X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FCore%2FWorker.php;h=efb90ae6b6ca570090cdf850ac32d1aebcf9f641;hb=061d959e7f1387432c38d580429ed9e612954ed6;hp=affcf8442dc8cc803e3a8cf0adf7526d089d9057;hpb=3aa77685fcccff9739384136b4894de43200fa8c;p=friendica.git

diff --git a/src/Core/Worker.php b/src/Core/Worker.php
index affcf8442d..efb90ae6b6 100644
--- a/src/Core/Worker.php
+++ b/src/Core/Worker.php
@@ -22,9 +22,12 @@ use Friendica\Util\Network;
 class Worker
 {
 	private static $up_start;
-	private static $db_duration;
+	private static $db_duration = 0;
+	private static $db_duration_count = 0;
+	private static $db_duration_write = 0;
+	private static $db_duration_stat = 0;
+	private static $lock_duration = 0;
 	private static $last_update;
-	private static $lock_duration;
 
 	/**
 	 * @brief Processes the tasks that are in the workerqueue table
@@ -37,6 +40,9 @@ class Worker
 	{
 		$a = \get_app();
 
+		// Ensure that all "strtotime" operations do run timezone independent
+		date_default_timezone_set('UTC');
+
 		self::$up_start = microtime(true);
 
 		// At first check the maximum load. We shouldn't continue with a high load
@@ -87,11 +93,7 @@ class Worker
 		$starttime = time();
 
 		// We fetch the next queue entry that is about to be executed
-		while ($r = self::workerProcess($passing_slow)) {
-			// When we are processing jobs with a lower priority, we don't refetch new jobs
-			// Otherwise fast jobs could wait behind slow ones and could be blocked.
-			$refetched = $passing_slow;
-
+		while ($r = self::workerProcess()) {
 			foreach ($r as $entry) {
 				// Assure that the priority is an integer value
 				$entry['priority'] = (int)$entry['priority'];
@@ -103,21 +105,14 @@ class Worker
 				}
 
 				// If possible we will fetch new jobs for this worker
-				if (!$refetched) {
-					$entries = self::totalEntries();
-					$deferred = self::deferredEntries();
-					if (Lock::acquire('worker_process', 0)) {
-						$stamp = (float)microtime(true);
-						$refetched = self::findWorkerProcesses($passing_slow, $entries, $deferred);
-						self::$db_duration += (microtime(true) - $stamp);
-						Lock::release('worker_process');
-					}
+				if (!self::getWaitingJobForPID() && Lock::acquire('worker_process', 0)) {
+					self::findWorkerProcesses();
+					Lock::release('worker_process');
 				}
 			}
 
 			// To avoid the quitting of multiple workers only one worker at a time will execute the check
 			if (Lock::acquire('worker', 0)) {
-				$stamp = (float)microtime(true);
 				// Count active workers and compare them with a maximum value that depends on the load
 				if (self::tooMuchWorkers()) {
 					Logger::log('Active worker limit reached, quitting.', Logger::DEBUG);
@@ -132,7 +127,6 @@ class Worker
 					return;
 				}
 				Lock::release('worker');
-				self::$db_duration += (microtime(true) - $stamp);
 			}
 
 			// Quit the worker once every 5 minutes
@@ -149,6 +143,20 @@ class Worker
 		Logger::log("Couldn't select a workerqueue entry, quitting process " . getmypid() . ".", Logger::DEBUG);
 	}
 
+	/**
+	 * @brief Check if non executed tasks do exist in the worker queue
+	 *
+	 * @return boolean Returns "true" if tasks are existing
+	 * @throws \Exception
+	 */
+	private static function entriesExists()
+	{
+		$stamp = (float)microtime(true);
+		$exists = DBA::exists('workerqueue', ["NOT `done` AND `pid` = 0 AND `next_try` < ?", DateTimeFormat::utcNow()]);
+		self::$db_duration += (microtime(true) - $stamp);
+		return $exists;
+	}
+
 	/**
 	 * @brief Returns the number of deferred entries in the worker queue
 	 *
@@ -157,7 +165,11 @@ class Worker
 	 */
 	private static function deferredEntries()
 	{
-		return DBA::count('workerqueue', ["NOT `done` AND `pid` = 0 AND `next_try` > ?", DateTimeFormat::utcNow()]);
+		$stamp = (float)microtime(true);
+		$count = DBA::count('workerqueue', ["NOT `done` AND `pid` = 0 AND `next_try` > ?", DateTimeFormat::utcNow()]);
+		self::$db_duration += (microtime(true) - $stamp);
+		self::$db_duration_count += (microtime(true) - $stamp);
+		return $count;
 	}
 
