Merge pull request #4549 from MrPetovan/task/4518-add-memcached-support

[develop] Performance: Add memcached support/Improve database cache (redux)

boot.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * @file_tag_unsave_file boot.php
+ * @file boot.php
  * This file defines some global constants and includes the central App class.
  */
 
@@ -21,6 +21,7 @@ require_once __DIR__ . DIRECTORY_SEPARATOR . 'vendor' . DIRECTORY_SEPARATOR . 'a
 
 use Friendica\App;
 use Friendica\Core\Addon;
+use Friendica\Core\Cache;
 use Friendica\Core\Config;
 use Friendica\Core\L10n;
 use Friendica\Core\PConfig;
@@ -39,7 +40,7 @@ define('FRIENDICA_PLATFORM',     'Friendica');
 define('FRIENDICA_CODENAME',     'Asparagus');
 define('FRIENDICA_VERSION',      '3.6-dev');
 define('DFRN_PROTOCOL_VERSION',  '2.23');
-define('DB_UPDATE_VERSION',      1255);
+define('DB_UPDATE_VERSION',      1256);
 define('NEW_UPDATE_ROUTINE_VERSION', 1170);
 
 /**
@@ -121,18 +122,20 @@ define('LOGGER_ALL',             4);
 
 /**
  * @name Cache
+ * @deprecated since version 3.6
+ * @see Cache
  *
  * Cache levels
  * @{
  */
-define('CACHE_MONTH',            0);
-define('CACHE_WEEK',             1);
-define('CACHE_DAY',              2);
-define('CACHE_HOUR',             3);
-define('CACHE_HALF_HOUR',        4);
-define('CACHE_QUARTER_HOUR',     5);
-define('CACHE_FIVE_MINUTES',     6);
-define('CACHE_MINUTE',           7);
+define('CACHE_MONTH',            Cache::MONTH);
+define('CACHE_WEEK',             Cache::WEEK);
+define('CACHE_DAY',              Cache::DAY);
+define('CACHE_HOUR',             Cache::HOUR);
+define('CACHE_HALF_HOUR',        Cache::HALF_HOUR);
+define('CACHE_QUARTER_HOUR',     Cache::QUARTER_HOUR);
+define('CACHE_FIVE_MINUTES',     Cache::FIVE_MINUTES);
+define('CACHE_MINUTE',           Cache::MINUTE);
 /* @}*/
 
 /**

database.sql

@@ -1,6 +1,6 @@
 -- ------------------------------------------
 -- Friendica 3.6-dev (Asparagus)
--- DB_UPDATE_VERSION 1255
+-- DB_UPDATE_VERSION 1256
 -- ------------------------------------------
 
 
@@ -55,12 +55,12 @@ CREATE TABLE IF NOT EXISTS `auth_codes` (
 -- TABLE cache
 --
 CREATE TABLE IF NOT EXISTS `cache` (
-	`k` varbinary(255) NOT NULL COMMENT '',
-	`v` mediumtext COMMENT '',
-	`expire_mode` tinyint unsigned NOT NULL DEFAULT 0 COMMENT '',
-	`updated` datetime NOT NULL DEFAULT '0001-01-01 00:00:00' COMMENT '',
+	`k` varbinary(255) NOT NULL COMMENT 'cache key',
+	`v` mediumtext COMMENT 'cached serialized value',
+	`expires` datetime NOT NULL DEFAULT '0001-01-01 00:00:00' COMMENT 'datetime of cache expiration',
+	`updated` datetime NOT NULL DEFAULT '0001-01-01 00:00:00' COMMENT 'datetime of cache insertion',
 	 PRIMARY KEY(`k`),
-	 INDEX `expire_mode_updated` (`expire_mode`,`updated`)
+	 INDEX `k_expires` (`k`,`expires`)
 ) DEFAULT COLLATE utf8mb4_general_ci;
 
