Adding "virtual bool Field::can_optimize_range(...)" and moving the code

from Item_bool_func::get_mm_leaf() into Field_xxx::can_optimize_range().
This reduces the total amount of virtual calls. Also, it's a prerequisite
change for the pluggable data types.

sql/field.cc

@@ -1309,6 +1309,19 @@ bool Field::can_optimize_group_min_max(const Item_bool_func *cond,
 }
 
 
+/*
+  This covers all numeric types, ENUM, SET, BIT
+*/
+bool Field::can_optimize_range(const Item_bool_func *cond,
+                               const Item *item,
+                               bool is_eq_func) const
+{
+  DBUG_ASSERT(cmp_type() != TIME_RESULT);   // Handled in Field_temporal
+  DBUG_ASSERT(cmp_type() != STRING_RESULT); // Handled in Field_longstr
+  return item->cmp_type() != TIME_RESULT;
+}
+
+
 /**
   Numeric fields base class constructor.
 */
@@ -6955,6 +6968,16 @@ bool Field_longstr::can_optimize_group_min_max(const Item_bool_func *cond,
 }
 
 
+bool Field_longstr::can_optimize_range(const Item_bool_func *cond,
+                                       const Item *item,
+                                       bool is_eq_func) const
+{
+  return is_eq_func ?
+         cmp_to_string_with_stricter_collation(cond, item) :
+         cmp_to_string_with_same_collation(cond, item);
+}
+
+
 /**
   This overrides the default behavior of the parent constructor
   Warn_filter(thd) to suppress notes about trailing spaces in case of CHAR(N),
@@ -8461,6 +8484,14 @@ Field::geometry_type Field_geom::geometry_type_merge(geometry_type a,
   return Field::GEOM_GEOMETRY;
 }
 
+
+bool Field_geom::can_optimize_range(const Item_bool_func *cond,
+                                    const Item *item,
+                                    bool is_eq_func) const
+{
+  return item->cmp_type() == STRING_RESULT;
+}
+
 #endif /*HAVE_SPATIAL*/
 
 /****************************************************************************

sql/field.h

@@ -1199,16 +1199,6 @@ public:
   { return binary() ? &my_charset_bin : charset(); }
   virtual CHARSET_INFO *sort_charset(void) const { return charset(); }
   virtual bool has_charset(void) const { return FALSE; }
-  /*
-    match_collation_to_optimize_range() is to distinguish in
-    range optimizer (see opt_range.cc) between real string types:
-      CHAR, VARCHAR, TEXT
-    and the other string-alike types with result_type() == STRING_RESULT:
-      DATE, TIME, DATETIME, TIMESTAMP
-    We need it to decide whether to test if collation of the operation
-    matches collation of the field (needed only for real string types).
-  */
-  virtual bool match_collation_to_optimize_range() const { return false; }
   virtual void set_charset(CHARSET_INFO *charset_arg) { }
   virtual enum Derivation derivation(void) const
   { return DERIVATION_IMPLICIT; }
@@ -1359,6 +1349,15 @@ public:
   }
   virtual bool can_optimize_group_min_max(const Item_bool_func *cond,
                                           const Item *const_item) const;
+  /**
+    Test if Field can use range optimizer for a standard comparison operation:
+      <=, <, =, <=>, >, >=
+    Note, this method does not cover spatial operations.
+  */
+  virtual bool can_optimize_range(const Item_bool_func *cond,
+                                  const Item *item,
+                                  bool is_eq_func) const;
+
   bool can_optimize_outer_join_table_elimination(const Item_bool_func *cond,
                                                  const Item *item) const
   {
@@ -1583,13 +1582,15 @@ public:
 
   int store_decimal(const my_decimal *d);
   uint32 max_data_length() const;
-  bool match_collation_to_optimize_range() const { return true; }
   bool can_optimize_keypart_ref(const Item_bool_func *cond,
                                 const Item *item) const;
   bool can_optimize_hash_join(const Item_bool_func *cond,
                               const Item *item) const;
   bool can_optimize_group_min_max(const Item_bool_func *cond,
                                   const Item *const_item) const;
+  bool can_optimize_range(const Item_bool_func *cond,
+                          const Item *item,
+                          bool is_eq_func) const;
 };
 
 /* base class for float and double and decimal (old one) */
@@ -2082,6 +2083,12 @@ public:
                                 const Item *item) const;
   bool can_optimize_group_min_max(const Item_bool_func *cond,
                                   const Item *const_item) const;
+  bool can_optimize_range(const Item_bool_func *cond,
+                                  const Item *item,
+                                  bool is_eq_func) const
+  {
+    return true;
+  }
 };
 
 
@@ -3101,7 +3108,9 @@ public:
   { geom_type= geom_type_arg; srid= 0; }
   enum ha_base_keytype key_type() const { return HA_KEYTYPE_VARBINARY2; }
   enum_field_types type() const { return MYSQL_TYPE_GEOMETRY; }
-  bool match_collation_to_optimize_range() const { return false; }
+  bool can_optimize_range(const Item_bool_func *cond,
+                                  const Item *item,
+                                  bool is_eq_func) const;
   void sql_type(String &str) const;
   int  store(const char *to, uint length, CHARSET_INFO *charset);
   int  store(double nr);

sql/opt_range.cc

@@ -7849,28 +7849,6 @@ Item_bool_func::get_mm_leaf(RANGE_OPT_PARAM *param,
   if (key_part->image_type != Field::itRAW)
     DBUG_RETURN(0);   // e.g. SPATIAL index
 
-  /*
-    1. Usually we can't use an index if the column collation
-       differ from the operation collation.
-
-    2. However, we can reuse a case insensitive index for
-       the binary searches:
-
-       WHERE latin1_swedish_ci_column = 'a' COLLATE lati1_bin;
-
-       WHERE latin1_swedish_ci_colimn = BINARY 'a '
-
-  */
-  if (field->result_type() == STRING_RESULT &&
-      field->match_collation_to_optimize_range() &&
-      value->result_type() == STRING_RESULT &&
-      field->charset() != compare_collation() &&
-      !((type == EQUAL_FUNC || type == EQ_FUNC) &&
-        compare_collation()->state & MY_CS_BINSORT))
-    goto end;
-  if (value->cmp_type() == TIME_RESULT && field->cmp_type() != TIME_RESULT)
-    goto end;
-
   if (param->using_real_indexes &&
       !field->optimize_range(param->real_keynr[key_part->key],
                              key_part->part) &&
@@ -7878,12 +7856,10 @@ Item_bool_func::get_mm_leaf(RANGE_OPT_PARAM *param,
       type != EQUAL_FUNC)
     goto end;                                   // Can't optimize this
 
-  /*
-    We can't always use indexes when comparing a string index to a number
-    cmp_type() is checked to allow compare of dates to numbers
-  */
-  if (field->cmp_type() == STRING_RESULT && value->cmp_type() != STRING_RESULT)
+  if (!field->can_optimize_range(this, value,
+                                 type == EQUAL_FUNC || type == EQ_FUNC))
     goto end;
+
   err= value->save_in_field_no_warnings(field, 1);
   if (err == 2 && field->cmp_type() == STRING_RESULT)
   {