 	/**
@@ -168,7 +180,11 @@ class Worker
 	 */
 	private static function totalEntries()
 	{
-		return DBA::count('workerqueue', ['done' => false, 'pid' => 0]);
+		$stamp = (float)microtime(true);
+		$count = DBA::count('workerqueue', ['done' => false, 'pid' => 0]);
+		self::$db_duration += (microtime(true) - $stamp);
+		self::$db_duration_count += (microtime(true) - $stamp);
+		return $count;
 	}
 
 	/**
@@ -179,8 +195,10 @@ class Worker
 	 */
 	private static function highestPriority()
 	{
+		$stamp = (float)microtime(true);
 		$condition = ["`pid` = 0 AND NOT `done` AND `next_try` < ?", DateTimeFormat::utcNow()];
 		$workerqueue = DBA::selectFirst('workerqueue', ['priority'], $condition, ['order' => ['priority']]);
+		self::$db_duration += (microtime(true) - $stamp);
 		if (DBA::isResult($workerqueue)) {
 			return $workerqueue["priority"];
 		} else {
@@ -252,6 +270,7 @@ class Worker
 				$stamp = (float)microtime(true);
 				DBA::update('workerqueue', ['executed' => DateTimeFormat::utcNow()], ['pid' => $mypid, 'done' => false]);
 				self::$db_duration += (microtime(true) - $stamp);
+				self::$db_duration_write += (microtime(true) - $stamp);
 			}
 
 			array_shift($argv);
@@ -259,12 +278,12 @@ class Worker
 			self::execFunction($queue, $include, $argv, true);
 
 			$stamp = (float)microtime(true);
-
 			$condition = ["`id` = ? AND `next_try` < ?", $queue['id'], DateTimeFormat::utcNow()];
 			if (DBA::update('workerqueue', ['done' => true], $condition)) {
 				Config::set('system', 'last_worker_execution', DateTimeFormat::utcNow());
 			}
 			self::$db_duration = (microtime(true) - $stamp);
+			self::$db_duration_write += (microtime(true) - $stamp);
 
 			return true;
 		}
@@ -276,7 +295,10 @@ class Worker
 
 		if (!validate_include($include)) {
 			Logger::log("Include file ".$argv[0]." is not valid!");
+			$stamp = (float)microtime(true);
 			DBA::delete('workerqueue', ['id' => $queue["id"]]);
+			self::$db_duration = (microtime(true) - $stamp);
+			self::$db_duration_write += (microtime(true) - $stamp);
 			return true;
 		}
 
@@ -297,6 +319,7 @@ class Worker
 				$stamp = (float)microtime(true);
 				DBA::update('workerqueue', ['executed' => DateTimeFormat::utcNow()], ['pid' => $mypid, 'done' => false]);
 				self::$db_duration += (microtime(true) - $stamp);
+				self::$db_duration_write += (microtime(true) - $stamp);
 			}
 
 			self::execFunction($queue, $funcname, $argv, false);
@@ -306,9 +329,13 @@ class Worker
 				Config::set('system', 'last_worker_execution', DateTimeFormat::utcNow());
 			}
 			self::$db_duration = (microtime(true) - $stamp);
+			self::$db_duration_write += (microtime(true) - $stamp);
 		} else {
 			Logger::log("Function ".$funcname." does not exist");
+			$stamp = (float)microtime(true);
 			DBA::delete('workerqueue', ['id' => $queue["id"]]);
+			self::$db_duration = (microtime(true) - $stamp);
+			self::$db_duration_write += (microtime(true) - $stamp);
 		}
 
 		return true;
@@ -332,7 +359,9 @@ class Worker
 
 		$argc = count($argv);
 
-		$new_process_id = System::processID("wrk");
+		// Currently deactivated, since the new logger doesn't support this
+		//$new_process_id = System::processID("wrk");
+		$new_process_id = '';
 