 --

doc/database/db_cache.md

@@ -1,11 +1,13 @@
 Table cache
 ===========
 
+Stores temporary data
+
 | Field        | Description                        | Type         | Null | Key | Default             | Extra |
 | ------------ | ---------------------------------- | ------------ | ---- | --- | ------------------- | ----- |
-| k            | horizontal width + url or resource | varchar(255) | NO   | PRI | NULL                |       |
-| v            | OEmbed response from site          | text         | NO   |     | NULL                |       |
+| k            | cache key                          | varchar(255) | NO   | PRI | NULL                |       |
+| v            | cached serialized value            | text         | NO   |     | NULL                |       |
+| expires      | datetime of cache expiration       | datetime     | NO   | MUL | 0001-01-01 00:00:00 |       |
 | updated      | datetime of cache insertion        | datetime     | NO   | MUL | 0001-01-01 00:00:00 |       |
-| expire_mode  |                                    | int(11)      | NO   |     | 0                   |       |
 
 Return to [database documentation](help/database)

doc/htconfig.md

@@ -58,9 +58,11 @@ Example: To set the automatic database cleanup process add this line to your .ht
 * **max_processes_backend** - Maximum number of concurrent database processes for background tasks. Default value is 5.
 * **max_processes_frontend** - Maximum number of concurrent database processes for foreground tasks. Default value is 20.
 * **min_poll_interval** - minimal distance in minutes between two polls for a contact. Default is 1. Reasonable values are between 1 and 59.
-* **memcache** (Boolean) - Use memcache. To use memcache the PECL extension "memcache" has to be installed and activated.
-* **memcache_host** - Hostname of the memcache daemon. Default is '127.0.0.1'.
-* **memcache_port** - Portnumber of the memcache daemon. Default is 11211.
+* **session_handler** (database|cache|native) - Whether to use Cache to store session data or to use PHP native session storage. Default value is `database`.
+* **cache_driver** (database|memcache|memcached) - Whether to use Memcache or Memcached to store temporary cache. Default value is `database`.
+* **memcache_host** - Host name of the memcache daemon. Default is '127.0.0.1'.
+* **memcache_port** - Port number of the memcache daemon. Default is 11211.
+* **memcached_hosts** - Array of Memcached servers info `[host, port(, weight)]`. Default value is `[['127.0.0.1', 11211]]`.
 * **no_count** (Boolean) - Don't do count calculations (currently only when showing albums)
 * **no_oembed** (Boolean) - Don't use OEmbed to fetch more information about a link.
 * **no_smilies** (Boolean) - Don't show smilies.

include/api.php

@@ -317,12 +317,16 @@ function api_call(App $a)
 					/// @TODO round() really everywhere?
 					logger(
 						parse_url($a->query_string, PHP_URL_PATH) . ": " . sprintf(
-							"Database: %s/%s, Network: %s, I/O: %s, Other: %s, Total: %s",
+							"Database: %s/%s, Cache %s/%s, Network: %s, I/O: %s, Other: %s, Total: %s",
 							round($a->performance["database"] - $a->performance["database_write"], 3),
 							round($a->performance["database_write"], 3),
+							round($a->performance["cache"], 3),
+							round($a->performance["cache_write"], 3),
 							round($a->performance["network"], 2),
 							round($a->performance["file"], 2),
-							round($duration - ($a->performance["database"] + $a->performance["network"]	+ $a->performance["file"]), 2),
+							round($duration - ($a->performance["database"]
+								+ $a->performance["cache"] + $a->performance["cache_write"]
+								+ $a->performance["network"] + $a->performance["file"]), 2),
 							round($duration, 2)
 						),
 						LOGGER_DEBUG
@@ -344,6 +348,21 @@ function api_call(App $a)
 							}
 						}
 
+						$o = "Cache Read:\n";
+						foreach ($a->callstack["cache"] as $func => $time) {
+							$time = round($time, 3);
+							if ($time > 0) {
+								$o .= $func . ": " . $time . "\n";
+							}
+						}
+						$o .= "\nCache Write:\n";
+						foreach ($a->callstack["cache_write"] as $func => $time) {
+							$time = round($time, 3);
+							if ($time > 0) {
+								$o .= $func . ": " . $time . "\n";
+							}
+						}
+
 						$o .= "\nNetwork:\n";
 						foreach ($a->callstack["network"] as $func => $time) {
 							$time = round($time, 3);

src/App.php

@@ -148,6 +148,8 @@ class App
 		$this->performance['start'] = microtime(true);
 		$this->performance['database'] = 0;
 		$this->performance['database_write'] = 0;
+		$this->performance['cache'] = 0;
+		$this->performance['cache_write'] = 0;
 		$this->performance['network'] = 0;
 		$this->performance['file'] = 0;
 		$this->performance['rendering'] = 0;
@@ -157,6 +159,8 @@ class App
 
