value= example->null_value))
     value= 0;
   else if (value != &value_buff)
   {
@@ -7261,6 +7328,8 @@ double Item_cache_str::val_real()
   DBUG_ASSERT(fixed == 1);
   int err_not_used;
   char *end_not_used;
+  if (!value_cached)
+    cache_value();
   if (value)
     return my_strntod(value->charset(), (char*) value->ptr(),
 		      value->length(), &end_not_used, &err_not_used);
@@ -7272,6 +7341,8 @@ longlong Item_cache_str::val_int()
 {
   DBUG_ASSERT(fixed == 1);
   int err;
+  if (!value_cached)
+    cache_value();
   if (value)
     return my_strntoll(value->charset(), value->ptr(),
 		       value->length(), 10, (char**) 0, &err);
@@ -7279,9 +7350,21 @@ longlong Item_cache_str::val_int()
     return (longlong)0;
 }
 
+
+String* Item_cache_str::val_str(String *str)
+{
+  DBUG_ASSERT(fixed == 1);
+  if (!value_cached)
+    cache_value();
+  return value;
+}
+
+
 my_decimal *Item_cache_str::val_decimal(my_decimal *decimal_val)
 {
   DBUG_ASSERT(fixed == 1);
+  if (!value_cached)
+    cache_value();
   if (value)
     string2my_decimal(E_DEC_FATAL_ERROR, value, decimal_val);
   else
@@ -7292,6 +7375,8 @@ my_decimal *Item_cache_str::val_decimal(my_decimal *decimal_val)
 
 int Item_cache_str::save_in_field(Field *field, bool no_conversions)
 {
+  if (!value_cached)
+    cache_value();
   int res= Item_cache::save_in_field(field, no_conversions);
   return (is_varbinary && field->type() == MYSQL_TYPE_STRING &&
           value->length() < field->field_length) ? 1 : res;
@@ -7326,11 +7411,19 @@ bool Item_cache_row::setup(Item * item)
 
 void Item_cache_row::store(Item * item)
 {
+  for (uint i= 0; i < item_count; i++)
+    values[i]->store(item->element_index(i));
+}
+
+
+void Item_cache_row::cache_value()
+{
+  value_cached= TRUE;
   null_value= 0;
-  item->bring_value();
+  example->bring_value();
   for (uint i= 0; i < item_count; i++)
   {
-    values[i]->store(item->element_index(i));
+    values[i]->cache_value();
     null_value|= values[i]->null_value;
   }
 }
diff --git a/sql/item.h b/sql/item.h
index 72e4e37342a..f69fa742744 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -1032,7 +1032,11 @@ class sp_head;
 
 class Item_basic_constant :public Item
 {
+  table_map used_table_map;
 public:
+  Item_basic_constant(): Item(), used_table_map(0) {};
+  void set_used_tables(table_map map) { used_table_map= map; }
+  table_map used_tables() const { return used_table_map; }
   /* to prevent drop fixed flag (no need parent cleanup call) */
   void cleanup()
   {
@@ -2918,15 +2922,25 @@ protected:
   */  
   Field *cached_field;
   enum enum_field_types cached_field_type;
+  /*
+    TRUE <=> cache holds value of the last stored item (i.e actual value).
+    store() stores item to be cached and sets this flag to FALSE.
+    On the first call of val_xxx function if this flag is set to FALSE the 
+    cache_value() will be called to actually cache value of saved item.
+    cache_value() will set this flag to TRUE.
+  */
+  bool value_cached;
 public:
-  Item_cache(): 
-    example(0), used_table_map(0), cached_field(0), cached_field_type(MYSQL_TYPE_STRING) 
+  Item_cache():
+    example(0), used_table_map(0), cached_field(0), cached_field_type(MYSQL_TYPE_STRING),
+    value_cached(0)
   {
     fixed= 1; 
     null_value= 1;
   }
   Item_cache(enum_field_types field_type_arg):
-    example(0), used_table_map(0), cached_field(0), cached_field_type(field_type_arg)
+    example(0), used_table_map(0), cached_field(0), cached_field_type(field_type_arg),
+    value_cached(0)
   {
     fixed= 1;
     null_value= 1;
@@ -2946,10 +2960,10 @@ public:
       cached_field= ((Item_field *)item)->field;
     return 0;
   };
-  virtual void store(Item *)= 0;
   enum Type type() const { return CACHE_ITEM; }
   enum_field_types field_type() const { return cached_field_type; }
   static Item_cache* get_cache(const Item *item);
+  static Item_cache* get_cache(const Item* item, const Item_result type);
   table_map used_tables() const { return used_table_map; }
   virtual void keep_array() {}
   virtual void print(String *str, enum_query_type query_type);
@@ -2961,6 +2975,8 @@ public:
   {
     return this == item;
   }
+  virtual void store(Item *item);
+  virtual void cache_value()= 0;
 };
 