 		Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." ".$queue["parameter"]." - Process PID: ".$new_process_id);
 
@@ -361,7 +390,7 @@ class Worker
 		$a->process_id = $new_process_id;
 		$a->queue = $queue;
 
-		$up_duration = number_format(microtime(true) - self::$up_start, 3);
+		$up_duration = microtime(true) - self::$up_start;
 
 		// Reset global data to avoid interferences
 		unset($_SESSION);
@@ -377,21 +406,27 @@ class Worker
 
 		$duration = (microtime(true) - $stamp);
 
-		self::$up_start = microtime(true);
-
 		/* With these values we can analyze how effective the worker is.
 		 * The database and rest time should be low since this is the unproductive time.
 		 * The execution time is the productive time.
 		 * By changing parameters like the maximum number of workers we can check the effectivness.
 		*/
 		Logger::log(
-			'DB: '.number_format(self::$db_duration, 2).
-			' - Lock: '.number_format(self::$lock_duration, 2).
-			' - Rest: '.number_format($up_duration - self::$db_duration - self::$lock_duration, 2).
-			' - Execution: '.number_format($duration, 2),
+			'DB: '.number_format(self::$db_duration - (self::$db_duration_count + self::$db_duration_write + self::$db_duration_stat), 4).
+			' - DB-Count: '.number_format(self::$db_duration_count, 4).
+			' - DB-Stat: '.number_format(self::$db_duration_stat, 4).
+			' - DB-Write: '.number_format(self::$db_duration_write, 4).
+			' - Lock: '.number_format(self::$lock_duration, 4).
+			' - Rest: '.number_format(max(0, $up_duration - (self::$db_duration + self::$lock_duration)), 4).
+			' - Execution: '.number_format($duration, 4),
 			Logger::DEBUG
 		);
 
+		self::$up_start = microtime(true);
+		self::$db_duration = 0;
+		self::$db_duration_count = 0;
+		self::$db_duration_stat = 0;
+		self::$db_duration_write = 0;
 		self::$lock_duration = 0;
 
 		if ($duration > 3600) {
@@ -404,7 +439,7 @@ class Worker
 			Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 2 minutes (".round($duration/60, 3).")", Logger::DEBUG);
 		}
 
-		Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - done in ".$duration." seconds. Process PID: ".$new_process_id);
+		Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - done in ".number_format($duration, 4)." seconds. Process PID: ".$new_process_id);
 
 		// Write down the performance values into the log
 		if (Config::get("system", "profiler")) {
@@ -506,7 +541,9 @@ class Worker
 				$max = $r["Value"];
 			}
 			// Or it can be granted. This overrides the system variable
+			$stamp = (float)microtime(true);
 			$r = DBA::p('SHOW GRANTS');
+			self::$db_duration += (microtime(true) - $stamp);
 			while ($grants = DBA::fetch($r)) {
 				$grant = array_pop($grants);
 				if (stristr($grant, "GRANT USAGE ON")) {
@@ -521,7 +558,9 @@ class Worker
 		// If $max is set we will use the processlist to determine the current number of connections
 		// The processlist only shows entries of the current user
 		if ($max != 0) {
+			$stamp = (float)microtime(true);
 			$r = DBA::p('SHOW PROCESSLIST');
+			self::$db_duration += (microtime(true) - $stamp);
 			$used = DBA::numRows($r);
 			DBA::close($r);
 
@@ -571,20 +610,25 @@ class Worker
 	 */
 	private static function killStaleWorkers()
 	{
+		$stamp = (float)microtime(true);
 		$entries = DBA::select(
 			'workerqueue',
 			['id', 'pid', 'executed', 'priority', 'parameter'],
 			['NOT `done` AND `pid` != 0'],
 			['order' => ['priority', 'created']]
 		);
+		self::$db_duration += (microtime(true) - $stamp);
 
