MongoCursor::slaveOkay

Sets whether this query can be done on a secondary

&reftitle.description; public `MongoCursor` `MongoCursor::slaveOkay` `bool` `okay` true

Calling this will make the driver route reads to secondaries if:

- You are using a replica set and

- You created a `MongoClient` instance using the option `"replicaSet" => "setName" and`

- There is a healthy secondary that can be reached by the driver.

You can check which server was used for this query by calling `MongoCursor::info` after running the query. It's `server` field will show which server the query was sent to.

Note that you should use this function even if you do not use the automatic routing to secondaries. If you connect directly to a secondary in a replica set, you still need to call this function, which basically tells the database that you are aware that you might be getting older data and you're okay with that. If you do not call this, you'll get "not master" errors when you try to query.

This method will override the static class variable `MongoCursor::$slaveOkay`. It will also override `Mongo::setSlaveOkay`, `MongoDB::setSlaveOkay` and `MongoCollection::setSlaveOkay`.

&reftitle.parameters;

`okay`

- If it is okay to query the secondary.

&reftitle.returnvalues;

Returns this cursor.

&reftitle.errors;

Throws `MongoCursorException` if this cursor has started iterating.

&reftitle.examples;

### `MongoCursor::slaveOkay` example

    <?php

    MongoCursor::$slaveOkay = false;

    // cannot query secondary
    $cursor = $collection->find();

    // can query secondary
    $cursor = $collection->find()->slaveOkay();

    MongoCursor::$slaveOkay = true;

    // can query secondary
    $cursor = $collection->find();

    // cannot query secondary
    $cursor = $collection->find()->slaveOkay(false);

    ?>

&reftitle.seealso;

- mongo.readpreferences
- `MongoCursor::setReadPreference`
- `MongoCursor::getReadPreference`