 		$this->callstack['database'] = [];
 		$this->callstack['database_write'] = [];
+		$this->callstack['cache'] = [];
+		$this->callstack['cache_write'] = [];
 		$this->callstack['network'] = [];
 		$this->callstack['file'] = [];
 		$this->callstack['rendering'] = [];

src/Core/Cache.php

@@ -4,44 +4,45 @@
  */
 namespace Friendica\Core;
 
+use Friendica\Core\Cache;
 use Friendica\Core\Config;
-use Friendica\Database\DBM;
-use Friendica\Util\DateTimeFormat;
-use dba;
-use Memcache;
-
-require_once 'include/dba.php';
 
 /**
  * @brief Class for storing data for a short time
  */
-class Cache
+class Cache extends \Friendica\BaseObject
 {
+	const MONTH        = 0;
+	const WEEK         = 1;
+	const DAY          = 2;
+	const HOUR         = 3;
+	const HALF_HOUR    = 4;
+	const QUARTER_HOUR = 5;
+	const FIVE_MINUTES = 6;
+	const MINUTE       = 7;
+
 	/**
-	 * @brief Check for Memcache and open a connection if configured
-	 *
-	 * @return Memcache|boolean The Memcache object - or "false" if not successful
+	 * @var Cache\ICacheDriver
 	 */
-	public static function memcache()
+	static $driver = null;
+
+	public static function init()
 	{
-		if (!class_exists('Memcache', false)) {
-			return false;
-		}
-
-		if (!Config::get('system', 'memcache')) {
-			return false;
-		}
-
+		switch(Config::get('system', 'cache_driver', 'database')) {
+			case 'memcache':
 				$memcache_host = Config::get('system', 'memcache_host', '127.0.0.1');
 				$memcache_port = Config::get('system', 'memcache_port', 11211);
 
-		$memcache = new Memcache();
+				self::$driver = new Cache\MemcacheCacheDriver($memcache_host, $memcache_port);
+				break;
+			case 'memcached':
+				$memcached_hosts = Config::get('system', 'memcached_hosts', [['127.0.0.1', 11211]]);
 
-		if (!$memcache->connect($memcache_host, $memcache_port)) {
-			return false;
+				self::$driver = new Cache\MemcachedCacheDriver($memcached_hosts);
+				break;
+			default:
+				self::$driver = new Cache\DatabaseCacheDriver();
 		}
-
-		return $memcache;
 	}
 
 	/**
@@ -51,31 +52,31 @@ class Cache
 	 *
 	 * @return integer The cache duration in seconds
 	 */
-	private static function duration($level)
+	public static function duration($level)
 	{
 		switch ($level) {
-			case CACHE_MONTH:
+			case self::MONTH:
 				$seconds = 2592000;
 				break;
-			case CACHE_WEEK:
+			case self::WEEK:
 				$seconds = 604800;
 				break;
-			case CACHE_DAY:
+			case self::DAY:
 				$seconds = 86400;
 				break;
-			case CACHE_HOUR:
+			case self::HOUR:
 				$seconds = 3600;
 				break;
-			case CACHE_HALF_HOUR:
+			case self::HALF_HOUR:
 				$seconds = 1800;
 				break;
-			case CACHE_QUARTER_HOUR:
+			case self::QUARTER_HOUR:
 				$seconds = 900;
 				break;
-			case CACHE_FIVE_MINUTES:
+			case self::FIVE_MINUTES:
 				$seconds = 300;
 				break;
-			case CACHE_MINUTE:
+			case self::MINUTE:
 			default:
 				$seconds = 60;
 				break;
@@ -83,6 +84,20 @@ class Cache
 		return $seconds;
 	}
 