 
@@ -2969,18 +2985,19 @@ class Item_cache_int: public Item_cache
 protected:
   longlong value;
 public:
-  Item_cache_int(): Item_cache(), value(0) {}
+  Item_cache_int(): Item_cache(),
+    value(0) {}
   Item_cache_int(enum_field_types field_type_arg):
     Item_cache(field_type_arg), value(0) {}
 
-  void store(Item *item);
   void store(Item *item, longlong val_arg);
-  double val_real() { DBUG_ASSERT(fixed == 1); return (double) value; }
-  longlong val_int() { DBUG_ASSERT(fixed == 1); return value; }
+  double val_real();
+  longlong val_int();
   String* val_str(String *str);
   my_decimal *val_decimal(my_decimal *);
   enum Item_result result_type() const { return INT_RESULT; }
   bool result_as_longlong() { return TRUE; }
+  void cache_value();
 };
 
 
@@ -2988,14 +3005,15 @@ class Item_cache_real: public Item_cache
 {
   double value;
 public:
-  Item_cache_real(): Item_cache(), value(0) {}
+  Item_cache_real(): Item_cache(),
+    value(0) {}
 
-  void store(Item *item);
-  double val_real() { DBUG_ASSERT(fixed == 1); return value; }
+  double val_real();
   longlong val_int();
   String* val_str(String *str);
   my_decimal *val_decimal(my_decimal *);
   enum Item_result result_type() const { return REAL_RESULT; }
+  void cache_value();
 };
 
 
@@ -3006,12 +3024,12 @@ protected:
 public:
   Item_cache_decimal(): Item_cache() {}
 
-  void store(Item *item);
   double val_real();
   longlong val_int();
   String* val_str(String *str);
   my_decimal *val_decimal(my_decimal *);
   enum Item_result result_type() const { return DECIMAL_RESULT; }
+  void cache_value();
 };
 
 
@@ -3029,14 +3047,14 @@ public:
                    MYSQL_TYPE_VARCHAR &&
                  !((const Item_field *) item)->field->has_charset())
   {}
-  void store(Item *item);
   double val_real();
   longlong val_int();
-  String* val_str(String *) { DBUG_ASSERT(fixed == 1); return value; }
+  String* val_str(String *);
   my_decimal *val_decimal(my_decimal *);
   enum Item_result result_type() const { return STRING_RESULT; }
   CHARSET_INFO *charset() const { return value->charset(); };
   int save_in_field(Field *field, bool no_conversions);
+  void cache_value();
 };
 
 class Item_cache_row: public Item_cache
@@ -3046,7 +3064,8 @@ class Item_cache_row: public Item_cache
   bool save_array;
 public:
   Item_cache_row()
-    :Item_cache(), values(0), item_count(2), save_array(0) {}
+    :Item_cache(), values(0), item_count(2),
+    save_array(0) {}
   
   /*
     'allocate' used only in row transformer, to preallocate space for row 
@@ -3104,6 +3123,7 @@ public:
       values= 0;
     DBUG_VOID_RETURN;
   }
+  void cache_value();
 };
 
 
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 9e0fe0b2562..fabb9a64b0d 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -882,13 +882,13 @@ int Arg_comparator::set_cmp_func(Item_bool_func2 *owner_arg,
 {
   enum enum_date_cmp_type cmp_type;
   ulonglong const_value= (ulonglong)-1;
+  thd= current_thd;
+  owner= owner_arg;
   a= a1;
   b= a2;
 
   if ((cmp_type= can_compare_as_dates(*a, *b, &const_value)))
   {
-    thd= current_thd;
-    owner= owner_arg;
     a_type= (*a)->field_type();
     b_type= (*b)->field_type();
     a_cache= 0;
@@ -896,6 +896,10 @@ int Arg_comparator::set_cmp_func(Item_bool_func2 *owner_arg,
 
     if (const_value != (ulonglong)-1)
     {
+      /*
+        cache_converted_constant can't be used here because it can't
+        correctly convert a DATETIME value from string to int representation.
+      */
       Item_cache_int *cache= new Item_cache_int();
       /* Mark the cache as non-const to prevent re-caching. */
       cache->set_used_tables(1);
@@ -921,8 +925,6 @@ int Arg_comparator::set_cmp_func(Item_bool_func2 *owner_arg,
            (*b)->field_type() == MYSQL_TYPE_TIME)
   {
     /* Compare TIME values as integers. */
-    thd= current_thd;
-    owner= owner_arg;
     a_cache= 0;
     b_cache= 0;
     is_nulls_eq= test(owner && owner->functype() == Item_func::EQUAL_FUNC);
@@ -941,10 +943,46 @@ int Arg_comparator::set_cmp_func(Item_bool_func2 *owner_arg,
       return 1;
   }
 
