Large Collection Exhausting Memory

[AjithChandran]

I am writing an admin module. I created a collection and if the number of rows in the table are small it loads fine. Ultimately the table will have 250k rows in it and when I attempt to load the collection it exhausts memory. I was under the impression that Magento would lazy load collections. I also will probably need to know how to use the resource iterator in mage 2 as well. I can provide code samples but there is little more than a basic module skeleton at this point. I would greatly appreciate a code example of how to handle and iterate through a large collection.

Note: the collection is pulling from a custom table

[heatertreater]

You can page through a large collection like this:

$collection->setPageSize(15);
$pages = $collection->getLastPageNumber();
for ($pageNum = 1; $pageNum<=$pages; $pageNum++) {
    $collection->setCurPage($pageNum);
    foreach ($collection as $item) {
        //Do something.
    }
    $collection->clear();
}