+	/**
+	 * Returns the current cache driver
+	 *
+	 * @return Cache\ICacheDriver
+	 */
+	private static function getDriver()
+	{
+		if (self::$driver === null) {
+			self::init();
+		}
+
+		return self::$driver;
+	}
+
 	/**
 	 * @brief Fetch cached data according to the key
 	 *
@@ -92,40 +107,13 @@ class Cache
 	 */
 	public static function get($key)
 	{
-		$memcache = self::memcache();
-		if (is_object($memcache)) {
-			// We fetch with the hostname as key to avoid problems with other applications
-			$cached = $memcache->get(get_app()->get_hostname().":".$key);
-			$value = @unserialize($cached);
+		$time = microtime(true);
 
-			// Only return a value if the serialized value is valid.
-			// We also check if the db entry is a serialized
-			// boolean 'false' value (which we want to return).
-			if ($cached === serialize(false) || $value !== false) {
-				return $value;
-			}
+		$return = self::getDriver()->get($key);
 
-			return null;
-		}
+		self::getApp()->save_timestamp($time, 'cache');
 
-		// Frequently clear cache
-		self::clear();
-
-		$cache = dba::selectFirst('cache', ['v'], ['k' => $key]);
-
-		if (DBM::is_result($cache)) {
-			$cached = $cache['v'];
-			$value = @unserialize($cached);
-
-			// Only return a value if the serialized value is valid.
-			// We also check if the db entry is a serialized
-			// boolean 'false' value (which we want to return).
-			if ($cached === serialize(false) || $value !== false) {
-				return $value;
-			}
-		}
-
-		return null;
+		return $return;
 	}
 
 	/**
@@ -137,20 +125,17 @@ class Cache
 	 * @param mixed   $value    The value that is about to be stored
 	 * @param integer $duration The cache lifespan
 	 *
-	 * @return void
+	 * @return bool
 	 */
-	public static function set($key, $value, $duration = CACHE_MONTH)
+	public static function set($key, $value, $duration = self::MONTH)
 	{
-		// Do we have an installed memcache? Use it instead.
-		$memcache = self::memcache();
-		if (is_object($memcache)) {
-			// We store with the hostname as key to avoid problems with other applications
-			$memcache->set(get_app()->get_hostname().":".$key, serialize($value), MEMCACHE_COMPRESSED, self::duration($duration));
-			return;
-		}
-		$fields = ['v' => serialize($value), 'expire_mode' => $duration, 'updated' => DateTimeFormat::utcNow()];
-		$condition = ['k' => $key];
-		dba::update('cache', $fields, $condition, true);
+		$time = microtime(true);
+
+		$return = self::getDriver()->set($key, $value, $duration);
+
+		self::getApp()->save_timestamp($time, 'cache_write');
+
+		return $return;
 	}
 