 		while ($entry = DBA::fetch($entries)) {
 			if (!posix_kill($entry["pid"], 0)) {
+				$stamp = (float)microtime(true);
 				DBA::update(
 					'workerqueue',
 					['executed' => DBA::NULL_DATETIME, 'pid' => 0],
 					['id' => $entry["id"]]
 				);
+				self::$db_duration += (microtime(true) - $stamp);
+				self::$db_duration_write += (microtime(true) - $stamp);
 			} else {
 				// Kill long running processes
 				// Check if the priority is in a valid range
@@ -616,11 +660,14 @@ class Worker
 					} elseif ($entry["priority"] != PRIORITY_CRITICAL) {
 						$new_priority = PRIORITY_NEGLIGIBLE;
 					}
+					$stamp = (float)microtime(true);
 					DBA::update(
 						'workerqueue',
 						['executed' => DBA::NULL_DATETIME, 'created' => DateTimeFormat::utcNow(), 'priority' => $new_priority, 'pid' => 0],
 						['id' => $entry["id"]]
 					);
+					self::$db_duration += (microtime(true) - $stamp);
+					self::$db_duration_write += (microtime(true) - $stamp);
 				} else {
 					Logger::log("Worker process ".$entry["pid"]." (".substr(json_encode($argv), 0, 50).") now runs for ".round($duration)." of ".$max_duration." allowed minutes. That's okay.", Logger::DEBUG);
 				}
@@ -634,7 +681,7 @@ class Worker
 	 * @return bool Are there too much workers running?
 	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 	 */
-	public static function tooMuchWorkers()
+	private static function tooMuchWorkers()
 	{
 		$queues = Config::get("system", "worker_queues", 4);
 
@@ -659,10 +706,19 @@ class Worker
 			$processlist = '';
 
 			if (Config::get('system', 'worker_jpm')) {
-				$intervals = [1, 10, 60];
+				$intervals = explode(',', Config::get('system', 'worker_jpm_range'));
 				$jobs_per_minute = [];
 				foreach ($intervals as $interval) {
+					if ($interval == 0) {
+						continue;
+					} else {
+						$interval = (int)$interval;
+					}
+
+					$stamp = (float)microtime(true);
 					$jobs = DBA::p("SELECT COUNT(*) AS `jobs` FROM `workerqueue` WHERE `done` AND `executed` > UTC_TIMESTAMP() - INTERVAL ? MINUTE", $interval);
+					self::$db_duration += (microtime(true) - $stamp);
+					//self::$db_duration_stat += (microtime(true) - $stamp);
 					if ($job = DBA::fetch($jobs)) {
 						$jobs_per_minute[$interval] = number_format($job['jobs'] / $interval, 0);
 					}
@@ -671,33 +727,54 @@ class Worker
 				$processlist = ' - jpm: '.implode('/', $jobs_per_minute);
 			}
 
-			if (Config::get('system', 'worker_debug')) {
-				// Create a list of queue entries grouped by their priority
-				$listitem = [0 => ''];
+			// Create a list of queue entries grouped by their priority
+			$listitem = [0 => ''];
 
-				$idle_workers = $active;
+			$idle_workers = $active;
 
+			$deferred = self::deferredEntries();
+
+			if (Config::get('system', 'worker_debug')) {
+				$waiting_processes = 0;
 				// Now adding all processes with workerqueue entries
-				$entries = DBA::p("SELECT COUNT(*) AS `entries`, `priority` FROM `workerqueue` WHERE NOT `done` GROUP BY `priority`");
-				while ($entry = DBA::fetch($entries)) {
+				$stamp = (float)microtime(true);
+				$jobs = DBA::p("SELECT COUNT(*) AS `entries`, `priority` FROM `workerqueue` WHERE NOT `done` AND `next_try` < ? GROUP BY `priority`", DateTimeFormat::utcNow());
+				self::$db_duration += (microtime(true) - $stamp);
+				self::$db_duration_stat += (microtime(true) - $stamp);
+				while ($entry = DBA::fetch($jobs)) {
+					$stamp = (float)microtime(true);
 					$processes = DBA::p("SELECT COUNT(*) AS `running` FROM `process` INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` WHERE NOT `done` AND `priority` = ?", $entry["priority"]);
+					self::$db_duration += (microtime(true) - $stamp);
+					self::$db_duration_stat += (microtime(true) - $stamp);
 					if ($process = DBA::fetch($processes)) {
 						$idle_workers -= $process["running"];
+						$waiting_processes += $entry["entries"];
 						$listitem[$entry["priority"]] = $entry["priority"].":".$process["running"]."/".$entry["entries"];
 					}
 					DBA::close($processes);
 				}
-				DBA::close($entries);
-
-				$listitem[0] = "0:" . max(0, $idle_workers);
+				DBA::close($jobs);
+				$entries = $deferred + $waiting_processes;
+			} else {
+				$entries = self::totalEntries();
+				$waiting_processes = max(0, $entries - $deferred);
+				$stamp = (float)microtime(true);
+				$jobs = DBA::p("SELECT COUNT(*) AS `running`, `priority` FROM `process` INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done` GROUP BY `priority` ORDER BY `priority`");
+				self::$db_duration += (microtime(true) - $stamp);
+				self::$db_duration_stat += (microtime(true) - $stamp);
 
