====== Memcached Setup ======

===== Description =====
This section describes connecting to an already configured Memcache server with either the [[v6:caching:memcached]] or [[v6:caching:memcache]] connection plugins. Information about installation and configuration of Memcached servers can be found [[https://memcached.org/|here]].

===== The Memcache Library =====
There are 2 distinct PEAR modules for connecting to a [[wp>Memcached]] server: the [[https://pecl.php.net/package/memcache|Memcache]] library and the [[https://pecl.php.net/package/memcached|Memcached]] library.
<WRAP tip>
  * Windows support is only available for the //Memcache// library.
  * //Memcache// should be used in PHP 5.x environments on UNIX platforms.
  * //Memcached// should be used in PHP 7.x environments on UNIX platforms.
  * If both libraries are available, //Memcache// will be used.
</WRAP>
===== Why can't I use the memcached library under Windows? =====
The memcached library is much more heavily featured, more modern and better maintained. The problem with it is not a problem with ADOdb, nor a problem with PHP. The PHP module is dependent on the 3rd party library **libmemcache**, which has no Windows support. Any Windows DLLs you might find floating around the web will __always__ be built on the memcache library.


===== Usage =====
<code php>

/*
* Example for logging
*/
$debugStreamHandler    = new StreamHandler('/logs/debug.log', Logger::DEBUG);
$criticalStreamHandler = new StreamHandler('/logs/critical.log', Logger::CRITICAL);

$streamHandlers = array(
    Logger::DEBUG=>$debugStreamHandler,
    Logger::CRITICAL=>$criticalStreamHandler);


$dbParameters = array(
  'host'=>'192.168.86.85',
  'user'=>'adodb',
  'password'=>'adodb',
  'database'=>'employees');


/*
 * Enable memcache
 */

$memcacheClass = new \ADOdb\cache\plugins\memcached\ADOCachingDefinitions;


$memcacheClass->memCacheControllers = array(
    array('host'=>'192.168.86.91','port'=>'11211','weight'=>70),
    array('host'=>'192.168.86.92','port'=>'11211','weight'=>30));
    
$memcacheClass->memCacheOptions = array(
    Memcached::OPT_HASH=>Memcached::HASH_MURMUR
    );


$acd = new ADOdb\ADOConnectionDefinitions(
    $streamHandlers,
    null,
    $memcacheClass);

$acd->driver = 'mysqli';
$acd->dbParameters = $dbParameters;


$obj = new ADOdb\connector($acd);

$db = $obj->connect();


/*
 * look for a cached query with a life of 2400 seconds, in the mygroup group
 */
$options = array('cache'=>array(
       'cachesecs'=>2400,
       'serverkey'=>'mygroup');
       
$sql = 'SELECT code,description FROM xref_table';
$db->execute($sql,null,$options);

</code>
===== Using Debug Mode  =====

The size of query results that can be cached by the memcached server is limited by server configuration. The default is quite small. If the query is too large, and [[v6:userguide:debug|debugging]] is enabled, then an error is displayed.

<code>

ADOdb.DEBUG: MEMCACHED: Loaded the MemCached Libary [] []
ADOdb.DEBUG: MEMCACHED: Successfully set memcache option 2 to 8 [] []
ADOdb.DEBUG: MEMCACHED: 71a071eb865c1bafbcc49e274a7ac6b6 cache failure: Timeout 1 (this is a notice and not an error [] []
ADOdb.DEBUG: MEMCACHED: Successfully wrote query contents on key 71a071eb865c1bafbcc49e274a7ac6b6 to memcache server [] []
ADOdb.DEBUG: MEMCACHED: Item with key 71a071eb865c1bafbcc49e274a7ac6b6 retrieved from the memcache server. [using server key server-test] [] []
</code>

ADOdb currently has no mechanism for splitting large queries into smaller chunks.


{{tag>memcached cache}}