XenForo-Redis-cache

XenForo + Redis + Glue code

This "addon" is the required gluecode to use Cm_Cache_Backend_Redis to provide a Zend Cache target for Redis.

Additionally, this addon implement caching of thread counts in a forum.

To prevent double encoding of cached data, it is strongly recommended to have the following configuration in XenForo's config.php:

$config['cache']['frontendOptions']['automatic_serialization'] = false;

Warning You must manually flush the cache after changing this setting!

Optionally, (pipelining or loading from a slave can be enabled in XenForo_Model_DataRegistry::getMulti by adding the following lines to config.php. Preferably after setting up the cache.

require(XenForo_Application::getInstance()->getConfigDir().'/SV/RedisCache/Installer.php');

For best performance use: phpredis PECL extension

Sample Redis configuration for XenForo:

$config['cache']['enabled'] = true;
$config['cache']['frontend'] = 'Core';
$config['cache']['frontendOptions']['cache_id_prefix'] = 'xf_';
$config['cache']['backend'] = 'Redis';
$config['cache']['backendOptions'] = array(
        'server' => '127.0.0.1',
        'port' => 6379,
        'connect_retries' => 2,
        'use_lua' => true,
        'compress_data' => 2,
        'read_timeout' => 1,
        'timeout' => 1,
    );

Loading Data from a single slave is possible, or alternatively Redis Sentinel support can be used high-availability. See http://redis.io/topics/sentinel for more information.

Single Slave:

$config['cache']['backendOptions']['load_from_slave'] = array(
        'server' => '127.0.0.1',
        'port' => 6378,
        'connect_retries' => 2,
        'use_lua' => true,
        'compress_data' => 2,
        'read_timeout' => 1,
        'timeout' => 1,
        'retry_reads_on_master' => true,
    );

If 'retry_reads_on_master' is truthy then reads will be retried against master when slave returns "(nil)" value (ie slave is not yet initialized).

Redis Sentinel:

$config['cache']['backendOptions']['sentinel_master'] = 'mymaster';
$config['cache']['backendOptions']['server'] = '127.0.0.1:26379';

'server' now points to a comma delimited list of sentinal servers to find the master. Note; the port must be explicitly listed

To load data from slaves use;

$config['cache']['backendOptions']['load_from_slaves'] = true;

This will prefer any slave with an IP matching an IP on the machine. This is fetched via the non-portable method:shell_exec("hostname --all-ip-addresses") To run on windows, or if shell_exec is disabled, you must define an 'slave-select' attribute.

By default, a local slave is preferred, this can be changed by setting:

$config['cache']['backendOptions']['slave_select_callable'] = function (array $slaves) { 
        $slaveKey = array_rand($slaves, 1);
        return $slaves[$slaveKey];
};

Setting to false (or some non-callable) will fall back to a random slave.

Zend Cache Tags Support

By default the Zend Cache "tags" support is disabled as XenForo does not use it and it introduces additional operations to support it. To enable;

$config['cache']['backendOptions']['enable_tags'] = true;

Licensing:

New BSD License:

• Cm_Cache_Backend_Redis
• Credis

MIT Licensed:

• XenForo Addon code