-				$processlist .= ' ('.implode(', ', $listitem).')';
+				while ($entry = DBA::fetch($jobs)) {
+					$idle_workers -= $entry["running"];
+					$listitem[$entry["priority"]] = $entry["priority"].":".$entry["running"];
+				}
+				DBA::close($jobs);
 			}
 
-			$deferred = self::deferredEntries();
-			$entries = max(self::totalEntries() - $deferred, 0);
+			$listitem[0] = "0:" . max(0, $idle_workers);
+
+			$processlist .= ' ('.implode(', ', $listitem).')';
 
-			if (Config::get("system", "worker_fastlane", false) && ($queues > 0) && ($entries > 0) && ($active >= $queues)) {
+			if (Config::get("system", "worker_fastlane", false) && ($queues > 0) && self::entriesExists() && ($active >= $queues)) {
 				$top_priority = self::highestPriority();
 				$high_running = self::processWithPriorityActive($top_priority);
 
@@ -707,7 +784,7 @@ class Worker
 				}
 			}
 
-			Logger::log("Load: " . $load ."/" . $maxsysload . " - processes: " . $deferred . "/" . $active . "/" . $entries . $processlist . " - maximum: " . $queues . "/" . $maxqueues, Logger::DEBUG);
+			Logger::log("Load: " . $load ."/" . $maxsysload . " - processes: " . $deferred . "/" . $active . "/" . $waiting_processes . $processlist . " - maximum: " . $queues . "/" . $maxqueues, Logger::DEBUG);
 
 			// Are there fewer workers running as possible? Then fork a new one.
 			if (!Config::get("system", "worker_dont_fork", false) && ($queues > ($active + 1)) && ($entries > 1)) {
@@ -736,199 +813,190 @@ class Worker
 	 */
 	private static function activeWorkers()
 	{
-		return DBA::count('process', ['command' => 'Worker.php']);
+		$stamp = (float)microtime(true);
+		$count = DBA::count('process', ['command' => 'Worker.php']);
+		self::$db_duration += (microtime(true) - $stamp);
+		return $count;
 	}
 
-	/**
-	 * @brief Check if we should pass some slow processes
-	 *
-	 * When the active processes of the highest priority are using more than 2/3
-	 * of all processes, we let pass slower processes.
-	 *
-	 * @param string $highest_priority Returns the currently highest priority
-	 * @return bool We let pass a slower process than $highest_priority
-	 * @throws \Exception
-	 */
-	private static function passingSlow(&$highest_priority)
+	private static function getWaitingJobForPID()
 	{
-		$highest_priority = 0;
+		$stamp = (float)microtime(true);
+		$r = DBA::select('workerqueue', [], ['pid' => getmypid(), 'done' => false]);
+		self::$db_duration += (microtime(true) - $stamp);
+		if (DBA::isResult($r)) {
+			return DBA::toArray($r);
+		}
+		DBA::close($r);
 
-		$r = DBA::p(
-			"SELECT `priority`
-				FROM `process`
-				INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done`"
-		);
+		return false;
+	}
 
-		// No active processes at all? Fine
-		if (!DBA::isResult($r)) {
-			return false;
+	private static function nextProcess()
+	{
+		$priority = self::nextPriority();
+		if (empty($priority)) {
+			Logger::log('No tasks found', Logger::DEBUG);
+			return [];
 		}
-		$priorities = [];
-		while ($line = DBA::fetch($r)) {
-			$priorities[] = $line["priority"];
+
+		if ($priority <= PRIORITY_MEDIUM) {
+			$limit = Config::get('system', 'worker_fetch_limit', 1);
+		} else {
+			$limit = 1;
 		}
-		DBA::close($r);
 
