cleanup: on update default now

* remove one level of virtual functions
* remove redundant checks
* remove an if() as the value is always known at compilation time

don't pretend that "DEFAULT expr" and "ON UPDATE DEFAULT NOW"
are "basically the same thing"

sql/field.h

@@ -992,14 +992,6 @@ class Field: public Value_source
   }
   bool set_explicit_default(Item *value);
 
-  /**
-     Evaluates the @c UPDATE default function, if one exists, and stores the
-     result in the record buffer. If no such function exists for the column,
-     or the function is not valid for the column's data type, invoking this
-     function has no effect.
-  */
-  virtual int evaluate_update_default_function() { return 0; }
-
   virtual bool binary() const { return 1; }
   virtual bool zero_pack() const { return 1; }
   virtual enum ha_base_keytype key_type() const { return HA_KEYTYPE_BINARY; }
@@ -2519,13 +2511,6 @@ class Field_timestamp :public Field_temporal {
   void sql_type(String &str) const;
   bool zero_pack() const { return 0; }
   int set_time();
-  int evaluate_update_default_function()
-  {
-    int res= 0;
-    if (has_update_default_function())
-      res= set_time();
-    return res;
-  }
   /* Get TIMESTAMP field value as seconds since begging of Unix Epoch */
   virtual my_time_t get_timestamp(const uchar *pos, ulong *sec_part) const;
   my_time_t get_timestamp(ulong *sec_part) const
@@ -2954,13 +2939,6 @@ class Field_datetime :public Field_temporal_with_date {
   bool get_date(MYSQL_TIME *ltime, ulonglong fuzzydate)
   { return Field_datetime::get_TIME(ltime, ptr, fuzzydate); }
   int set_time();
-  int evaluate_update_default_function()
-  {
-    int res= 0;
-    if (has_update_default_function())
-      res= set_time();
-    return res;
-  }
   uchar *pack(uchar* to, const uchar *from,
               uint max_length __attribute__((unused)))
   {

sql/sql_base.cc

@@ -8072,7 +8072,7 @@ fill_record(THD *thd, TABLE *table_arg, List<Item> &fields, List<Item> &values,
   }
 
   if (!update && table_arg->default_field &&
-      table_arg->update_default_fields(0, ignore_errors))
+      table_arg->update_default_fields(ignore_errors))
     goto err;
   /* Update virtual fields */
   if (table_arg->vfield &&
@@ -8317,7 +8317,7 @@ fill_record(THD *thd, TABLE *table, Field **ptr, List<Item> &values,
     all_fields_have_values &= field->set_explicit_default(value);
   }
   if (!all_fields_have_values && table->default_field &&
-      table->update_default_fields(0, ignore_errors))
+      table->update_default_fields(ignore_errors))
     goto err;
   /* Update virtual fields */
   thd->abort_on_warning= FALSE;

sql/sql_insert.cc

@@ -1796,10 +1796,7 @@ int write_record(THD *thd, TABLE *table,COPY_INFO *info)
           be updated as if this is an UPDATE.
         */
         if (different_records && table->default_field)
-        {
-          if (table->update_default_fields(1, info->ignore))
-            goto err;
-        }
+          table->evaluate_update_default_function();
 
         /* CHECK OPTION for VIEW ... ON DUPLICATE KEY UPDATE ... */
         res= info->table_list->view_check_option(table->in_use, info->ignore);
@@ -3762,7 +3759,7 @@ int select_insert::send_data(List<Item> &values)
 
   thd->count_cuted_fields= CHECK_FIELD_WARN;	// Calculate cuted fields
   store_values(values);
-  if (table->default_field && table->update_default_fields(0, info.ignore))
+  if (table->default_field && table->update_default_fields(info.ignore))
     DBUG_RETURN(1);
   thd->count_cuted_fields= CHECK_FIELD_ERROR_FOR_NULL;
   if (thd->is_error())

sql/sql_table.cc

@@ -9455,7 +9455,7 @@ do_continue:;
     /* Check that we can call default functions with default field values */
     altered_table->reset_default_fields();
     if (altered_table->default_field &&
-        altered_table->update_default_fields(0, 1))
+        altered_table->update_default_fields(true))
       goto err_new_table_cleanup;
 
