略微加速

PHP官方手册 - 互联网笔记

PHP - Manual: MongoCommandCursor::setReadPreference

2024-11-13

MongoCommandCursor::setReadPreference

(PECL mongo >=1.6.0)

MongoCommandCursor::setReadPreferenceSet the read preference for this command

说明

public MongoCommandCursor::setReadPreference ( string $read_preference [, array $tags ] ) : MongoCommandCursor

参数

read_preference

The read preference mode: MongoClient::RP_PRIMARY, MongoClient::RP_PRIMARY_PREFERRED, MongoClient::RP_SECONDARY, MongoClient::RP_SECONDARY_PREFERRED, or MongoClient::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.

返回值

Returns this cursor.

错误/异常

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.

范例

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' => -] ],
] );

// 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) {
    
// ...
}

?>

参见

add a note add a note

User Contributed Notes

There are no user contributed notes for this page.

官方地址:https://www.php.net/manual/en/mongocommandcursor.setreadpreference.php

北京半月雨文化科技有限公司.版权所有 京ICP备12026184号-3