diff --git a/include/acl_selectors.php b/include/acl_selectors.php
index f6c4f947ed..75a4985c89 100644
--- a/include/acl_selectors.php
+++ b/include/acl_selectors.php
@@ -135,7 +135,7 @@ function contact_selector($selname, $selclass, $preselected = false, $options) {
 		$o .= "<select name=\"{$selname}[]\" id=\"$selclass\" class=\"$selclass\" multiple=\"multiple\" size=\"" . $x['size'] . "$\" $tabindex >\r\n";
 
 	$r = q("SELECT `id`, `name`, `url`, `network` FROM `contact`
-		WHERE `uid` = %d AND `self` = 0 AND `blocked` = 0 AND `pending` = 0 AND `archive` = 0 AND `notify` != ''
+		WHERE `uid` = %d AND NOT `self` AND NOT `blocked` AND NOT `pending` AND NOT `archive` AND `notify` != ''
 		$sql_extra
 		ORDER BY `name` ASC ",
 		intval(local_user())
@@ -210,7 +210,7 @@ function contact_select($selname, $selclass, $preselected = false, $size = 4, $p
 		$o .= "<select name=\"{$selname}[]\" id=\"$selclass\" class=\"$selclass\" multiple=\"multiple\" size=\"$size\" $tabindex >\r\n";
 
 	$r = q("SELECT `id`, `name`, `url`, `network` FROM `contact`
-		WHERE `uid` = %d AND `self` = 0 AND `blocked` = 0 AND `pending` = 0 AND `archive` = 0 AND `notify` != ''
+		WHERE `uid` = %d AND NOT `self` AND NOT `blocked` AND NOT `pending` AND NOT `archive` AND `notify` != ''
 		$sql_extra
 		ORDER BY `name` ASC ",
 		intval(local_user())
@@ -449,8 +449,8 @@ function acl_lookup(&$a, $out_type = 'json') {
 	// autocomplete for editor mentions
 	if ($type=='' || $type=='c'){
 		$r = q("SELECT COUNT(*) AS c FROM `contact`
-				WHERE `uid` = %d AND `self` = 0
-				AND `blocked` = 0 AND `pending` = 0 AND `archive` = 0
+				WHERE `uid` = %d AND NOT `self`
+				AND NOT `blocked` AND NOT `pending` AND NOT `archive`
 				AND `notify` != '' $sql_extra2" ,
 			intval(local_user())
 		);
@@ -461,8 +461,8 @@ function acl_lookup(&$a, $out_type = 'json') {
 		// autocomplete for Private Messages
 
 		$r = q("SELECT COUNT(*) AS c FROM `contact`
-				WHERE `uid` = %d AND `self` = 0
-				AND `blocked` = 0 AND `pending` = 0 AND `archive` = 0
+				WHERE `uid` = %d AND NOT `self`
+				AND NOT `blocked` AND NOT `pending` AND NOT `archive`
 				AND `network` IN ('%s','%s','%s') $sql_extra2" ,
 			intval(local_user()),
 			dbesc(NETWORK_DFRN),
@@ -477,8 +477,8 @@ function acl_lookup(&$a, $out_type = 'json') {
 		// autocomplete for Contacts
 
 		$r = q("SELECT COUNT(*) AS c FROM `contact`
-				WHERE `uid` = %d AND `self` = 0
-				AND `pending` = 0 $sql_extra2" ,
+				WHERE `uid` = %d AND NOT `self`
+				AND NOT `pending` $sql_extra2" ,
 			intval(local_user())
 		);
 		$contact_count = (int)$r[0]['c'];
@@ -525,7 +525,7 @@ function acl_lookup(&$a, $out_type = 'json') {
 	if ($type==''){
 
 		$r = q("SELECT `id`, `name`, `nick`, `micro`, `network`, `url`, `attag`, `forum`, `prv` FROM `contact`
-			WHERE `uid` = %d AND `self` = 0 AND `blocked` = 0 AND `pending` = 0 AND `archive` = 0 AND `notify` != ''
+			WHERE `uid` = %d AND NOT `self` AND NOT `blocked` AND NOT `pending` AND NOT `archive` AND `notify` != ''
 			AND NOT (`network` IN ('%s', '%s'))
 			$sql_extra2
 			ORDER BY `name` ASC ",
@@ -536,7 +536,7 @@ function acl_lookup(&$a, $out_type = 'json') {
 	elseif ($type=='c'){
 
