Issue #2696129 by Jeremy: Add support for igbinary serialize/unserialize

README.txt

@@ -298,6 +298,41 @@ except for the 'cache_page' bin which will use the 'something_else_unique'
 prefix. Not that if using a keyed array for specifying prefix, you must specify
 the 'default' prefix.
 
+## EXPERIMENTAL - ALTERNATIVE SERIALIZE: IGBINARY ##
+
+This is a new experimental feature added to the memcache module in version
+7.x-1.6 and should be tested carefully before utilizing in production.
+
+To optimize how data is serialized before it is written to memcache, you can
+enable the igbinary PHP extension which converts from using PHP's human
+readable serialized data structures to a compact binary format. The igbinary
+documentation claims on average a 50% reducation in storage requirements,
+reducing the amount of traffic sent over the network. It goes on to explain:
+
+  "Unserialization performance is at least on par with the standard PHP
+   serializer.  Serialization performance depends on the 'compact_strings'
+   option which enables duplicate string tracking. String are inserted to a
+   hash table which adds some overhead. In usual scenarios this does not have
+   much significance since usage pattern is 'serialize rarely, unserialize
+   often'. With 'compact_strings' option igbinary is usually a bit slower
+   than the standard serializer. Without it, a bit faster."
+
+If the igbinary extension is enabled, the memcache modue will use it by
+default. You can verify which serialize function is being used by enabling the
+memcache_admin module and visiting admin/reports/memcache. To disable igbinary
+when the php extension is installed add the following to your settings.php and
+then restart all memcached daemons:
+
+$conf['memcache_enable_igbinary'] = FALSE;
+
+The project is maintained on GitHub:
+ - https://github.com/phadej/igbinary
+
+The official PECL package can be found at:
+ - https://pecl.php.net/package/igbinary
+
+Version 2.0.1 or greater is recommended.
+
 ## MAXIMUM LENGTHS ##
 
 If the length of your prefix + key + bin combine to be more than 250 characters,

dmemcache.inc

@@ -149,7 +149,12 @@ function _dmemcache_set_pieces($key, $value, $exp = 0, $bin = 'cache', $mc = NUL
     $serialized = FALSE;
   }
   else {
-    $data = serialize($value);
+    if (extension_loaded('igbinary') && variable_get('memcache_enable_igbinary', TRUE)) {
+      $data = igbinary_serialize($value);
+    }
+    else {
+      $data = serialize($value);
+    }
     $serialized = TRUE;
   }
 
@@ -326,7 +331,17 @@ function _dmemcache_get_pieces($item, $key, $bin = 'cache', $mc = NULL) {
   unset($pieces);
 
   // If necessary unserialize the item.
-  return empty($item->serialized) ? $data : unserialize($data);
+  if (empty($item->serialized)) {
+    return $data;
+  }
+  else {
+    if (extension_loaded('igbinary') && variable_get('memcache_enable_igbinary', TRUE)) {
+      return igbinary_unserialize($data);
+    }
+    else {
+      return unserialize($data);
+    }
+  }
 }
 
 /**

memcache_admin/memcache_admin.module

@@ -334,6 +334,25 @@ function memcache_admin_stats($bin = 'default') {
     }
     $report['uptime'][] = $item;
 
+    // Report which serialize function is being used.
+    $item = array(
+      'label' => t('Serialize function')
+    );
+    if (extension_loaded('igbinary') && variable_get('memcache_enable_igbinary', TRUE)) {
+      $serialize_function = t('igbinary_serialize v!version', array('!version' => phpversion('igbinary')));
+    }
+    else {
+      $serialize_function = 'serialize';
+    }
+    if (count($aggregate)) {
+      $report['uptime'][] = $item;
+      $item['servers'] = $serialize_function;
+    }
+    else {
+      $item['servers'] = array($servers[0] => $serialize_function);
+    }
+    $report['uptime'][] = $item;
+
     // Report server time.
     $item = array(
       'label' => t('Time'),