-		// Should not happen
-		if (count($priorities) == 0) {
-			return false;
+		$ids = [];
+		$stamp = (float)microtime(true);
+		$condition = ["`priority` = ? AND `pid` = 0 AND NOT `done` AND `next_try` < ?", $priority, DateTimeFormat::utcNow()];
+		$tasks = DBA::select('workerqueue', ['id'], $condition, ['limit' => $limit, 'order' => ['created']]);
+		self::$db_duration += (microtime(true) - $stamp);
+		while ($task = DBA::fetch($tasks)) {
+			$ids[] = $task['id'];
 		}
-		$highest_priority = min($priorities);
+		DBA::close($tasks);
 
-		// The highest process is already the slowest one?
-		// Then we quit
-		if ($highest_priority == PRIORITY_NEGLIGIBLE) {
-			return false;
+		Logger::log('Found task(s) ' . implode(', ', $ids) . ' with priority ' .$priority, Logger::DEBUG);
+		return $ids;
+	}
+
+	private static function nextPriority()
+	{
+		$waiting = [];
+		$priorities = [PRIORITY_CRITICAL, PRIORITY_HIGH, PRIORITY_MEDIUM, PRIORITY_LOW, PRIORITY_NEGLIGIBLE];
+		foreach ($priorities as $priority) {
+			$stamp = (float)microtime(true);
+			if (DBA::exists('workerqueue', ["`priority` = ? AND `pid` = 0 AND NOT `done` AND `next_try` < ?", $priority, DateTimeFormat::utcNow()])) {
+				$waiting[$priority] = true;
+			}
+			self::$db_duration += (microtime(true) - $stamp);
+		}
+
+		if (!empty($waiting[PRIORITY_CRITICAL])) {
+			return PRIORITY_CRITICAL;
 		}
-		$high = 0;
+
+		$running = [];
+		$running_total = 0;
+		$stamp = (float)microtime(true);
+		$processes = DBA::p("SELECT COUNT(DISTINCT(`process`.`pid`)) AS `running`, `priority` FROM `process`
+			INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid`
+			WHERE NOT `done` GROUP BY `priority`");
+		self::$db_duration += (microtime(true) - $stamp);
+		while ($process = DBA::fetch($processes)) {
+			$running[$process['priority']] = $process['running'];
+			$running_total += $process['running'];
+		}
+		DBA::close($processes);
+
 		foreach ($priorities as $priority) {
-			if ($priority == $highest_priority) {
-				++$high;
+			if (!empty($waiting[$priority]) && empty($running[$priority])) {
+				Logger::log('No running worker found with priority ' . $priority . ' - assigning it.', Logger::DEBUG);
+				return $priority;
 			}
 		}
-		Logger::log("Highest priority: ".$highest_priority." Total processes: ".count($priorities)." Count high priority processes: ".$high, Logger::DEBUG);
-		$passing_slow = (($high/count($priorities)) > (2/3));
 
-		if ($passing_slow) {
-			Logger::log("Passing slower processes than priority ".$highest_priority, Logger::DEBUG);
+		$active = max(self::activeWorkers(), $running_total);
+		$priorities = max(count($waiting), count($running));
+		$exponent = 2;
+
+		$total = 0;
+		for ($i = 1; $i <= $priorities; ++$i) {
+			$total += pow($i, $exponent);
 		}
-		return $passing_slow;
+
+		$limit = [];
+		for ($i = 1; $i <= $priorities; ++$i) {
+			$limit[$priorities - $i] = max(1, round($active * (pow($i, $exponent) / $total)));
+		}
+
+		$i = 0;
+		foreach ($running as $priority => $workers) {
+			if ($workers < $limit[$i++]) {
+				Logger::log('Priority ' . $priority . ' has got ' . $workers . ' workers out of a limit of ' . $limit[$i - 1], Logger::DEBUG);
+				return $priority;
+			}
+		}
+
+		if (!empty($waiting)) {
+			$priority =  array_shift(array_keys($waiting));
+			Logger::log('No underassigned priority found, now taking the highest priority (' . $priority . ').', Logger::DEBUG);
+			return $priority;
+		}
+
+		return false;
 	}
 
