]> git.mxchange.org Git - friendica.git/blobdiff - src/Core/Worker.php
Adding a cooldown phase for the daemon
[friendica.git] / src / Core / Worker.php
index c5d60f14da26333c65e56c418953de5879dcbc28..1cde61351c0f2fc0ce9a30fdc1f2b694b3226b70 100644 (file)
@@ -1,26 +1,47 @@
 <?php
 /**
- * @file src/Core/Worker.php
+ * @copyright Copyright (C) 2020, Friendica
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
  */
+
 namespace Friendica\Core;
 
-use Friendica\BaseObject;
+use Friendica\Core;
 use Friendica\Database\DBA;
+use Friendica\DI;
 use Friendica\Model\Process;
 use Friendica\Util\DateTimeFormat;
-use Friendica\Util\Network;
 
 /**
- * @file src/Core/Worker.php
- *
- * @brief Contains the class for the worker background job processing
- */
-
-/**
- * @brief Worker methods
+ * Contains the class for the worker background job processing
  */
 class Worker
 {
+       const STATE_STARTUP    = 1; // Worker is in startup. This takes most time.
+       const STATE_LONG_LOOP  = 2; // Worker is processing the whole - long - loop.
+       const STATE_REFETCH    = 3; // Worker had refetched jobs in the execution loop.
+       const STATE_SHORT_LOOP = 4; // Worker is processing preassigned jobs, thus saving much time.
+
+       const FAST_COMMANDS = ['APDelivery', 'Delivery', 'CreateShadowEntry'];
+
+       const LOCK_PROCESS = 'worker_process';
+       const LOCK_WORKER = 'worker';
+
        private static $up_start;
        private static $db_duration = 0;
        private static $db_duration_count = 0;
@@ -28,9 +49,10 @@ class Worker
        private static $db_duration_stat = 0;
        private static $lock_duration = 0;
        private static $last_update;
+       private static $state;
 
        /**
-        * @brief Processes the tasks that are in the workerqueue table
+        * Processes the tasks that are in the workerqueue table
         *
         * @param boolean $run_cron Should the cron processes be executed?
         * @return void
@@ -38,16 +60,14 @@ class Worker
         */
        public static function processQueue($run_cron = true)
        {
-               $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
-               if ($a->isMaxLoadReached()) {
-                       Logger::log('Pre check: maximum load reached, quitting.', Logger::DEBUG);
+               if (DI::process()->isMaxLoadReached()) {
+                       Logger::info('Pre check: maximum load reached, quitting.');
                        return;
                }
 
@@ -55,33 +75,14 @@ class Worker
                self::startProcess();
 
                // Kill stale processes every 5 minutes
-               $last_cleanup = Config::get('system', 'worker_last_cleaned', 0);
+               $last_cleanup = DI::config()->get('system', 'worker_last_cleaned', 0);
                if (time() > ($last_cleanup + 300)) {
-                       Config::set('system', 'worker_last_cleaned', time());
+                       DI::config()->set('system', 'worker_last_cleaned', time());
                        self::killStaleWorkers();
                }
 
-               // Count active workers and compare them with a maximum value that depends on the load
-               if (self::tooMuchWorkers()) {
-                       Logger::log('Pre check: Active worker limit reached, quitting.', Logger::DEBUG);
-                       return;
-               }
-
-               // Do we have too few memory?
-               if ($a->isMinMemoryReached()) {
-                       Logger::log('Pre check: Memory limit reached, quitting.', Logger::DEBUG);
-                       return;
-               }
-
-               // Possibly there are too much database connections
-               if (self::maxConnectionsReached()) {
-                       Logger::log('Pre check: maximum connections reached, quitting.', Logger::DEBUG);
-                       return;
-               }
-
-               // Possibly there are too much database processes that block the system
-               if ($a->isMaxProcessesReached()) {
-                       Logger::log('Pre check: maximum processes reached, quitting.', Logger::DEBUG);
+               // Check if the system is ready
+               if (!self::isReady()) {
                        return;
                }
 
