Clean-up: Item_sum_variance and Item_variance_field had hybrid type

infrastructure, though in fact they always return REAL result. Removing hybrid type artifacts.

Author: Alexander Barkov

sql/item_sum.cc

@@ -1829,7 +1829,7 @@ static double variance_fp_recurrence_result(double s, ulonglong count, bool is_s
 
 
 Item_sum_variance::Item_sum_variance(THD *thd, Item_sum_variance *item):
- Item_sum_num(thd, item), hybrid_type(item->hybrid_type),
+ Item_sum_num(thd, item),
  count(item->count), sample(item->sample),
  prec_increment(item->prec_increment)
 {
@@ -1850,7 +1850,6 @@ void Item_sum_variance::fix_length_and_dec()
  type of the result is an implementation-defined aproximate numeric
  type.
  */
- hybrid_type= REAL_RESULT;
 
  switch (args[0]->result_type()) {
  case REAL_RESULT:
@@ -2712,29 +2711,6 @@ double Item_std_field::val_real()
 }
 
 
-my_decimal *Item_std_field::val_decimal(my_decimal *dec_buf)
-{
- /*
- We can't call val_decimal_from_real() for DECIMAL_RESULT as
- Item_variance_field::val_real() would cause an infinite loop
- */
- my_decimal tmp_dec, *dec;
- double nr;
- if (hybrid_type == REAL_RESULT)
- return val_decimal_from_real(dec_buf);
-
- dec= Item_variance_field::val_decimal(dec_buf);
- if (!dec)
- return 0;
- my_decimal2double(E_DEC_FATAL_ERROR, dec, &nr);
- DBUG_ASSERT(nr >= 0.0);
- nr= sqrt(nr);
- double2my_decimal(E_DEC_FATAL_ERROR, nr, &tmp_dec);
- my_decimal_round(E_DEC_FATAL_ERROR, &tmp_dec, decimals, FALSE, dec_buf);
- return dec_buf;
-}
-
-
 Item_variance_field::Item_variance_field(THD *thd, Item_sum_variance *item):
  Item_result_field(thd)
 {
@@ -2745,25 +2721,12 @@ Item_variance_field::Item_variance_field(THD *thd, Item_sum_variance *item):
  field=item->result_field;
  maybe_null=1;
  sample= item->sample;
- prec_increment= item->prec_increment;
- if ((hybrid_type= item->hybrid_type) == DECIMAL_RESULT)
- {
- f_scale0= item->f_scale0;
- f_precision0= item->f_precision0;
- dec_bin_size0= item->dec_bin_size0;
- f_scale1= item->f_scale1;
- f_precision1= item->f_precision1;
- dec_bin_size1= item->dec_bin_size1;
- }
 }
 
 
 double Item_variance_field::val_real()
 {
  // fix_fields() never calls for this Item
- if (hybrid_type == DECIMAL_RESULT)
- return val_real_from_decimal();
-
  double recurrence_s;
  ulonglong count;
  float8get(recurrence_s, (field->ptr + sizeof(double)));

sql/item_sum.h

@@ -826,11 +826,11 @@ class Item_sum_avg;
 
 class Item_avg_field :public Item_result_field
 {
-public:
  Field *field;
  Item_result hybrid_type;
  uint f_precision, f_scale, dec_bin_size;
  uint prec_increment;
+public:
  Item_avg_field(THD *thd, Item_result res_type, Item_sum_avg *item);
  enum Type type() const { return FIELD_AVG_ITEM; }
  double val_real();
@@ -898,14 +898,9 @@ class Item_sum_variance;
 
 class Item_variance_field :public Item_result_field
 {
-public:
  Field *field;
- Item_result hybrid_type;
- uint f_precision0, f_scale0;
- uint f_precision1, f_scale1;
- uint dec_bin_size0, dec_bin_size1;
  uint sample;
- uint prec_increment;
+public:
  Item_variance_field(THD *thd, Item_sum_variance *item);
  enum Type type() const {return FIELD_VARIANCE_ITEM; }
  double val_real();
@@ -916,12 +911,8 @@ class Item_variance_field :public Item_result_field
  my_decimal *val_decimal(my_decimal *dec_buf)
  { return val_decimal_from_real(dec_buf); }
  bool is_null() { update_null_value(); return null_value; }
- enum_field_types field_type() const
- {
- return hybrid_type == DECIMAL_RESULT ?
- MYSQL_TYPE_NEWDECIMAL : MYSQL_TYPE_DOUBLE;
- }
- enum Item_result result_type () const { return hybrid_type; }
+ enum_field_types field_type() const { return MYSQL_TYPE_DOUBLE; }
+ enum Item_result result_type () const { return REAL_RESULT; }
  bool check_vcol_func_processor(uchar *int_arg) 
  {
  return trace_unsupported_by_check_vcol_func_processor("var_field");
@@ -954,18 +945,13 @@ class Item_sum_variance : public Item_sum_num
  void fix_length_and_dec();
 
 public:
- Item_result hybrid_type;
- int cur_dec;
  double recurrence_m, recurrence_s; /* Used in recurrence relation. */
  ulonglong count;
- uint f_precision0, f_scale0;
- uint f_precision1, f_scale1;
- uint dec_bin_size0, dec_bin_size1;
  uint sample;
  uint prec_increment;
 
  Item_sum_variance(THD *thd, Item *item_par, uint sample_arg):
- Item_sum_num(thd, item_par), hybrid_type(REAL_RESULT), count(0),
+ Item_sum_num(thd, item_par), count(0),
  sample(sample_arg)
  {}
  Item_sum_variance(THD *thd, Item_sum_variance *item);
@@ -983,6 +969,7 @@ class Item_sum_variance : public Item_sum_num
  Item *copy_or_same(THD* thd);
  Field *create_tmp_field(bool group, TABLE *table, uint convert_blob_length);
  enum Item_result result_type () const { return REAL_RESULT; }
+ enum_field_types field_type() const { return MYSQL_TYPE_DOUBLE;}
  void cleanup()
  {
  count= 0;
@@ -998,9 +985,6 @@ class Item_std_field :public Item_variance_field
  Item_std_field(THD *thd, Item_sum_std *item);
  enum Type type() const { return FIELD_STD_ITEM; }
  double val_real();
- my_decimal *val_decimal(my_decimal *);
- enum Item_result result_type () const { return REAL_RESULT; }
- enum_field_types field_type() const { return MYSQL_TYPE_DOUBLE;}
 };
 
 /*
@@ -1020,8 +1004,6 @@ class Item_sum_std :public Item_sum_variance
  Item *result_item(THD *thd, Field *field);
  const char *func_name() const { return "std("; }
  Item *copy_or_same(THD* thd);
- enum Item_result result_type () const { return REAL_RESULT; }
- enum_field_types field_type() const { return MYSQL_TYPE_DOUBLE;}
 };
 
 // This class is a string or number function depending on num_func