 	/**
 	 * @brief Find and claim the next worker process for us
 	 *
-	 * @param boolean $passing_slow Returns if we had passed low priority processes
-	 * @param integer $entries Total number of queue entries
-	 * @param integer $deferred Number of deferred queue entries
 	 * @return boolean Have we found something?
 	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 	 */
-	private static function findWorkerProcesses(&$passing_slow, $entries, $deferred)
+	private static function findWorkerProcesses()
 	{
 		$mypid = getmypid();
 
-		// Check if we should pass some low priority process
-		$highest_priority = 0;
-		$found = false;
-		$passing_slow = false;
-
-		// The higher the number of parallel workers, the more we prefetch to prevent concurring access
-		// We decrease the limit with the number of entries left in the queue
-		$worker_queues = Config::get("system", "worker_queues", 4);
-		$queue_length = Config::get('system', 'worker_fetch_limit', 1);
-		$lower_job_limit = $worker_queues * $queue_length * 2;
-		$entries = max($entries - $deferred, 0);
-
-		// Now do some magic
-		$exponent = 2;
-		$slope = $queue_length / pow($lower_job_limit, $exponent);
-		$limit = min($queue_length, ceil($slope * pow($entries, $exponent)));
-
-		Logger::log('Deferred: ' . $deferred . ' - Total: ' . $entries . ' - Maximum: ' . $queue_length . ' - jobs per queue: ' . $limit, Logger::DEBUG);
-		$ids = [];
-		if (self::passingSlow($highest_priority)) {
-			// Are there waiting processes with a higher priority than the currently highest?
-			$result = DBA::select(
-				'workerqueue',
-				['id'],
-				["`pid` = 0 AND `priority` < ? AND NOT `done` AND `next_try` < ?",
-				$highest_priority, DateTimeFormat::utcNow()],
-				['limit' => $limit, 'order' => ['priority', 'created']]
-			);
-
-			while ($id = DBA::fetch($result)) {
-				$ids[] = $id["id"];
-			}
-			DBA::close($result);
-
-			$found = (count($ids) > 0);
-
-			if (!$found) {
-				// Give slower processes some processing time
-				$result = DBA::select(
-					'workerqueue',
-					['id'],
-					["`pid` = 0 AND `priority` > ? AND NOT `done` AND `next_try` < ?",
-					$highest_priority, DateTimeFormat::utcNow()],
-					['limit' => $limit, 'order' => ['priority', 'created']]
-				);
-
-				while ($id = DBA::fetch($result)) {
-					$ids[] = $id["id"];
-				}
-				DBA::close($result);
-
-				$found = (count($ids) > 0);
-				$passing_slow = $found;
-			}
-		}
+		$ids = self::nextProcess();
 
-		// If there is no result (or we shouldn't pass lower processes) we check without priority limit
-		if (!$found) {
+		// If there is no result we check without priority limit
+		if (empty($ids)) {
+			$stamp = (float)microtime(true);
 			$result = DBA::select(
 				'workerqueue',
 				['id'],
 				["`pid` = 0 AND NOT `done` AND `next_try` < ?",
 				DateTimeFormat::utcNow()],
-				['limit' => $limit, 'order' => ['priority', 'created']]
+				['limit' => 1, 'order' => ['priority', 'created']]
 			);
+			self::$db_duration += (microtime(true) - $stamp);
 
 			while ($id = DBA::fetch($result)) {
 				$ids[] = $id["id"];
 			}
 			DBA::close($result);
-
-			$found = (count($ids) > 0);
 		}
 
-		if ($found) {
+		if (!empty($ids)) {
+			$stamp = (float)microtime(true);
 			$condition = "`id` IN (".substr(str_repeat("?, ", count($ids)), 0, -2).") AND `pid` = 0 AND NOT `done`";
 			array_unshift($ids, $condition);
 			DBA::update('workerqueue', ['executed' => DateTimeFormat::utcNow(), 'pid' => $mypid], $ids);
+			self::$db_duration += (microtime(true) - $stamp);
+			self::$db_duration_write += (microtime(true) - $stamp);
 		}
 