@@ -91,76 +92,112 @@ class Worker
                }
 
                $starttime = time();
-
-               $entries = 0;
-               $deferred = 0;
+               self::$state = self::STATE_STARTUP;
 
                // We fetch the next queue entry that is about to be executed
-               while ($r = self::workerProcess($passing_slow, $entries, $deferred)) {
-                       // 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()) {
+                       $refetched = false;
                        foreach ($r as $entry) {
                                // Assure that the priority is an integer value
                                $entry['priority'] = (int)$entry['priority'];
 
                                // The work will be done
                                if (!self::execute($entry)) {
-                                       Logger::log('Process execution failed, quitting.', Logger::DEBUG);
+                                       Logger::info('Process execution failed, quitting.');
                                        return;
                                }
 
-                               // If possible we will fetch new jobs for this worker
-                               if (!$refetched) {
-                                       $entries = self::totalEntries();
-                                       $deferred = self::deferredEntries();
-                                       if (Lock::acquire('worker_process', 0)) {
-                                               $refetched = self::findWorkerProcesses($passing_slow, $entries, $deferred);
-                                               Lock::release('worker_process');
-                                       }
+                               // Trying to fetch new processes - but only once when successful
+                               if (!$refetched && DI::lock()->acquire(self::LOCK_PROCESS, 0)) {
+                                       self::findWorkerProcesses();
+                                       DI::lock()->release(self::LOCK_PROCESS);
+                                       self::$state = self::STATE_REFETCH;
+                                       $refetched = true;
+                               } else {
+                                       self::$state = self::STATE_SHORT_LOOP;
                                }
                        }
 
                        // To avoid the quitting of multiple workers only one worker at a time will execute the check
-                       if (Lock::acquire('worker', 0)) {
+                       if (!self::getWaitingJobForPID()) {
+                               self::$state = self::STATE_LONG_LOOP;
+
+                               if (DI::lock()->acquire(self::LOCK_WORKER, 0)) {
                                // Count active workers and compare them with a maximum value that depends on the load
-                               if (self::tooMuchWorkers($entries, $deferred)) {
-                                       Logger::log('Active worker limit reached, quitting.', Logger::DEBUG);
-                                       Lock::release('worker');
-                                       return;
-                               }
+                                       if (self::tooMuchWorkers()) {
+                                               Logger::info('Active worker limit reached, quitting.');
+                                               DI::lock()->release(self::LOCK_WORKER);
+                                               return;
+                                       }
 
-                               // Check free memory
-                               if ($a->isMinMemoryReached()) {
-                                       Logger::log('Memory limit reached, quitting.', Logger::DEBUG);
-                                       Lock::release('worker');
-                                       return;
+                                       // Check free memory
+                                       if (DI::process()->isMinMemoryReached()) {
+                                               Logger::info('Memory limit reached, quitting.');
+                                               DI::lock()->release(self::LOCK_WORKER);
+                                               return;
+                                       }
+                                       DI::lock()->release(self::LOCK_WORKER);
                                }
-                               Lock::release('worker');
                        }
 
-                       // Quit the worker once every 5 minutes
-                       if (time() > ($starttime + 300)) {
-                               Logger::log('Process lifetime reached, quitting.', Logger::DEBUG);
+                       // Quit the worker once every cron interval
+                       if (time() > ($starttime + (DI::config()->get('system', 'cron_interval') * 60))) {
+                               Logger::info('Process lifetime reached, respawning.');
+                               self::spawnWorker();
                                return;
                        }
                }
 
                // Cleaning up. Possibly not needed, but it doesn't harm anything.
-               if (Config::get('system', 'worker_daemon_mode', false)) {
+               if (DI::config()->get('system', 'worker_daemon_mode', false)) {
                        self::IPCSetJobState(false);
                }
-               Logger::log("Couldn't select a workerqueue entry, quitting process " . getmypid() . ".", Logger::DEBUG);
+               Logger::info("Couldn't select a workerqueue entry, quitting process", ['pid' => getmypid()]);
        }
 
