(PECL mongo >=1.3.3)
MongoCursor::setReadPreference — Set the read preference for this query
read_preferenceThe read preference mode: MongoClient::RP_PRIMARY, MongoClient::RP_PRIMARY_PREFERRED, MongoClient::RP_SECONDARY, MongoClient::RP_SECONDARY_PREFERRED, or MongoClient::RP_NEAREST.
tagsAn array of zero or more tag sets, where each tag set is itself an array of criteria used to match tags on replica set members.
Returns this cursor.
Emits E_WARNING if either parameter is invalid, or if one or more tag sets are provided with the MongoClient::RP_PRIMARY read preference mode.
Exemplo #1 MongoCursor::setReadPreference() tag set array syntaxexample
<?php
$m = new MongoClient();
$cursor = $m->test->users->find();
// Prefer the nearest server in the "east" data center also used for reporting,
// but fall back to a server in the "west" data center
$cursor->setReadPreference(MongoClient::RP_NEAREST, array(
array('dc' => 'east', 'use' => 'reporting'),
array('dc' => 'west'),
));
?>