Code to queue sales grid updates

Observer.php

<?php
class Aoe_QueuedOperations_Model_Observer
{
    /**
    * This is used to queue the sales grid updates
    * 
    * NB: This should be attached to the sales_order_resource_update_grid_records event
    * 
    *
    * @see Mage_Sales_Model_Resource_Order_Abstract::updateGridRecords
    */
    public function queueSalesGridUpdate(Varien_Event_Observer $observer)
    {
        if (!Mage::getStoreConfigFlag('aoe/queued_operations/sales_grid_updates')) {
            return;
        }

        /** @var Varien_Object $proxy */
        $proxy = $observer->getProxy();
        if (!$proxy instanceof Varien_Object) {
            return;
        }

        /** @var Mage_Sales_Model_Resource_Order_Abstract $resource */
        $resource = $proxy->getResource();
        if ($resource instanceof Mage_Sales_Model_Resource_Order) {
            $resourceName = 'sales/order';
        } else {
            return;
        }
    
        $ids = $proxy->getIds();
        if (!is_array($ids)) {
            return;
        }
    
        $ids = array_filter(array_map('intval', $ids));
        if (empty($ids)) {
            return;
        }

        try {
            /** @var Aoe_Queue_Model_Queue $queue */
            $queue = Mage::getModel('aoe_queue/queue', 'sales_grid_updates');
            $queue->addTask('Aoe_QueuedOperations/Observer::processSalesGridUpdate', array($resourceName, $ids));
            $proxy->setIds(array());
        } catch (Exception $e) {
            Mage::logException($e);
        }
    }
    
    /**
    * This is used to processed queued sales grid updates
    *
    * @param string $resource
    * @param int[]  $ids
    *
    * @see Mage_Sales_Model_Resource_Order_Abstract::updateGridRecords
    * @see Aoe_QueuedOperations_Model_Observer::queueSalesGridUpdate
    */
    public function processSalesGridUpdate($resource, array $ids)
    {
        if (empty($resource) || empty($ids)) {
            Mage::throwException('Invalid callback parameters');
        }
    
        /** @var Mage_Sales_Model_Resource_Order_Abstract $resource */
        $resource = Mage::getResourceModel($resource);
        if (!$resource instanceof Mage_Sales_Model_Resource_Order_Abstract) {
            Mage::throwException('Invalid resource parameter');
        }
    
        $ids = array_filter(array_map('intval', $ids));
        if (empty($ids)) {
            return;
        }
    
        $columnsToSelect = array();
        $table = $resource->getGridTable();
        $select = $resource->getUpdateGridRecordsSelect($ids, $columnsToSelect);
        $select->getAdapter()->query($select->insertFromSelect($table, $columnsToSelect, true));
        
        return;
    }
}