diff --git a/boot.php b/boot.php
index 7fb4591411..7451891fef 100644
--- a/boot.php
+++ b/boot.php
@@ -19,7 +19,7 @@ define ( 'FRIENDICA_PLATFORM',     'Friendica');
 define ( 'FRIENDICA_CODENAME',     'Lily of the valley');
 define ( 'FRIENDICA_VERSION',      '3.4.1' );
 define ( 'DFRN_PROTOCOL_VERSION',  '2.23'    );
-define ( 'DB_UPDATE_VERSION',      1187      );
+define ( 'DB_UPDATE_VERSION',      1188      );
 define ( 'EOL',                    "<br />\r\n"     );
 define ( 'ATOM_TIME',              'Y-m-d\TH:i:s\Z' );
 
@@ -84,6 +84,15 @@ define ( 'LOGGER_DEBUG',           2 );
 define ( 'LOGGER_DATA',            3 );
 define ( 'LOGGER_ALL',             4 );
 
+/**
+ * cache levels
+ */
+
+define ( 'CACHE_MONTH',            0 );
+define ( 'CACHE_WEEK',             1 );
+define ( 'CACHE_DAY',              2 );
+define ( 'CACHE_HOUR',             3 );
+
 /**
  * registration policies
  */
diff --git a/include/Scrape.php b/include/Scrape.php
index 83c099769d..a2bf5ee0aa 100644
--- a/include/Scrape.php
+++ b/include/Scrape.php
@@ -819,7 +819,7 @@ function probe_url($url, $mode = PROBE_NORMAL, $level = 1) {
 		}
 	}
 
-	Cache::set("probe_url:".$mode.":".$url,serialize($result));
+	Cache::set("probe_url:".$mode.":".$url,serialize($result), CACHE_DAY);
 
 	return $result;
 }
diff --git a/include/cache.php b/include/cache.php
index 3a18fe2a5a..d0b0dfafda 100644
--- a/include/cache.php
+++ b/include/cache.php
@@ -5,33 +5,25 @@
 
 	class Cache {
 		public static function get($key) {
-			/*if (function_exists("apc_fetch") AND function_exists("apc_exists"))
-				if (apc_exists($key))
-					return(apc_fetch($key));*/
 
 			$r = q("SELECT `v` FROM `cache` WHERE `k`='%s' limit 1",
 				dbesc($key)
 			);
 
-			if (count($r)) {
-				/*if (function_exists("apc_store"))
-					apc_store($key, $r[0]['v'], 600);*/
-
+			if (count($r))
 				return $r[0]['v'];
-			}
+
 			return null;
 		}
 
-		public static function set($key,$value) {
+		public static function set($key,$value, $duration = CACHE_MONTH) {
 
-			q("REPLACE INTO `cache` (`k`,`v`,`updated`) VALUES ('%s','%s','%s')",
+			q("REPLACE INTO `cache` (`k`,`v`,`expire_mode`,`updated`) VALUES ('%s','%s',%d,'%s')",
 					dbesc($key),
 					dbesc($value),
+					intval($duration),
 					dbesc(datetime_convert()));
 
-			/*if (function_exists("apc_store"))
-				apc_store($key, $value, 600);*/
-
 		}
 
 
@@ -63,8 +55,17 @@
 
 
 		public static function clear(){
-			q("DELETE FROM `cache` WHERE `updated` < '%s'",
-				dbesc(datetime_convert('UTC','UTC',"now - 30 days")));
+			q("DELETE FROM `cache` WHERE `updated` < '%s' AND `expire_mode` = %d",
+				dbesc(datetime_convert('UTC','UTC',"now - 30 days")), intval(CACHE_MONTH));
+
+			q("DELETE FROM `cache` WHERE `updated` < '%s' AND `expire_mode` = %d",
+				dbesc(datetime_convert('UTC','UTC',"now - 7 days")), intval(CACHE_WEEK));
+
+			q("DELETE FROM `cache` WHERE `updated` < '%s' AND `expire_mode` = %d",
+				dbesc(datetime_convert('UTC','UTC',"now - 1 days")), intval(CACHE_DAY));
+
+			q("DELETE FROM `cache` WHERE `updated` < '%s' AND `expire_mode` = %d",
+				dbesc(datetime_convert('UTC','UTC',"now - 1 hours")), intval(CACHE_HOUR));
 		}
 
