MongoDB + PHP: How do you query object sizes? - php

Question

MongoDB + PHP: How do you query the size of a document stored in a mongodb object? The document limit, at the time of this writing (recently raised from 4MB), is 16MB.
How can I query the size of a Document using the ObjectId?

Answer 1

Object.bsonsize(document) is the function you're after. I'm reading this thread and finding a few suggestions about how to do it in php. The easiest is probably to query for the document object and run strlen on the bson_encode'd object giving you the size in bytes.
$byteSize = strlen( bson_encode( $yourDocument ) );
If you're wanting to do this check on a lot of documents, say in a loop, without reading back every document you'll need to run a command execute (Mardix had posted this little function to do just that - note: it could easily be rewritten a little better to avoid the hardcoded and global variables):
$DBName = "MyDBName";
$MongoDB = new MongoDB(new Mongo(),$DBName);
function documentSize(Array $Criteria){
global $MongoDB;
$collectionName = "MyCollection";
$jsonCriteria = json_encode($Criteria);
$code = "function(){
return Object.bsonsize(db.{$collectionName}.findOne({$jsonCriteria}))
}";
$resp = $MongoDB->execute($code);
return $resp["retval"];
}
PHP example where $id is the document id
$myDocSize = documentSize(array("_id"=>$id));