<?php
$mode = MongoDB\Driver\ReadPreference::RP_SECONDARY_PREFERRED);
/* Null and an empty array both denote no tag set preference. */
$rp = new MongoDB\Driver\ReadPreference($mode, null);
var_dump($rp->getTagSets());
$rp = new MongoDB\Driver\ReadPreference($mode, []);
var_dump($rp->getTagSets());
/* Prefer a node in New York, but fall back to any available node. */
$rp = new MongoDB\Driver\ReadPreference($mode, [['dc' => 'ny']]);
var_dump($rp->getTagSets());
/* Prefer a node in the New York, followed by a node in San Francisco that is
labeled for reporting usage, and finally fall back to any available node. */
$rp = new MongoDB\Driver\ReadPreference($mode, [
['dc' => 'ny'],
['dc' => 'sf', 'use' => 'reporting'],
[],
]);
var_dump($rp->getTagSets());
?>
The above example will output:
array(0) {
}
array(0) {
}
array(2) {
[0]=>
array(1) {
["dc"]=>
string(2) "ny"
}
[1]=>
array(0) {
}
}
array(3) {
[0]=>
array(1) {
["dc"]=>
string(2) "ny"
}
[1]=>
array(2) {
["dc"]=>
string(2) "sf"
["use"]=>
string(9) "reporting"
}
[2]=>
array(0) {
}
}