 	}
diff --git a/include/dbstructure.php b/include/dbstructure.php
index 2370b01bec..2b1ee84fda 100644
--- a/include/dbstructure.php
+++ b/include/dbstructure.php
@@ -364,6 +364,7 @@ function db_definition() {
 			"fields" => array(
 					"k" => array("type" => "varchar(255)", "not null" => "1", "primary" => "1"),
 					"v" => array("type" => "text", "not null" => "1"),
+					"expire_mode" => array("type" => "int(11)", "not null" => "1", "default" => "0"),
 					"updated" => array("type" => "datetime", "not null" => "1", "default" => "0000-00-00 00:00:00"),
 					),
 			"indexes" => array(
diff --git a/include/discover_poco.php b/include/discover_poco.php
index 4a17b49279..79958a8849 100644
--- a/include/discover_poco.php
+++ b/include/discover_poco.php
@@ -183,7 +183,7 @@ function discover_directory($search) {
 				poco_check($data["url"], $data["name"], $data["network"], $data["photo"], "", "", "", $jj->tags, $data["addr"], "", 0);
 			}
 		}
-	Cache::set("dirsearch:".$search, time());
+	Cache::set("dirsearch:".$search, time(), CACHE_DAY);
 }
 
 if (array_search(__file__,get_included_files())===0){
diff --git a/include/items.php b/include/items.php
index a2b2a0197b..f15e2a1fc5 100644
--- a/include/items.php
+++ b/include/items.php
@@ -969,7 +969,7 @@ function query_page_info($url, $no_photos = false, $photo = "", $keywords = fals
 	$data = Cache::get("parse_url:".$url);
 	if (is_null($data)){
 		$data = parseurl_getsiteinfo($url, true);
-		Cache::set("parse_url:".$url,serialize($data));
+		Cache::set("parse_url:".$url,serialize($data), CACHE_DAY);
 	} else
 		$data = unserialize($data);
 
diff --git a/include/oembed.php b/include/oembed.php
index b32cb512be..aec92bfa04 100755
--- a/include/oembed.php
+++ b/include/oembed.php
@@ -73,7 +73,7 @@ function oembed_fetch_url($embedurl, $no_rich_type = false){
 		if ($txt[0]!="{") $txt='{"type":"error"}';
 
 		//save in cache
-		Cache::set($a->videowidth . $embedurl,$txt);
+		Cache::set($a->videowidth . $embedurl,$txt, CACHE_DAY);
 
 	}
 
diff --git a/mod/parse_url.php b/mod/parse_url.php
index 50c6a15b0e..97eebb89ab 100644
--- a/mod/parse_url.php
+++ b/mod/parse_url.php
@@ -60,7 +60,7 @@ function parseurl_getsiteinfo_cached($url, $no_guessing = false, $do_oembed = tr
 
 	$data = parseurl_getsiteinfo($url, $no_guessing, $do_oembed);
 
-	Cache::set("parse_url:".$no_guessing.":".$do_oembed.":".$url,serialize($data));
+	Cache::set("parse_url:".$no_guessing.":".$do_oembed.":".$url,serialize($data), CACHE_DAY);
 
 	return $data;
 }
diff --git a/update.php b/update.php
index a2c8674028..761da7273d 100644
--- a/update.php
+++ b/update.php
@@ -1,6 +1,6 @@
 <?php
 
-define( 'UPDATE_VERSION' , 1187 );
+define( 'UPDATE_VERSION' , 1188 );
 
 /**
  *