Removing "DTCollation Arg_comparator::cmp_collation".

Using a CHARSET_INFO pointer instead.

Author: Alexander Barkov

sql/item_cmpfunc.cc

@@ -494,10 +494,13 @@ bool Item_func::setup_args_and_comparator(THD *thd, Arg_comparator *cmp)
   DBUG_ASSERT(arg_count >= 2); // Item_func_nullif has arg_count == 3
 
   if (args[0]->cmp_type() == STRING_RESULT &&
-      args[1]->cmp_type() == STRING_RESULT &&
-      agg_arg_charsets_for_comparison(cmp->cmp_collation, args, 2))
+      args[1]->cmp_type() == STRING_RESULT)
+  {
+    DTCollation tmp;
+    if (agg_arg_charsets_for_comparison(tmp, args, 2))
       return true;
-
+    cmp->m_compare_collation= tmp.collation;
+  }
   //  Convert constants when compared to int/year field
   DBUG_ASSERT(functype() != LIKE_FUNC);
   convert_const_compared_to_int_field(thd);
@@ -528,7 +531,7 @@ int Arg_comparator::set_compare_func(Item_func_or_sum *item, Item_result type)
 
   switch (type) {
   case TIME_RESULT:
-    cmp_collation.collation= &my_charset_numeric;
+    m_compare_collation= &my_charset_numeric;
     break;
   case ROW_RESULT:
   {
@@ -666,17 +669,19 @@ bool get_mysql_time_from_str(THD *thd, String *str, timestamp_type warn_type,
 */
 bool Arg_comparator::agg_arg_charsets_for_comparison()
 {
-  if (cmp_collation.set((*a)->collation, (*b)->collation, MY_COLL_CMP_CONV) ||
-      cmp_collation.derivation == DERIVATION_NONE)
+  DTCollation tmp;
+  if (tmp.set((*a)->collation, (*b)->collation, MY_COLL_CMP_CONV) ||
+      tmp.derivation == DERIVATION_NONE)
   {
     my_coll_agg_error((*a)->collation, (*b)->collation, owner->func_name());
     return true;
   }
-  if (agg_item_set_converter(cmp_collation, owner->func_name(),
+  if (agg_item_set_converter(tmp, owner->func_name(),
                              a, 1, MY_COLL_CMP_CONV, 1) ||
-      agg_item_set_converter(cmp_collation, owner->func_name(),
+      agg_item_set_converter(tmp, owner->func_name(),
                              b, 1, MY_COLL_CMP_CONV, 1))
     return true;
+  m_compare_collation= tmp.collation;
   return false;
 }
 
@@ -909,7 +914,7 @@ int Arg_comparator::compare_string()
     {
       if (set_null)
         owner->null_value= 0;
-      return sortcmp(res1,res2,cmp_collation.collation);
+      return sortcmp(res1, res2, compare_collation());
     }
   }
   if (set_null)
@@ -930,7 +935,7 @@ int Arg_comparator::compare_e_string()
   res2= (*b)->val_str(&value2);
   if (!res1 || !res2)
     return MY_TEST(res1 == res2);
-  return MY_TEST(sortcmp(res1, res2, cmp_collation.collation) == 0);
+  return MY_TEST(sortcmp(res1, res2, compare_collation()) == 0);
 }
 
 

sql/item_cmpfunc.h

@@ -48,6 +48,7 @@ class Arg_comparator: public Sql_alloc
 {
   Item **a, **b;
   Item_result m_compare_type;
+  CHARSET_INFO *m_compare_collation;
   arg_cmp_func func;
   Item_func_or_sum *owner;
   bool set_null;                   // TRUE <=> set owner->null_value
@@ -65,16 +66,18 @@ class Arg_comparator: public Sql_alloc
   int compare_e_temporal(enum_field_types type);
 
 public:
-  DTCollation cmp_collation;
   /* Allow owner function to use string buffers. */
   String value1, value2;
 
   Arg_comparator(): m_compare_type(STRING_RESULT),
+    m_compare_collation(&my_charset_bin),
     set_null(TRUE), comparators(0), thd(0),
     a_cache(0), b_cache(0) {};
   Arg_comparator(Item **a1, Item **a2): a(a1), b(a2),
-    m_compare_type(STRING_RESULT), set_null(TRUE),
-    comparators(0), thd(0), a_cache(0), b_cache(0) {};
+    m_compare_type(STRING_RESULT),
+    m_compare_collation(&my_charset_bin),
+    set_null(TRUE), comparators(0), thd(0),
+    a_cache(0), b_cache(0) {};
 
 public:
   inline int set_cmp_func(Item_func_or_sum *owner_arg,
@@ -115,6 +118,7 @@ class Arg_comparator: public Sql_alloc
            ((Item_func*)owner)->functype() == Item_func::EQUAL_FUNC);
   }
   Item_result compare_type() const { return m_compare_type; }
+  CHARSET_INFO *compare_collation() const { return m_compare_collation; }
   Arg_comparator *subcomparators() const { return comparators; }
   void cleanup()
   {
@@ -401,8 +405,7 @@ class Item_bool_rowready_func2 :public Item_bool_func2
   {
     return cmp.set_cmp_func(this, tmp_arg, tmp_arg + 1, true);
   }
-  CHARSET_INFO *compare_collation() const
-  { return cmp.cmp_collation.collation; }
+  CHARSET_INFO *compare_collation() const { return cmp.compare_collation(); }
   Item_result compare_type() const { return cmp.compare_type(); }
   Arg_comparator *get_comparator() { return &cmp; }
   void cleanup()
@@ -931,7 +934,7 @@ class Item_func_nullif :public Item_func_hybrid_field_type
   bool is_null();
   Item* propagate_equal_fields(THD *thd, const Context &ctx, COND_EQUAL *cond)
   {
-    Context cmpctx(ANY_SUBST, cmp.compare_type(), cmp.cmp_collation.collation);
+    Context cmpctx(ANY_SUBST, cmp.compare_type(), cmp.compare_collation());
     args[0]->propagate_equal_fields_and_change_item_tree(thd, cmpctx,
                                                          cond, &args[0]);
     args[1]->propagate_equal_fields_and_change_item_tree(thd, cmpctx,

sql/sql_select.cc

@@ -12766,7 +12766,7 @@ static bool check_row_equality(THD *thd, const Arg_comparator *comparators,
       is_converted= check_simple_equality(thd,
                                           Item::Context(Item::ANY_SUBST,
                                                         tmp->compare_type(),
-                                                 tmp->cmp_collation.collation),
+                                                  tmp->compare_collation()),
                                           left_item, right_item,
                                           cond_equal);
     }