 	/**
@@ -160,76 +145,8 @@ class Cache
 	 *
 	 * @return void
 	 */
-	public static function clear($max_level = CACHE_MONTH)
+	public static function clear()
 	{
-		// Clear long lasting cache entries only once a day
-		if (Config::get("system", "cache_cleared_day") < time() - self::duration(CACHE_DAY)) {
-			if ($max_level == CACHE_MONTH) {
-				$condition = ["`updated` < ? AND `expire_mode` = ?",
-						DateTimeFormat::utc("now - 30 days"),
-						CACHE_MONTH];
-				dba::delete('cache', $condition);
-			}
-
-			if ($max_level <= CACHE_WEEK) {
-				$condition = ["`updated` < ? AND `expire_mode` = ?",
-						DateTimeFormat::utc("now - 7 days"),
-						CACHE_WEEK];
-				dba::delete('cache', $condition);
-			}
-
-			if ($max_level <= CACHE_DAY) {
-				$condition = ["`updated` < ? AND `expire_mode` = ?",
-						DateTimeFormat::utc("now - 1 days"),
-						CACHE_DAY];
-				dba::delete('cache', $condition);
-			}
-			Config::set("system", "cache_cleared_day", time());
-		}
-
-		if (($max_level <= CACHE_HOUR) && (Config::get("system", "cache_cleared_hour")) < time() - self::duration(CACHE_HOUR)) {
-			$condition = ["`updated` < ? AND `expire_mode` = ?",
-					DateTimeFormat::utc("now - 1 hours"),
-					CACHE_HOUR];
-			dba::delete('cache', $condition);
-
-			Config::set("system", "cache_cleared_hour", time());
-		}
-
-		if (($max_level <= CACHE_HALF_HOUR) && (Config::get("system", "cache_cleared_half_hour")) < time() - self::duration(CACHE_HALF_HOUR)) {
-			$condition = ["`updated` < ? AND `expire_mode` = ?",
-					DateTimeFormat::utc("now - 30 minutes"),
-					CACHE_HALF_HOUR];
-			dba::delete('cache', $condition);
-
-			Config::set("system", "cache_cleared_half_hour", time());
-		}
-
-		if (($max_level <= CACHE_QUARTER_HOUR) && (Config::get("system", "cache_cleared_quarter_hour")) < time() - self::duration(CACHE_QUARTER_HOUR)) {
-			$condition = ["`updated` < ? AND `expire_mode` = ?",
-					DateTimeFormat::utc("now - 15 minutes"),
-					CACHE_QUARTER_HOUR];
-			dba::delete('cache', $condition);
-
-			Config::set("system", "cache_cleared_quarter_hour", time());
-		}
-
-		if (($max_level <= CACHE_FIVE_MINUTES) && (Config::get("system", "cache_cleared_five_minute")) < time() - self::duration(CACHE_FIVE_MINUTES)) {
-			$condition = ["`updated` < ? AND `expire_mode` = ?",
-					DateTimeFormat::utc("now - 5 minutes"),
-					CACHE_FIVE_MINUTES];
-			dba::delete('cache', $condition);
-
-			Config::set("system", "cache_cleared_five_minute", time());
-		}
-
-		if (($max_level <= CACHE_MINUTE) && (Config::get("system", "cache_cleared_minute")) < time() - self::duration(CACHE_MINUTE)) {
-			$condition = ["`updated` < ? AND `expire_mode` = ?",
-					DateTimeFormat::utc("now - 1 minutes"),
-					CACHE_MINUTE];
-			dba::delete('cache', $condition);
-
-			Config::set("system", "cache_cleared_minute", time());
-		}
+		return self::getDriver()->clear();
 	}
 }

src/Core/Cache/DatabaseCacheDriver.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace Friendica\Core\Cache;
+
+use dba;
+use Friendica\Core\Cache;
+use Friendica\Database\DBM;
+use Friendica\Util\DateTimeFormat;
+
+/**
+ * Database Cache Driver
+ *
+ * @author Hypolite Petovan <mrpetovan@gmail.com>
+ */
+class DatabaseCacheDriver implements ICacheDriver
+{
+	public function get($key)
+	{
+		$cache = dba::selectFirst('cache', ['v'], ['`k` = ? AND `expires` >= ?', $key, DateTimeFormat::utcNow()]);
+
+		if (DBM::is_result($cache)) {
+			$cached = $cache['v'];
+			$value = @unserialize($cached);
+
+			// Only return a value if the serialized value is valid.
+			// We also check if the db entry is a serialized
+			// boolean 'false' value (which we want to return).
+			if ($cached === serialize(false) || $value !== false) {
+				return $value;
+			}
+		}
+
+		return null;
+	}
+
+	public function set($key, $value, $duration = Cache::MONTH)
+	{
+		$fields = [
+			'v'       => serialize($value),
+			'expires' => DateTimeFormat::utc('now + ' . Cache::duration($duration) . ' seconds'),
+			'updated' => DateTimeFormat::utcNow()
+		];
+
+		return dba::update('cache', $fields, ['k' => $key], true);
+	}
+
+	public function delete($key)
+	{
+		return dba::delete('cache', ['k' => $key]);
+	}
+
+	public function clear()
+	{
+		return dba::delete('cache', ['`expires` < NOW()']);
+	}
+}

