This (extend) backend is an hybrid one. It stores cache records in two other backends : a fast one (but limited) like Apc, Memcache... and a "slow" one like File, Sqlite...
This backend will use the priority parameter (given at the frontend level when storing a record) and the remaining space in the fast backend to optimize the usage of these two backends.
Specify this backend using a word separator -- '-', '.', ' ', or '_'
-- between the words 'Two' and 'Levels' when using the
Zend_Cache::factory() method:
<?php
$cache = Zend_Cache::factory('Core', 'Two Levels');
Available options are :
Table 30. TwoLevels Backend Options
| Option | Data Type | Default Value | Description |
|---|---|---|---|
| slow_backend | String | File | the "slow" backend name |
| fast_backend | String | Apc | the "fast" backend name |
| slow_backend_options | Array | array() |
the "slow" backend options |
| fast_backend_options | Array | array() |
the "fast" backend options |
| slow_backend_custom_naming | Boolean | FALSE |
if TRUE, the slow_backend argument is used as a
complete class name; if FALSE,
the frontend argument is used as the end of
"Zend_Cache_Backend_[...]" class name
|
| fast_backend_custom_naming | Boolean | FALSE |
if TRUE, the fast_backend argument is used as a
complete class name; if FALSE,
the frontend argument is used as the end of
"Zend_Cache_Backend_[...]" class name
|
| slow_backend_autoload | Boolean | FALSE |
if TRUE, there will no require_once for the
slow backend (useful only for custom backends)
|
| fast_backend_autoload | Boolean | FALSE |
if TRUE, there will no require_once for the fast
backend (useful only for custom backends)
|
| auto_refresh_fast_cache | Boolean | TRUE |
if TRUE, auto refresh the fast cache when a
cache record is hit
|
| stats_update_factor | Integer | 10 | disable / tune the computation of the fast backend filling percentage (when saving a record into cache, computation of the fast backend filling percentage randomly 1 times on x cache writes) |