liciagbar/application/core/MY_DB_mysqli_driver.php

<?php
class MY_DB_mysqli_driver extends CI_DB_mysqli_driver
{

    final public function __construct($params)
    {
        parent::__construct($params);
    }

    /**
     * Insert_On_Duplicate_Update_Batch
     *
     * Compiles batch insert strings and runs the queries
     * MODIFIED to do a MySQL 'ON DUPLICATE KEY UPDATE'
     *
     * @access public
     * @param string the table to retrieve the results from
     * @param array an associative array of insert values
     * @return object
     */
    public function insert_on_duplicate_update_batch($table = '', $set = null)
    {
        if (!is_null($set)) {
            $this->set_insert_batch($set);
        }

        if (count($this->qb_set) == 0) {
            if ($this->db_debug) {
                //No valid data array.  Folds in cases where keys and values did not match up
                return $this->display_error('db_must_use_set');
            }
            return false;
        }

        if ($table == '') {
            if (!isset($this->qb_from[0])) {
                if ($this->db_debug) {
                    return $this->display_error('db_must_set_table');
                }
                return false;
            }

            $table = $this->qb_from[0];
        }

        // Batch this baby
        for ($i = 0, $total = count($this->qb_set); $i < $total; $i = $i + 5000) {

            $sql = $this->_insert_on_duplicate_update_batch($this->protect_identifiers($table, true, null, false), $this->qb_keys, array_slice($this->qb_set, $i, 5000));

            // echo $sql;

            $this->query($sql);
        }

        $this->_reset_write();

        return true;
    }

    /**
     * Insert_on_duplicate_update_batch statement
     *
     * Generates a platform-specific insert string from the supplied data
     * MODIFIED to include ON DUPLICATE UPDATE
     *
     * @access public
     * @param string the table name
     * @param array the insert keys
     * @param array the insert values
     * @return string
     */
    private function _insert_on_duplicate_update_batch($table, $keys, $values)
    {
        foreach ($keys as $key) {
            $update_fields[] = $key . '=VALUES(' . $key . ')';
        }

        return "INSERT INTO " . $table . " (" . implode(', ', $keys) . ") VALUES " . implode(', ', $values) . " ON DUPLICATE KEY UPDATE " . implode(', ', $update_fields);
    }

}