src/Core/Cache/ICacheDriver.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace Friendica\Core\Cache;
+
+use Friendica\Core\Cache;
+
+/**
+ * Cache Driver Interface
+ *
+ * @author Hypolite Petovan <mrpetovan@gmail.com>
+ */
+interface ICacheDriver
+{
+	/**
+	 * Fetches cached data according to the key
+	 *
+	 * @param string $key The key to the cached data
+	 *
+	 * @return mixed Cached $value or "null" if not found
+	 */
+	public function get($key);
+
+	/**
+	 * Stores data in the cache identified by the key. The input $value can have multiple formats.
+	 *
+	 * @param string  $key      The cache key
+	 * @param mixed   $value    The value to store
+	 * @param integer $duration The cache lifespan, must be one of the Cache constants
+	 *
+	 * @return bool
+	 */
+	public function set($key, $value, $duration = Cache::MONTH);
+
+
+	/**
+	 * Delete a key from the cache
+	 *
+	 * @param string $key
+	 *
+	 * @return bool
+	 */
+	public function delete($key);
+
+	/**
+	 * Remove outdated data from the cache
+	 *
+	 * @return bool
+	 */
+	public function clear();
+}

src/Core/Cache/MemcacheCacheDriver.php

@@ -0,0 +1,77 @@
+<?php
+
+namespace Friendica\Core\Cache;
+
+use Friendica\BaseObject;
+use Friendica\Core\Cache;
+
+/**
+ * Memcache Cache Driver
+ *
+ * @author Hypolite Petovan <mrpetovan@gmail.com>
+ */
+class MemcacheCacheDriver extends BaseObject implements ICacheDriver
+{
+	/**
+	 * @var Memcache
+	 */
+	private $memcache;
+
+	public function __construct($memcache_host, $memcache_port)
+	{
+		if (!class_exists('Memcache', false)) {
+			throw new \Exception('Memcache class isn\'t available');
+		}
+
+		$this->memcache = new \Memcache();
+
+		if (!$this->memcache->connect($memcache_host, $memcache_port)) {
+			throw new \Exception('Expected Memcache server at ' . $memcache_host . ':' . $memcache_port . ' isn\'t available');
+		}
+	}
+
+	public function get($key)
+	{
+		$return = null;
+
+		// We fetch with the hostname as key to avoid problems with other applications
+		$cached = $this->memcache->get(self::getApp()->get_hostname() . ':' . $key);
+
+		// @see http://php.net/manual/en/memcache.get.php#84275
+		if (is_bool($cached) || is_double($cached) || is_long($cached)) {
+			return $return;
+		}
+
+		$value = @unserialize($cached);
+
+		// Only return a value if the serialized value is valid.
+		// We also check if the db entry is a serialized
+		// boolean 'false' value (which we want to return).
+		if ($cached === serialize(false) || $value !== false) {
+			$return = $value;
+		}
+
+		return $return;
+	}
+
+	public function set($key, $value, $duration = Cache::MONTH)
+	{
+		// We store with the hostname as key to avoid problems with other applications
+		return $this->memcache->set(
+			self::getApp()->get_hostname() . ":" . $key,
+			serialize($value),
+			MEMCACHE_COMPRESSED,
+			Cache::duration($duration)
+		);
+	}
+
+	public function delete($key)
+	{
+		return $this->memcache->delete($key);
+	}
+
+	public function clear()
+	{
+		return true;
+	}
+}

