Method insert_on_duplicate_update

sql/sql_insert.cc:2235–2372

int Write_record::insert_on_duplicate_update(ha_rows *inserted,
                                             ha_rows *updated)
{
  int res= table->file->ha_write_row(table->record[0]);
  if (likely(!res))
    return after_insert(inserted);

  res=prepare_handle_duplicate(res);
  if (unlikely(res))
    return restore_on_error();

  ulonglong prev_insert_id_for_cur_row= 0;
  /*
    We don't check for other UNIQUE keys - the first row
    that matches, is updated. If update causes a conflict again,
    an error is returned
  */
  DBUG_ASSERT(table->insert_values != NULL);
  store_record(table,insert_values);
  restore_record(table,record[1]);
  table->reset_default_fields();

  /*
    in INSERT ... ON DUPLICATE KEY UPDATE the set of modified fields can
    change per row. Thus, we have to do reset_default_fields() per row.
    Twice (before insert and before update).
  */
  DBUG_ASSERT(info->update_fields->elements ==
              info->update_values->elements);

  bool trg_skip_row= false;
  if (fill_record_n_invoke_before_triggers(thd, table,
                                           *info->update_fields,
                                           *info->update_values,
                                           info->ignore,
                                           TRG_EVENT_UPDATE,
                                           &trg_skip_row))
    return restore_on_error();

  if (trg_skip_row)
    return 0;

  bool different_records= (!records_are_comparable(table) ||
                           compare_record(table));
  /*
    Default fields must be updated before checking view updateability.
    This branch of INSERT is executed only when a UNIQUE key was violated
    with the ON DUPLICATE KEY UPDATE option. In this case the INSERT
    operation is transformed to an UPDATE, and the default fields must
    be updated as if this is an UPDATE.
  */
  if (different_records && table->default_field)
    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);
  if (unlikely(res))
  {