        /**
-        * @brief Check if non executed tasks do exist in the worker queue
+        * Checks if the system is ready.
+        *
+        * Several system parameters like memory, connections and processes are checked.
+        *
+        * @return boolean
+        */
+       public static function isReady()
+       {
+               // Count active workers and compare them with a maximum value that depends on the load
+               if (self::tooMuchWorkers()) {
+                       Logger::info('Active worker limit reached, quitting.');
+                       return false;
+               }
+
+               // Do we have too few memory?
+               if (DI::process()->isMinMemoryReached()) {
+                       Logger::info('Memory limit reached, quitting.');
+                       return false;
+               }
+
+               // Possibly there are too much database connections
+               if (self::maxConnectionsReached()) {
+                       Logger::info('Maximum connections reached, quitting.');
+                       return false;
+               }
+
+               // Possibly there are too much database processes that block the system
+               if (DI::process()->isMaxProcessesReached()) {
+                       Logger::info('Maximum processes reached, quitting.');
+                       return false;
+               }
+               
+               return true;
+       }
+
+       /**
+        * 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()
+       public static function entriesExists()
        {
                $stamp = (float)microtime(true);
                $exists = DBA::exists('workerqueue', ["NOT `done` AND `pid` = 0 AND `next_try` < ?", DateTimeFormat::utcNow()]);
@@ -169,7 +206,7 @@ class Worker
        }
 
        /**
-        * @brief Returns the number of deferred entries in the worker queue
+        * Returns the number of deferred entries in the worker queue
         *
         * @return integer Number of deferred entries in the worker queue
         * @throws \Exception
@@ -177,14 +214,14 @@ class Worker
        private static function deferredEntries()
        {
                $stamp = (float)microtime(true);
-               $count = DBA::count('workerqueue', ["NOT `done` AND `pid` = 0 AND `next_try` > ?", DateTimeFormat::utcNow()]);
+               $count = DBA::count('workerqueue', ["NOT `done` AND `pid` = 0 AND `retrial` > ?", 0]);
                self::$db_duration += (microtime(true) - $stamp);
                self::$db_duration_count += (microtime(true) - $stamp);
                return $count;
        }
 
        /**
-        * @brief Returns the number of non executed entries in the worker queue
+        * Returns the number of non executed entries in the worker queue
         *
         * @return integer Number of non executed entries in the worker queue
         * @throws \Exception
@@ -199,7 +236,7 @@ class Worker
        }
 
        /**
-        * @brief Returns the highest priority in the worker queue that isn't executed
+        * Returns the highest priority in the worker queue that isn't executed
         *
         * @return integer Number of active worker processes
         * @throws \Exception
@@ -218,7 +255,7 @@ class Worker
        }
 
        /**
-        * @brief Returns if a process with the given priority is running
+        * Returns if a process with the given priority is running
         *
         * @param integer $priority The priority that should be checked
         *
@@ -232,7 +269,7 @@ class Worker
        }
 
        /**
-        * @brief Execute a worker entry
+        * Execute a worker entry
         *
         * @param array $queue Workerqueue entry
         *
@@ -241,29 +278,31 @@ class Worker
         */
        public static function execute($queue)
        {
-               $a = \get_app();
-
                $mypid = getmypid();
 
                // Quit when in maintenance
-               if (Config::get('system', 'maintenance', false, true)) {
-                       Logger::log("Maintenance mode - quit process ".$mypid, Logger::DEBUG);
+               if (DI::config()->get('system', 'maintenance', false, true)) {
+                       Logger::info("Maintenance mode - quit process", ['pid' => $mypid]);
                        return false;
                }
 
                // Constantly check the number of parallel database processes
-               if ($a->isMaxProcessesReached()) {
-                       Logger::log("Max processes reached for process ".$mypid, Logger::DEBUG);
+               if (DI::process()->isMaxProcessesReached()) {
+                       Logger::info("Max processes reached for process", ['pid' => $mypid]);
                        return false;
                }
 
                // Constantly check the number of available database connections to let the frontend be accessible at any time
                if (self::maxConnectionsReached()) {
-                       Logger::log("Max connection reached for process ".$mypid, Logger::DEBUG);
+                       Logger::info("Max connection reached for process", ['pid' => $mypid]);
                        return false;
                }
 