src/Core/Cache/MemcachedCacheDriver.php

@@ -0,0 +1,68 @@
+<?php
+
+namespace Friendica\Core\Cache;
+
+use Friendica\BaseObject;
+use Friendica\Core\Cache;
+
+/**
+ * Memcached Cache Driver
+ *
+ * @author Hypolite Petovan <mrpetovan@gmail.com>
+ */
+class MemcachedCacheDriver extends BaseObject implements ICacheDriver
+{
+	/**
+	 * @var Memcached
+	 */
+	private $memcached;
+
+	public function __construct(array $memcached_hosts)
+	{
+		if (!class_exists('Memcached', false)) {
+			throw new \Exception('Memcached class isn\'t available');
+		}
+
+		$this->memcached = new \Memcached();
+
+		$this->memcached->addServers($memcached_hosts);
+
+		if (count($this->memcached->getServerList()) == 0) {
+			throw new \Exception('Expected Memcached servers aren\'t available, config:' . var_export($memcached_hosts, true));
+		}
+	}
+
+	public function get($key)
+	{
+		$return = null;
+
+		// We fetch with the hostname as key to avoid problems with other applications
+		$value = $this->memcached->get(self::getApp()->get_hostname() . ':' . $key);
+
+		if ($this->memcached->getResultCode() === \Memcached::RES_SUCCESS) {
+			$return = $value;
+		}
+
+		return $return;
+	}
+
+	public function set($key, $value, $duration = Cache::MONTH)
+	{
+		// We store with the hostname as key to avoid problems with other applications
+		return $this->memcached->set(
+			self::getApp()->get_hostname() . ":" . $key,
+			$value,
+			Cache::duration($duration)
+		);
+	}
+
+	public function delete($key)
+	{
+		return $this->memcached->delete($key);
+	}
+
+	public function clear()
+	{
+		return true;
+	}
+}

src/Core/Session.php

@@ -5,8 +5,8 @@
  */
 namespace Friendica\Core;
 
+use Friendica\Core\Session\CacheSessionHandler;
 use Friendica\Core\Session\DatabaseSessionHandler;
-use Friendica\Core\Session\MemcacheSessionHandler;
 
 /**
  * High-level Session service class
@@ -28,10 +28,10 @@ class Session
 			ini_set('session.cookie_secure', 1);
 		}
 
-		if (!Config::get('system', 'disable_database_session')) {
-			$memcache = Cache::memcache();
-			if (is_object($memcache)) {
-				$SessionHandler = new MemcacheSessionHandler($memcache);
+		$session_handler = Config::get('system', 'session_handler', 'database');
+		if ($session_handler != 'native') {
+			if ($session_handler == 'cache' && Config::get('system', 'cache_driver', 'database') != 'database') {
+				$SessionHandler = new CacheSessionHandler();
 			} else {
 				$SessionHandler = new DatabaseSessionHandler();
 			}

src/Core/Session/CacheSessionHandler.php

@@ -3,34 +3,20 @@
 namespace Friendica\Core\Session;
 
 use Friendica\BaseObject;
+use Friendica\Core\Cache;
 use Friendica\Core\Session;
 use SessionHandlerInterface;
-use Memcache;
 
 require_once 'boot.php';
 require_once 'include/text.php';
 
 /**
- * SessionHandler using Memcache
+ * SessionHandler using Friendica Cache
  *
  * @author Hypolite Petovan <mrpetovan@gmail.com>
  */
-class MemcacheSessionHandler extends BaseObject implements SessionHandlerInterface
+class CacheSessionHandler extends BaseObject implements SessionHandlerInterface
 {
-	/**
-	 * @var Memcache
-	 */
-	private $memcache = null;
-
-	/**
-	 *
-	 * @param Memcache $memcache
-	 */
-	public function __construct(Memcache $memcache)
-	{
-		$this->memcache = $memcache;
-	}
-
 	public function open($save_path, $session_name)
 	{
 		return true;
@@ -42,8 +28,8 @@ class MemcacheSessionHandler extends BaseObject implements SessionHandlerInterfa
 			return '';
 		}
 
-		$data = $this->memcache->get(self::getApp()->get_hostname() . ":session:" . $session_id);
-		if (!is_bool($data)) {
+		$data = Cache::get('session:' . $session_id);
+		if (!empty($data)) {
 			Session::$exists = true;
 			return $data;
 		}
@@ -72,14 +58,7 @@ class MemcacheSessionHandler extends BaseObject implements SessionHandlerInterfa
 			return true;
 		}
 
