MongoCollection::parallelCollectionScan

(PECL mongo >=1.5.0)

MongoCollection::parallelCollectionScan — Returns an array of cursors to iterator over a full collection in parallel

说明

public array[MongoCommandCursor] MongoCollection::parallelCollectionScan ( int $num_cursors )

This method returns an array of a maximum of num_cursors cursors. An iteration over one of the returned cursors results in a partial set of documents for a collection. Iteration over all the returned cursors results in getting every document back from the collection.

This method is a wrapper for the parallelCollectionScan MongoDB command.

参数

num_cursors: The number of cursors to request from the server. Please note, that the server can return less cursors than you requested.

返回值

Returns an array of MongoCommandCursor objects.

范例

Example #1 MongoCollection::parallelCollectionScan() example

Returning all documents in a collection by using multiple cursors.

  <?php
$m  = new  MongoClient ;
 $c  =  $m -> demo -> cities ;

 
 $cursors  =  $c -> parallelCollectionScan (  3  );

 
 $mi  = new  MultipleIterator (  MultipleIterator :: MIT_NEED_ANY  );
foreach (  $cursors  as  $cursor  )
{
     $mi -> attachIterator (  $cursor  );
}

 
 foreach (  $mi  as  $items  )
{
    foreach (  $items  as  $item  )
    {
        if (  $item  !==  NULL  )
        {
            echo  $item [ 'name' ],  "\n" ;
        }
    }
}
 ?>

参见

MultipleIterator
MongoCommandCursor
MongoDB::command() - 执行一条 Mongo 指令