Memory ManagerCreating a Memory Manager
You can create new a memory manager
(Zend_Memory_Manager object) using the
Zend_Memory::factory($backendName [, $backendOprions])
method.
The first argument $backendName is a string that
names one of the backend implementations supported by Zend_Cache.
The second argument $backendOptions is an optional
backend options array.
'./tmp/' // Directory where to put the swapped memory blocks
);
$memoryManager = Zend_Memory::factory('File', $backendOptions);
]]>Zend_Memory uses Zend_Cache backends as
storage providers.
You may use the special name 'None' as a backend name,
in addition to standard Zend_Cache backends.
If you use 'None' as the backend name, then the memory
manager never swaps memory blocks. This is useful if you know that
memory is not limited or the overall size of objects never reaches
the memory limit.
The 'None' backend doesn't need any option specified.
Managing Memory Objects
This section describes creating and destroying objects in the
managed memory, and settings to control memory manager behavior.
Creating Movable Objects
Create movable objects (objects, which may be swapped) using
the Zend_Memory_Manager::create([$data]) method:
create($data);
]]>
The $data argument is optional and used to
initialize the object value. If the $data
argument is omitted, the value is an empty string.
Creating Locked Objects
Create locked objects (objects, which are not swapped) using
the Zend_Memory_Manager::createLocked([$data]) method:
createLocked($data);
]]>
The $data argument is optional and used to
initialize the object value. If the $data
argument is omitted, the value is an empty string.
Destroying Objects
Memory objects are automatically destroyed and removed from
memory when they go out of scope:
create($data1);
$memObject2 = $memoryManager->create($data2);
$memObject3 = $memoryManager->create($data3);
...
$memList[] = $memObject3;
...
unset($memObject2); // $memObject2 is destroyed here
...
// $memObject1 is destroyed here
// but $memObject3 object is still referenced by $memList
// and is not destroyed
}
]]>
This applies to both movable and locked objects.
Memory Manager SettingsMemory Limit
Memory limit is a number of bytes allowed to be used by loaded
movable objects.
If loading or creation of an object causes memory usage to
exceed of this limit, then the memory manager swaps some other
objects.
You can retrieve or set the memory limit setting using the
getMemoryLimit() and
setMemoryLimit($newLimit) methods:
getMemoryLimit(); // Get memory limit in bytes
$memoryManager->setMemoryLimit($newLimit); // Set memory limit in bytes
]]>
A negative value for memory limit means 'no limit'.
The default value is two-thirds of the value of
'memory_limit' in php.ini or 'no limit' (-1)
if 'memory_limit' is not set in php.ini.
MinSize
MinSize is a minimal size of memory objects, which may be
swapped by memory manager. The memory manager does not swap
objects that are smaller than this value. This reduces the
number of swap/load operations.
You can retrieve or set the minimum size using the
getMinSize() and
setMinSize($newSize) methods:
getMinSize(); // Get MinSize in bytes
$memoryManager->setMinSize($newSize); // Set MinSize limit in bytes
]]>
The default minimum size value is 16KB (16384 bytes).