     // Ask storage engine whether to use copy or in-place
@@ -10138,7 +10138,7 @@ copy_data_between_tables(THD *thd, TABLE *from, TABLE *to,
     }
     prev_insert_id= to->file->next_insert_id;
     if (to->default_field)
-      to->update_default_fields(0, ignore);
+      to->update_default_fields(ignore);
     if (to->vfield)
       to->update_virtual_fields(to->file, VCOL_UPDATE_FOR_WRITE);
 

sql/sql_update.cc

@@ -761,11 +761,8 @@ int mysql_update(THD *thd,
 
       if (!can_compare_record || compare_record(table))
       {
-        if (table->default_field && table->update_default_fields(1, ignore))
-        {
-          error= 1;
-          break;
-        }
+        if (table->default_field)
+          table->evaluate_update_default_function();
         if ((res= table_list->view_check_option(thd, ignore)) !=
             VIEW_CHECK_OK)
         {
@@ -2156,8 +2153,8 @@ int multi_update::send_data(List<Item> &not_used_values)
       {
 	int error;
 
-        if (table->default_field && table->update_default_fields(1, ignore))
-          DBUG_RETURN(1);
+        if (table->default_field)
+          table->evaluate_update_default_function();
 
         if ((error= cur_table->view_check_option(thd, ignore)) !=
             VIEW_CHECK_OK)
@@ -2482,9 +2479,8 @@ int multi_update::do_updates()
       if (!can_compare_record || compare_record(table))
       {
         int error;
-        if (table->default_field &&
-            (error= table->update_default_fields(1, ignore)))
-          goto err2;
+        if (table->default_field)
+          table->evaluate_update_default_function();
         if (table->vfield &&
             table->update_virtual_fields(table->file, VCOL_UPDATE_FOR_WRITE))
           goto err2;

sql/table.cc

@@ -7736,7 +7736,7 @@ int TABLE::update_virtual_field(Field *vf)
          ignore_errors == 0. If set then an error was generated.
 */
 
-int TABLE::update_default_fields(bool update_command, bool ignore_errors)
+int TABLE::update_default_fields(bool ignore_errors)
 {
   Query_arena backup_arena;
   Field **field_ptr;
@@ -7755,15 +7755,10 @@ int TABLE::update_default_fields(bool update_command, bool ignore_errors)
       do not update the field with its automatic default value.
     */
     if (!field->has_explicit_value())
-    {
-      if (!update_command)
     {
       if (field->default_value &&
           (field->default_value->flags || field->flags & BLOB_FLAG))
         res|= (field->default_value->expr->save_in_field(field, 0) < 0);
-      }
-      else
-        res|= field->evaluate_update_default_function();
       if (!ignore_errors && res)
       {
         my_error(ER_CALCULATING_DEFAULT_VALUE, MYF(0), field->field_name);
@@ -7776,6 +7771,21 @@ int TABLE::update_default_fields(bool update_command, bool ignore_errors)
   DBUG_RETURN(res);
 }
 
+void TABLE::evaluate_update_default_function()
+{
+  DBUG_ENTER("TABLE::evaluate_update_default_function");
+
+  if (s->has_update_default_function)
+    for (Field **field_ptr= default_field; *field_ptr ; field_ptr++)
+    {
+      Field *field= (*field_ptr);
+      if (!field->has_explicit_value() && field->has_update_default_function())
+        field->set_time();
+    }
+  DBUG_VOID_RETURN;
+}
+
+
 /**
    Reset markers that fields are being updated
 */

sql/table.h

@@ -1453,7 +1453,8 @@ struct TABLE
   ulong actual_key_flags(KEY *keyinfo);
   int update_virtual_field(Field *vf);
   int update_virtual_fields(handler *h, enum_vcol_update_mode update_mode);
-  int update_default_fields(bool update, bool ignore_errors);
+  int update_default_fields(bool ignore_errors);
+  void evaluate_update_default_function();
   void reset_default_fields();
   inline ha_rows stat_records() { return used_stat_records; }