+  a= cache_converted_constant(thd, a, &a_cache, type);
+  b= cache_converted_constant(thd, b, &b_cache, type);
   return set_compare_func(owner_arg, type);
 }
 
 
+/**
+  Convert and cache a constant.
+
+  @param value      [in]  An item to cache
+  @param cache_item [out] Placeholder for the cache item
+  @param type       [in]  Comparison type
+
+  @details
+    When given item is a constant and its type differs from comparison type
+    then cache its value to avoid type conversion of this constant on each
+    evaluation. In this case the value is cached and the reference to the cache
+    is returned.
+    Original value is returned otherwise.
+
+  @return cache item or original value.
+*/
+
+Item** Arg_comparator::cache_converted_constant(THD *thd, Item **value,
+                                                Item **cache_item,
+                                                Item_result type)
+{
+  /* Don't need cache if doing context analysis only. */
+  if (!thd->is_context_analysis_only() &&
+      (*value)->const_item() && type != (*value)->result_type())
+  {
+    Item_cache *cache= Item_cache::get_cache(*value, type);
+    cache->store(*value);
+    *cache_item= cache;
+    return cache_item;
+  }
+  return value;
+}
+
+
 void Arg_comparator::set_datetime_cmp_func(Item **a1, Item **b1)
 {
   thd= current_thd;
@@ -1583,6 +1621,7 @@ longlong Item_in_optimizer::val_int()
   bool tmp;
   DBUG_ASSERT(fixed == 1);
   cache->store(args[0]);
+  cache->cache_value();
   
   if (cache->null_value)
   {
diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h
index 8354f6a5d30..c179840746e 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -97,6 +97,8 @@ public:
                                                       ulonglong *const_val_arg);
 
   void set_datetime_cmp_func(Item **a1, Item **b1);
+  Item** cache_converted_constant(THD *thd, Item **value, Item **cache,
+                                  Item_result type);
   static arg_cmp_func comparator_matrix [5][2];
 
   friend class Item_func;
diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index a619827b2d3..267a4b38450 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -480,6 +480,7 @@ Item_singlerow_subselect::select_transformer(JOIN *join)
 void Item_singlerow_subselect::store(uint i, Item *item)
 {
   row[i]->store(item);
+  row[i]->cache_value();
 }
 
 enum Item_result Item_singlerow_subselect::result_type() const
@@ -1826,6 +1827,7 @@ void subselect_engine::set_row(List<Item> &item_list, Item_cache **row)
     if (!(row[i]= Item_cache::get_cache(sel_item)))
       return;
     row[i]->setup(sel_item);
+    row[i]->store(sel_item);
   }
   if (item_list.elements > 1)
     res_type= ROW_RESULT;
diff --git a/sql/item_xmlfunc.cc b/sql/item_xmlfunc.cc
index 1eff00027f2..3e20b90e68e 100644
--- a/sql/item_xmlfunc.cc
+++ b/sql/item_xmlfunc.cc
@@ -941,14 +941,16 @@ static Item *create_comparator(MY_XPATH *xpath,
      in a loop through all of the nodes in the node set.
     */
 
-    Item *fake= new Item_string("", 0, xpath->cs);
+    Item_string *fake= new Item_string("", 0, xpath->cs);
+    /* Don't cache fake because its value will be changed during comparison.*/
+    fake->set_used_tables(RAND_TABLE_BIT);
     Item_nodeset_func *nodeset;
     Item *scalar, *comp;
     if (a->type() == Item::XPATH_NODESET)
     {
       nodeset= (Item_nodeset_func*) a;
       scalar= b;
-      comp= eq_func(oper, fake, scalar);
+      comp= eq_func(oper, (Item*)fake, scalar);
     }
     else
     {
diff --git a/sql/sp_rcontext.cc b/sql/sp_rcontext.cc
index 51b797fe088..d966de03b4e 100644
--- a/sql/sp_rcontext.cc
+++ b/sql/sp_rcontext.cc
@@ -669,7 +669,7 @@ sp_rcontext::set_case_expr(THD *thd, int case_expr_id, Item **case_expr_item_ptr
   }
 
   m_case_expr_holders[case_expr_id]->store(case_expr_item);
-
+  m_case_expr_holders[case_expr_id]->cache_value();
   return FALSE;
 }