-		return $found;
+		return !empty($ids);
 	}
 
 	/**
 	 * @brief Returns the next worker process
 	 *
-	 * @param boolean $passing_slow Returns if we had passed low priority processes
 	 * @return string SQL statement
 	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 	 */
-	public static function workerProcess(&$passing_slow)
+	public static function workerProcess()
 	{
-		$stamp = (float)microtime(true);
-
 		// There can already be jobs for us in the queue.
-		$r = DBA::select('workerqueue', [], ['pid' => getmypid(), 'done' => false]);
-		if (DBA::isResult($r)) {
-			self::$db_duration += (microtime(true) - $stamp);
-			return DBA::toArray($r);
+		$waiting = self::getWaitingJobForPID();
+		if (!empty($waiting)) {
+			return $waiting;
 		}
-		DBA::close($r);
 
 		$stamp = (float)microtime(true);
-
-		// Counting the rows outside the lock reduces the lock time
-		$entries = self::totalEntries();
-		$deferred = self::deferredEntries();
-
 		if (!Lock::acquire('worker_process')) {
 			return false;
 		}
-		self::$lock_duration = (microtime(true) - $stamp);
+		self::$lock_duration += (microtime(true) - $stamp);
 
-		$stamp = (float)microtime(true);
-		$found = self::findWorkerProcesses($passing_slow, $entries, $deferred);
-		self::$db_duration += (microtime(true) - $stamp);
+		$found = self::findWorkerProcesses();
 
 		Lock::release('worker_process');
 
 		if ($found) {
+			$stamp = (float)microtime(true);
 			$r = DBA::select('workerqueue', [], ['pid' => getmypid(), 'done' => false]);
+			self::$db_duration += (microtime(true) - $stamp);
 			return DBA::toArray($r);
 		}
 		return false;
@@ -943,7 +1011,10 @@ class Worker
 	{
 		$mypid = getmypid();
 
+		$stamp = (float)microtime(true);
 		DBA::update('workerqueue', ['executed' => DBA::NULL_DATETIME, 'pid' => 0], ['pid' => $mypid, 'done' => false]);
+		self::$db_duration += (microtime(true) - $stamp);
+		self::$db_duration_write += (microtime(true) - $stamp);
 	}
 
 	/**
@@ -1022,9 +1093,12 @@ class Worker
 		$timeout = Config::get("system", "frontend_worker_timeout", 10);
 
 		/// @todo We should clean up the corresponding workerqueue entries as well
+		$stamp = (float)microtime(true);
 		$condition = ["`created` < ? AND `command` = 'worker.php'",
 				DateTimeFormat::utc("now - ".$timeout." minutes")];
 		DBA::delete('process', $condition);
+		self::$db_duration = (microtime(true) - $stamp);
+		self::$db_duration_write += (microtime(true) - $stamp);
 	}
 
 	/**
@@ -1200,8 +1274,11 @@ class Worker
 
 		Logger::log('Defer execution ' . $retrial . ' of id ' . $id . ' to ' . $next . ' - priority old/new: ' . $queue['priority'] . '/' . $priority, Logger::DEBUG);
 
+		$stamp = (float)microtime(true);
 		$fields = ['retrial' => $retrial + 1, 'next_try' => $next, 'executed' => DBA::NULL_DATETIME, 'pid' => 0, 'priority' => $priority];
 		DBA::update('workerqueue', $fields, ['id' => $id]);
+		self::$db_duration += (microtime(true) - $stamp);
+		self::$db_duration_write += (microtime(true) - $stamp);
 	}
 
 	/**
@@ -1241,7 +1318,10 @@ class Worker
 	 */
 	public static function IPCSetJobState($jobs)
 	{
+		$stamp = (float)microtime(true);
 		DBA::update('worker-ipc', ['jobs' => $jobs], ['key' => 1], true);
+		self::$db_duration += (microtime(true) - $stamp);
+		self::$db_duration_write += (microtime(true) - $stamp);
 	}
 
 	/**
@@ -1253,7 +1333,9 @@ class Worker
 	 */
 	public static function IPCJobsExists()
 	{
+		$stamp = (float)microtime(true);
 		$row = DBA::selectFirst('worker-ipc', ['jobs'], ['key' => 1]);
+		self::$db_duration += (microtime(true) - $stamp);
 
 		// When we don't have a row, no job is running
 		if (!DBA::isResult($row)) {