在同一个集合上更新时mongo游标会受到影响吗？

Question

I have some code like following,

$query = array("vid"=>"just_a_video_key_and_can_be_any_string");
$set = array("$set" => array("attr" => "attr_value"));
$cursor = $collection->find();
$cursor = $cursor->batchSize(500);
foreach ($cursor as $item) {
    $collection->update($query, $set)
}

I find the loop times is 500, while the $collection has 20K+ documents.

The update operation only update one document, not involving delete or insert.

My question is why the foreach loop only 500 times(which is the number of batch size) while the total documents in the database is more than 20K?

Answer 1

If I'm understanding you correctly, you're confused about why mongodb is only updating one document.

Mongodb only updates one document at a time. To update all documents which match your query, pass the multiple option to mongodb via 'multiple' => true. See https://stackoverflow.com/a/15691466/2416049