Function compute_next_insert_id

sql/handler.cc:4386–4412

Generate the next auto-increment number based on increment and offset. computes the lowest number - strictly greater than "nr" - of the form: auto_increment_offset + N * auto_increment_increment If overflow happened then return MAX_ULONGLONG value as an indication of overflow. In most cases increment= offset= 1, in which case we get: @verbatim 1,2,3,4,5,... @endverbatim If increm

  @verbatim 1,5,15,25,35,... @endverbatim
*/
inline ulonglong
compute_next_insert_id(ulonglong nr,struct system_variables *variables)
{
  const ulonglong save_nr= nr;

  if (variables->auto_increment_increment == 1)
    nr= nr + 1; // optimization of the formula below
  else
  {
    /*
       Calculating the number of complete auto_increment_increment extents:
    */
    nr= (nr + variables->auto_increment_increment -
         variables->auto_increment_offset) /
        (ulonglong) variables->auto_increment_increment;
    /*
       Adding an offset to the auto_increment_increment extent boundary:
    */
    nr= nr * (ulonglong) variables->auto_increment_increment +
        variables->auto_increment_offset;
  }

  if (unlikely(nr <= save_nr))
    return ULONGLONG_MAX;

  return nr;
}


void handler::adjust_next_insert_id_after_explicit_value(ulonglong nr)