 		$r = q("SELECT `id`, `name`, `nick`, `micro`, `network`, `url`, `attag`, `forum`, `prv` FROM `contact`
-			WHERE `uid` = %d AND `self` = 0 AND `blocked` = 0 AND `pending` = 0 AND `archive` = 0 AND `notify` != ''
+			WHERE `uid` = %d AND NOT `self` AND NOT `blocked` AND NOT `pending` AND NOT `archive` AND `notify` != ''
 			AND NOT (`network` IN ('%s'))
 			$sql_extra2
 			ORDER BY `name` ASC ",
@@ -546,7 +546,7 @@ function acl_lookup(&$a, $out_type = 'json') {
 	}
 	elseif($type == 'm') {
 		$r = q("SELECT `id`, `name`, `nick`, `micro`, `network`, `url`, `attag` FROM `contact`
-			WHERE `uid` = %d AND `self` = 0 AND `blocked` = 0 AND `pending` = 0 AND `archive` = 0
+			WHERE `uid` = %d AND NOT `self` AND NOT `blocked` AND NOT `pending` AND NOT `archive`
 			AND `network` IN ('%s','%s','%s')
 			$sql_extra2
 			ORDER BY `name` ASC ",
diff --git a/include/cron.php b/include/cron.php
index e98239b829..97744ed27a 100644
--- a/include/cron.php
+++ b/include/cron.php
@@ -128,7 +128,7 @@ function cron_run(&$argv, &$argc){
 
 		proc_run(PRIORITY_LOW, 'include/expire.php');
 
-		proc_run(PRIORITY_LOW, 'include/dbclean.php');
+		proc_run(PRIORITY_MEDIUM, 'include/dbclean.php');
 
 		cron_update_photo_albums();
 	}
diff --git a/include/dbclean.php b/include/dbclean.php
index 29c4173080..c80e5a3be3 100644
--- a/include/dbclean.php
+++ b/include/dbclean.php
@@ -23,8 +23,8 @@ function dbclean_run(&$argv, &$argc) {
 		unset($db_host, $db_user, $db_pass, $db_data);
 	}
 
-	load_config('config');
-	load_config('system');
+	Config::load('config');
+	Config::load('system');
 
 	if (!Config::get('system', 'dbclean', false)) {
 		return;
@@ -36,7 +36,7 @@ function dbclean_run(&$argv, &$argc) {
 		$stage = 0;
 	}
 
-	if (get_config("system", "worker") AND ($stage == 0)) {
+	if (Config::get("system", "worker") AND ($stage == 0)) {
 		proc_run(PRIORITY_LOW, 'include/dbclean.php', 1);
 		proc_run(PRIORITY_LOW, 'include/dbclean.php', 2);
 		proc_run(PRIORITY_LOW, 'include/dbclean.php', 3);
@@ -57,11 +57,18 @@ function remove_orphans($stage = 0) {
 
 	$count = 0;
 
+	// With activated worker we split the deletion in many small tasks
+	if (Config::get("system", "worker")) {
+		$limit = 1000;
+	} else {
+		$limit = 10000;
+	}
+
 	if (($stage == 1) OR ($stage == 0)) {
 		logger("Deleting old global item entries from item table without user copy");
 		if ($db->q("SELECT `id` FROM `item` WHERE `uid` = 0
 				AND NOT EXISTS (SELECT `guid` FROM `item` AS `i` WHERE `item`.`guid` = `i`.`guid` AND `i`.`uid` != 0)
-				AND `received` < UTC_TIMESTAMP() - INTERVAL 90 DAY LIMIT 10000", true)) {
+				AND `received` < UTC_TIMESTAMP() - INTERVAL 90 DAY LIMIT ".intval($limit), true)) {
 			$count = $db->num_rows();
 			logger("found global item orphans: ".$count);
 			while ($orphan = $db->qfetch()) {
@@ -74,7 +81,7 @@ function remove_orphans($stage = 0) {
 
 	if (($stage == 2) OR ($stage == 0)) {
 		logger("Deleting items without parents");
-		if ($db->q("SELECT `id` FROM `item` WHERE NOT EXISTS (SELECT `id` FROM `item` AS `i` WHERE `item`.`parent` = `i`.`id`) LIMIT 10000", true)) {
+		if ($db->q("SELECT `id` FROM `item` WHERE NOT EXISTS (SELECT `id` FROM `item` AS `i` WHERE `item`.`parent` = `i`.`id`) LIMIT ".intval($limit), true)) {
 			$count = $db->num_rows();
 			logger("found item orphans without parents: ".$count);
 			while ($orphan = $db->qfetch()) {
@@ -87,7 +94,7 @@ function remove_orphans($stage = 0) {
 
 	if (($stage == 3) OR ($stage == 0)) {
 		logger("Deleting orphaned data from thread table");
-		if ($db->q("SELECT `iid` FROM `thread` WHERE NOT EXISTS (SELECT `id` FROM `item` WHERE `item`.`parent` = `thread`.`iid`)", true)) {
+		if ($db->q("SELECT `iid` FROM `thread` WHERE NOT EXISTS (SELECT `id` FROM `item` WHERE `item`.`parent` = `thread`.`iid`) LIMIT ".intval($limit), true)) {
 			$count = $db->num_rows();
 			logger("found thread orphans: ".$count);
 			while ($orphan = $db->qfetch()) {
@@ -100,7 +107,7 @@ function remove_orphans($stage = 0) {
 
 	if (($stage == 4) OR ($stage == 0)) {
 		logger("Deleting orphaned data from notify table");
-		if ($db->q("SELECT `iid` FROM `notify` WHERE NOT EXISTS (SELECT `id` FROM `item` WHERE `item`.`id` = `notify`.`iid`)", true)) {
+		if ($db->q("SELECT `iid` FROM `notify` WHERE NOT EXISTS (SELECT `id` FROM `item` WHERE `item`.`id` = `notify`.`iid`) LIMIT ".intval($limit), true)) {
 			$count = $db->num_rows();
 			logger("found notify orphans: ".$count);
 			while ($orphan = $db->qfetch()) {
@@ -113,7 +120,7 @@ function remove_orphans($stage = 0) {
 