-		$expire = time() + Session::$expire;
-
-		$this->memcache->set(
-			self::getApp()->get_hostname() . ":session:" . $session_id,
-			$session_data,
-			MEMCACHE_COMPRESSED,
-			$expire
-		);
+		Cache::set('session:' . $session_id, $session_data, Session::$expire);
 
 		return true;
 	}
@@ -91,7 +70,7 @@ class MemcacheSessionHandler extends BaseObject implements SessionHandlerInterfa
 
 	public function destroy($id)
 	{
-		$this->memcache->delete(self::getApp()->get_hostname() . ":session:" . $id);
+		Cache::delete('session:' . $id);
 		return true;
 	}
 

src/Core/Worker.php

@@ -325,6 +325,8 @@ class Worker
 			$a->performance["start"] = microtime(true);
 			$a->performance["database"] = 0;
 			$a->performance["database_write"] = 0;
+			$a->performance["cache"] = 0;
+			$a->performance["cache_write"] = 0;
 			$a->performance["network"] = 0;
 			$a->performance["file"] = 0;
 			$a->performance["rendering"] = 0;
@@ -409,6 +411,24 @@ class Worker
 						}
 					}
 				}
+				if (isset($a->callstack["dache"])) {
+					$o .= "\nCache Read:\n";
+					foreach ($a->callstack["dache"] as $func => $time) {
+						$time = round($time, 3);
+						if ($time > 0) {
+							$o .= $func.": ".$time."\n";
+						}
+					}
+				}
+				if (isset($a->callstack["dache_write"])) {
+					$o .= "\nCache Write:\n";
+					foreach ($a->callstack["dache_write"] as $func => $time) {
+						$time = round($time, 3);
+						if ($time > 0) {
+							$o .= $func.": ".$time."\n";
+						}
+					}
+				}
 				if (isset($a->callstack["network"])) {
 					$o .= "\nNetwork:\n";
 					foreach ($a->callstack["network"] as $func => $time) {
@@ -422,12 +442,16 @@ class Worker
 
 			logger(
 				"ID ".$queue["id"].": ".$funcname.": ".sprintf(
-					"DB: %s/%s, Net: %s, I/O: %s, Other: %s, Total: %s".$o,
+					"DB: %s/%s, Cache: %s/%s, Net: %s, I/O: %s, Other: %s, Total: %s".$o,
 					number_format($a->performance["database"] - $a->performance["database_write"], 2),
 					number_format($a->performance["database_write"], 2),
+					number_format($a->performance["cache"], 2),
+					number_format($a->performance["cache_write"], 2),
 					number_format($a->performance["network"], 2),
 					number_format($a->performance["file"], 2),
-					number_format($duration - ($a->performance["database"] + $a->performance["network"] + $a->performance["file"]), 2),
+					number_format($duration - ($a->performance["database"]
+						+ $a->performance["cache"] + $a->performance["cache_write"]
+						+ $a->performance["network"] + $a->performance["file"]), 2),
 					number_format($duration, 2)
 				),
 				LOGGER_DEBUG

src/Database/DBStructure.php

@@ -712,16 +712,16 @@ class DBStructure
 						]
 				];
 		$database["cache"] = [
-				"comment" => "Used to store different data that doesn't to be stored for a long time",
+				"comment" => "Stores temporary data",
 				"fields" => [
-						"k" => ["type" => "varbinary(255)", "not null" => "1", "primary" => "1", "comment" => ""],
-						"v" => ["type" => "mediumtext", "comment" => ""],
-						"expire_mode" => ["type" => "tinyint unsigned", "not null" => "1", "default" => "0", "comment" => ""],
-						"updated" => ["type" => "datetime", "not null" => "1", "default" => NULL_DATE, "comment" => ""],
+						"k" => ["type" => "varbinary(255)", "not null" => "1", "primary" => "1", "comment" => "cache key"],
+						"v" => ["type" => "mediumtext", "comment" => "cached serialized value"],
+						"expires" => ["type" => "datetime", "not null" => "1", "default" => NULL_DATE, "comment" => "datetime of cache expiration"],
+						"updated" => ["type" => "datetime", "not null" => "1", "default" => NULL_DATE, "comment" => "datetime of cache insertion"],
 						],
 				"indexes" => [
 						"PRIMARY" => ["k"],
-						"expire_mode_updated" => ["expire_mode", "updated"],
+						"k_expires" => ["k", "expires"],
 						]
 				];
 		$database["challenge"] = [