Php/docs/mongocursor.setreadpreference
MongoCursor::setReadPreference
(PECL mongo >=1.3.3)
MongoCursor::setReadPreference — Set the read preference for this query
说明
public MongoCursor::setReadPreference
( string $read_preference
[, array $tags
] ) : MongoCursor
参数
read_preference
- The read preference mode:
MongoClient::RP_PRIMARY
,MongoClient::RP_PRIMARY_PREFERRED
,MongoClient::RP_SECONDARY
,MongoClient::RP_SECONDARY_PREFERRED
, orMongoClient::RP_NEAREST
. tags
- An array of zero or more tag sets, where each tag set is itself an array of criteria used to match tags on replica set members.
返回值
Returns this cursor.
错误/异常
Emits E_WARNING
if either parameter is invalid, or if one or more tag sets are provided with the MongoClient::RP_PRIMARY
read preference mode.
范例
Example #1 MongoCursor::setReadPreference() tag set array syntax example
<?php$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'),));?>
参见
- The read preferences documentation.
- MongoCursor::getReadPreference() - Get the read preference for this query
- MongoCursorInterface::setReadPreference() - Set the read preference for this query