[转] Azure Redis Best Practices - PHP

PHP

Reuse Connections

The most common problem we have seen with PHP clients is that they either don't support persistent connections or the ability to reuse connections is disabled by default. When you don't reuse connections, it means that you have to pay the cost of establishing a new connection, including the SSL/TLS handshake, each time you want to send a request. This can add a lot of latency to your request time and will manifest itself as a performance problem in your application. Additionally, if you have a high request rate, this can cause significant CPU churn on both the Redis client-side and server-side, which can result in other issues.

As an example, the Predis Redis client has a "persistent" connection property that is false by default. Setting the "persistent" property to true will should improve behavior drastically.

 

Connection Parameters

Predis by default supports various parameters used to control the behaviour of the underlying connection to Redis. These parameters can be specified when creating a new instance of Predis\Client using an URI string or a named array, for example:

$client = new Predis\Client('tcp://127.0.0.1:6379?database=15');

which is equivalent to:

$client = new Predis\Client(array(
    'scheme'   => 'tcp',
    'host'     => '127.0.0.1',
    'port'     => 6379,
    'database' => 15
));

List of connection parameters

• scheme [string - default: tcp]

  Specifies the protocol used to communicate with an instance of Redis. Internally the client uses the connection class associated to the specified connection scheme. By default Predis supports tcp (TCP/IP), unix (UNIX domain sockets) or http (HTTP protocol through Webdis).

• host [string - default: 127.0.0.1]

  IP or hostname of the target server. This is ignored when connecting to Redis using UNIX domain sockets.

• port [integer - default: 6379]

  TCP/IP port of the target server. This is ignored when connecting to Redis using UNIX domain sockets.

• path [string - default: not set]

  Path of the UNIX domain socket file used when connecting to Redis using UNIX domain sockets.

• database [integer - default: not set]

  Accepts a numeric value that is used by Predis to automatically select a logical database with the SELECT command.

• password [string - default: not set]

  Accepts a value used to authenticate with a Redis server protected by password with the AUTH command.

• async [boolean - default: false]

  Specifies if connections to the server is estabilished in a non-blocking way (that is, the client is not blocked while the underlying resource performs the actual connection).

• persistent [boolean - default: false]

  Specifies if the underlying connection resource should be left open when a script ends its lifecycle.

• timeout [float - default: 5.0]

  Timeout (expressed in seconds) used to connect to a Redis server after which an exception is thrown.

• read_write_timeout [float - default: not set]

  Timeout (expressed in seconds) used when performing read or write operations on the underlying network resource after which an exception is thrown. The default value actually depends on the underlying platform but usually it is 60 seconds.

• alias [string - default: not set]

  Identifies a connection by providing a mnemonic alias. This is mostly useful with aggregated connections such as client-side sharding (cluster) or master/slave replication.

• weight [integer - default: not set]

  Specifies a weight used to balance the distribution of keys asymmetrically across multiple servers when using client-side sharding (cluster).

• iterable_multibulk [boolean - default: false]

  When set to true Predis returns multibulk from Redis as iterator instances instead of plain simple PHP arrays.

• throw_errors [boolean - default: true]

  When set to true server errors generated by Redis are translated to PHP exceptions, otherwise they are returned as normal PHP objects.