(PECL mongo >=1.2.11)
MongoCursor::awaitData — Sets whether this cursor will wait for a while for a tailable cursor to return more data
This method is to be used with tailable cursors. If we are at the end of the data, block for a while rather than returning no data. After a timeout period, we do return as normal.
wait
If the cursor should wait for more data to become available.
Returns this cursor.
Throws MongoCursorException if this cursor has started iterating.
Przykład #1 MongoCursor::awaitData() example
In this example we tail the "oplog" and instead of sleeping during every iteration, we set the MongoCursor::awaitData() option. MongoCursor::hasNext() will now block until there is more data available.
<?php
$m = new MongoClient( 'mongodb://localhost:13000', array( 'replSet' => 'seta' ) );
$c = $m->local->selectCollection( 'oplog.rs' );
$cursor = $c->find( array( 'ns' => 'demo.article', 'op' => 'i' ) );
$cursor->tailable( true );
$cursor->awaitData( true );
while (true) {
if (!$cursor->hasNext()) {
// we've read all the results, exit
if ($cursor->dead()) {
break;
}
} else {
var_dump( $cursor->getNext() );
}
}
?>
MongoDB core docs on » tailable cursors.