MongoCommandCursor::setReadPreference
(PECL mongo >=1.6.0)
MongoCommandCursor::setReadPreference — Set the read preference for this command
설명
public MongoCommandCursor MongoCommandCursor::setReadPreference
( string
$read_preference
[, array $tags
] )인수
-
read_preference -
The read preference mode:
MongoClient::RP_PRIMARY,MongoClient::RP_PRIMARY_PREFERRED,MongoClient::RP_SECONDARY,MongoClient::RP_SECONDARY_PREFERRED, orMongoClient::RP_NEAREST. -
tags -
An 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.
반환값
Returns this cursor.
오류/예외
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.
예제
Example #1 MongoCommandCursor::setReadPreference() tag set array syntax example
<?php
$m = new MongoClient('mongodb://rs1.example.com:27017', array('replicaSet' => 'myReplSetName'));
$collection = $m->selectCollection('test', 'people');
$cursor = $collection->aggregateCursor( [
[ '$group' => [ '_id' => '$name', 'points' => [ '$sum' => '$points' ] ] ],
[ '$sort' => [ 'points' => -1 ] ],
] );
// Prefer the nearest server in the "east" data center also used for reporting,
// but fall back to a server in the "west" data center
$cursor->setReadPreference(MongoClient::RP_NEAREST, [
[ 'dc' => 'east', 'use' => 'reporting' ],
[ 'dc' => 'west' ],
] );
foreach ($cursor as $person) {
// ...
}
// If the read preference is changed, it will be used the next time the cursor
// is rewound and the command is re-executed.
$cursor->setReadPreference(MongoClient::RP_PRIMARY);
foreach ($cursor as $person) {
// ...
}
?>
참고
- The read preferences documentation.
- MongoCommandCursor::getReadPreference() - Get the read preference for this command
- MongoCursorInterface::setReadPreference() - Set the read preference for this query
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