 	if (($stage == 5) OR ($stage == 0)) {
 		logger("Deleting orphaned data from notify-threads table");
-		if ($db->q("SELECT `id` FROM `notify-threads` WHERE NOT EXISTS (SELECT `id` FROM `item` WHERE `item`.`parent` = `notify-threads`.`master-parent-item`)", true)) {
+		if ($db->q("SELECT `id` FROM `notify-threads` WHERE NOT EXISTS (SELECT `id` FROM `item` WHERE `item`.`parent` = `notify-threads`.`master-parent-item`) LIMIT ".intval($limit), true)) {
 			$count = $db->num_rows();
 			logger("found notify-threads orphans: ".$count);
 			while ($orphan = $db->qfetch()) {
@@ -127,7 +134,7 @@ function remove_orphans($stage = 0) {
 
 	if (($stage == 6) OR ($stage == 0)) {
 		logger("Deleting orphaned data from sign table");
-		if ($db->q("SELECT `iid` FROM `sign` WHERE NOT EXISTS (SELECT `id` FROM `item` WHERE `item`.`id` = `sign`.`iid`)", true)) {
+		if ($db->q("SELECT `iid` FROM `sign` WHERE NOT EXISTS (SELECT `id` FROM `item` WHERE `item`.`id` = `sign`.`iid`) LIMIT ".intval($limit), true)) {
 			$count = $db->num_rows();
 			logger("found sign orphans: ".$count);
 			while ($orphan = $db->qfetch()) {
@@ -141,7 +148,7 @@ function remove_orphans($stage = 0) {
 
 	if (($stage == 7) OR ($stage == 0)) {
 		logger("Deleting orphaned data from term table");
-		if ($db->q("SELECT `oid` FROM `term` WHERE NOT EXISTS (SELECT `id` FROM `item` WHERE `item`.`id` = `term`.`oid`)", true)) {
+		if ($db->q("SELECT `oid` FROM `term` WHERE NOT EXISTS (SELECT `id` FROM `item` WHERE `item`.`id` = `term`.`oid`) LIMIT ".intval($limit), true)) {
 			$count = $db->num_rows();
 			logger("found term orphans: ".$count);
 			while ($orphan = $db->qfetch()) {
@@ -153,8 +160,8 @@ function remove_orphans($stage = 0) {
 	}
 
 	// Call it again if not all entries were purged
-	if (($stage != 0) AND ($count > 0) AND get_config("system", "worker")) {
-		proc_run(PRIORITY_LOW, 'include/dbclean.php');
+	if (($stage != 0) AND ($count > 0) AND Config::get("system", "worker")) {
+		proc_run(PRIORITY_MEDIUM, 'include/dbclean.php');
 	}
 
 }
diff --git a/view/theme/frio/theme.php b/view/theme/frio/theme.php
index f9cbf79a6a..a2fde7b25f 100644
--- a/view/theme/frio/theme.php
+++ b/view/theme/frio/theme.php
@@ -219,8 +219,8 @@ function frio_remote_nav($a,&$nav) {
 		// empty the server url for local user because we won't need it
 		$server_url = '';
 		// user info
-		$r = q("SELECT `micro` FROM `contact` WHERE `uid` = %d AND `self` = 1", intval($a->user['uid']));
-		
+		$r = q("SELECT `micro` FROM `contact` WHERE `uid` = %d AND `self`", intval($a->user['uid']));
+
 		$r[0]['photo'] = (dbm::is_result($r) ? $a->remove_baseurl($r[0]['micro']) : "images/person-48.jpg");
 		$r[0]['name'] = $a->user['username'];
 
@@ -298,7 +298,7 @@ function frio_acl_lookup($a, &$results) {
 
 
 		$r = q("SELECT COUNT(*) AS `total` FROM `contact`
-			WHERE `uid` = %d AND `self` = 0 AND `pending` = 0 $sql_extra $sql_extra2 ",
+			WHERE `uid` = %d AND NOT `self` AND NOT `pending` $sql_extra $sql_extra2 ",
 			intval($_SESSION['uid']));
 		if (dbm::is_result($r)) {
 			$total = $r[0]["total"];
@@ -306,7 +306,7 @@ function frio_acl_lookup($a, &$results) {
 
 		$sql_extra3 = unavailable_networks();
 
-		$r = q("SELECT * FROM `contact` WHERE `uid` = %d AND `self` = 0 AND `pending` = 0 $sql_extra $sql_extra2 $sql_extra3 ORDER BY `name` ASC LIMIT 100 ",
+		$r = q("SELECT * FROM `contact` WHERE `uid` = %d AND NOT `self` AND NOT `pending` $sql_extra $sql_extra2 $sql_extra3 ORDER BY `name` ASC LIMIT 100 ",
 			intval($_SESSION['uid'])
 		);