MongoCursor
PHP Manual

MongoCursor::awaitData

Sets whether this cursor will wait for a while for a tailable cursor to return more data

Description

public MongoCursor MongoCursor::awaitData ([ bool $wait = true ] )

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.

Parameters

wait

If the cursor should wait for more data to become available.

Return Values

Returns this cursor.

Errors/Exceptions

Throws MongoCursorException if this cursor has started iterating.

Examples

Example #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() );
    }
}
?>

See Also

MongoDB core docs on » tailable cursors.

  • MongoCursor::tailable