MDEV-18501 Partition pruning doesn't work for historical queries (cleanup)

Cleanup removes useless allocation.

sql/partition_info.cc

@@ -1473,15 +1473,8 @@ void partition_info::print_no_partition_found(TABLE *table_arg, myf errflag)
     FALSE                     Success
 */
 
-bool partition_info::set_part_expr(THD *thd, char *start_token, Item *item_ptr,
-                                   char *end_token, bool is_subpart)
+bool partition_info::set_part_expr(THD *thd, Item *item_ptr, bool is_subpart)
 {
-  size_t expr_len= end_token - start_token;
-  char *func_string= (char*) thd->memdup(start_token, expr_len);
-
-  if (unlikely(!func_string))
-    return TRUE;
-
   if (is_subpart)
   {
     list_of_subpart_fields= FALSE;

sql/partition_info.h

@@ -366,8 +366,7 @@ public:
   void init_col_val(part_column_list_val *col_val, Item *item);
   int reorganize_into_single_field_col_val(THD *thd);
   part_column_list_val *add_column_value(THD *thd);
-  bool set_part_expr(THD *thd, char *start_token, Item *item_ptr,
-                     char *end_token, bool is_subpart);
+  bool set_part_expr(THD *thd, Item *item_ptr, bool is_subpart);
   bool set_up_charset_field_preps(THD *thd);
   bool check_partition_field_length();
   bool init_column_part(THD *thd);

sql/sql_yacc.yy

@@ -5541,10 +5541,10 @@ part_column_list:
 
 
 part_func:
-          '(' remember_name part_func_expr remember_end ')'
+          '(' part_func_expr ')'
           {
             partition_info *part_info= Lex->part_info;
-            if (unlikely(part_info->set_part_expr(thd, $2 + 1, $3, $4, FALSE)))
+            if (unlikely(part_info->set_part_expr(thd, $2, FALSE)))
               MYSQL_YYABORT;
             part_info->num_columns= 1;
             part_info->column_list= FALSE;
@@ -5552,9 +5552,9 @@ part_func:
         ;
 
 sub_part_func:
-          '(' remember_name part_func_expr remember_end ')'
+          '(' part_func_expr ')'
           {
-            if (unlikely(Lex->part_info->set_part_expr(thd, $2 + 1, $3, $4, TRUE)))
+            if (unlikely(Lex->part_info->set_part_expr(thd, $2, TRUE)))
               MYSQL_YYABORT;
           }
         ;

sql/sql_yacc_ora.yy

@@ -5387,10 +5387,10 @@ part_column_list:
 
 
 part_func:
-          '(' remember_name part_func_expr remember_end ')'
+          '(' part_func_expr ')'
           {
             partition_info *part_info= Lex->part_info;
-            if (unlikely(part_info->set_part_expr(thd, $2 + 1, $3, $4, FALSE)))
+            if (unlikely(part_info->set_part_expr(thd, $2, FALSE)))
               MYSQL_YYABORT;
             part_info->num_columns= 1;
             part_info->column_list= FALSE;
@@ -5398,9 +5398,9 @@ part_func:
         ;
 
 sub_part_func:
-          '(' remember_name part_func_expr remember_end ')'
+          '(' part_func_expr ')'
           {
-            if (unlikely(Lex->part_info->set_part_expr(thd, $2 + 1, $3, $4, TRUE)))
+            if (unlikely(Lex->part_info->set_part_expr(thd, $2, TRUE)))
               MYSQL_YYABORT;
           }
         ;