如何使用codeigniter优化活动记录？

i have a problem whit a error: maximum size of arrays in php, $ids has a maximum and i don't know how to resolve it. Array size is limited only by amount of memory your server has. I 'll get out of memory" error and i can not change php.ini I need optimize this funcctions, some idea ?

function delete_ScormByIdPlataforma($idPlatforma)
    {       
        if ($this->getIdScormVarsToDelete($idPlatforma) != 0)
        {
            $ids = $this->getIdScormVarsToDelete($idPlatforma);
            $this->db->where_in('ID_dispatch', $ids);
            $this->db->delete('scormvars');
        }//else
        //log_message('error', 'No se han encontrado scorms a borrar'.$this->db->_error_message().' - '.$this->db->last_query());
    }



function getIdScormVarsToDelete($idPlataforma)
    {
        $this->db->select('s.ID_dispatch');
        $this->db->from('scormvars as s');
        $this->db->join('dispatch as d', 's.ID_dispatch = d.ID_dispatch', 'INNER');
        $this->db->join('licencias as l', 'd.ID_licencia = l.ID_licencia','INNER');
        $this->db->where('l.id_plataforma', $idPlataforma);

        $query = $this->db->get();

        if($query)
        {
            if($query->num_rows()>0){
                foreach ($query->result() as $fila){
                    $data[] = $fila->ID_dispatch;
                }
                return array_unique($data);
            }
        }
        else
        {
            //log_message('error', 'No se han encontrado Dispatch a borrar'.$this->db->_error_message().' - '.$this->db->last_query());
            return 0;
        }
    }

It's in way you pass data and way you write codes. So If there are lot of joins or some bigger function you can switch it to SP(Stored Procedure).

And you can check your query speed by

Enable Profiler in your __construct

$this->output->enable_profiler(TRUE);

And in your code

$this->benchmark->mark('my_mark_start'); # my_mark_start can set any name with _start/ generate_start
$data['some_name'] = $this->model_name->modelFunctionName();
$this->benchmark->mark('my_mark_end'); # generate_end

This will shows how much your code took took to proceed the data

You don't need to edit the php.ini file to increase the memory limit. You can set a new memory limit at runtime inside your script, using ini_set():

<?php
ini_set('memory_limit', '256M');

// From here on, the memory limit will be 256M.