                $argv = json_decode($queue["parameter"], true);
+               if (empty($argv)) {
+                       Logger::error('Parameter is empty', ['queue' => $queue]);
+                       return false;
+               }
 
                // Check for existance and validity of the include file
                $include = $argv[0];
@@ -277,8 +316,6 @@ class Worker
                        $age = (time() - self::$last_update) / 60;
                        self::$last_update = time();
 
-                       Logger::alert('last_update', ['age' => $age, 'last_update' => self::$last_update]);
-
                        if ($age > 1) {
                                $stamp = (float)microtime(true);
                                DBA::update('workerqueue', ['executed' => DateTimeFormat::utcNow()], ['pid' => $mypid, 'done' => false]);
@@ -293,7 +330,7 @@ class Worker
                        $stamp = (float)microtime(true);
                        $condition = ["`id` = ? AND `next_try` < ?", $queue['id'], DateTimeFormat::utcNow()];
                        if (DBA::update('workerqueue', ['done' => true], $condition)) {
-                               Config::set('system', 'last_worker_execution', DateTimeFormat::utcNow());
+                               DI::config()->set('system', 'last_worker_execution', DateTimeFormat::utcNow());
                        }
                        self::$db_duration = (microtime(true) - $stamp);
                        self::$db_duration_write += (microtime(true) - $stamp);
@@ -339,7 +376,7 @@ class Worker
 
                        $stamp = (float)microtime(true);
                        if (DBA::update('workerqueue', ['done' => true], ['id' => $queue["id"]])) {
-                               Config::set('system', 'last_worker_execution', DateTimeFormat::utcNow());
+                               DI::config()->set('system', 'last_worker_execution', DateTimeFormat::utcNow());
                        }
                        self::$db_duration = (microtime(true) - $stamp);
                        self::$db_duration_write += (microtime(true) - $stamp);
@@ -355,7 +392,7 @@ class Worker
        }
 
        /**
-        * @brief Execute a function from the queue
+        * Execute a function from the queue
         *
         * @param array   $queue       Workerqueue entry
         * @param string  $funcname    name of the function
@@ -366,28 +403,18 @@ class Worker
         */
        private static function execFunction($queue, $funcname, $argv, $method_call)
        {
-               $a = \get_app();
-
-               $mypid = getmypid();
-
-               $argc = count($argv);
+               $a = DI::app();
 
-               // Currently deactivated, since the new logger doesn't support this
-               //$new_process_id = System::processID("wrk");
-               $new_process_id = '';
+               Logger::enableWorker($funcname);
 
-               Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." ".$queue["parameter"]." - Process PID: ".$new_process_id);
+               Logger::info("Process start.", ['priority' => $queue["priority"], 'id' => $queue["id"]]);
 
                $stamp = (float)microtime(true);
 
                // We use the callstack here to analyze the performance of executed worker entries.
                // For this reason the variables have to be initialized.
-               $a->getProfiler()->reset();
+               DI::profiler()->reset();
 
-               // For better logging create a new process id for every worker call
-               // But preserve the old one for the worker
-               $old_process_id = $a->process_id;
-               $a->process_id = $new_process_id;
                $a->queue = $queue;
 
                $up_duration = microtime(true) - self::$up_start;
@@ -395,13 +422,15 @@ class Worker
                // Reset global data to avoid interferences
                unset($_SESSION);
 
+               // Set the workerLogger as new default logger
                if ($method_call) {
                        call_user_func_array(sprintf('Friendica\Worker\%s::execute', $funcname), $argv);
                } else {
-                       $funcname($argv, $argc);
+                       $funcname($argv, count($argv));
                }
 
-               $a->process_id = $old_process_id;
+               Logger::disableWorker();
+
                unset($a->queue);
 
                $duration = (microtime(true) - $stamp);
@@ -411,16 +440,16 @@ class Worker
                 * The execution time is the productive time.
                 * By changing parameters like the maximum number of workers we can check the effectivness.
                */
-               Logger::log(
-                       'DB: '.number_format(self::$db_duration - (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
-               );
+               $dbtotal = round(self::$db_duration, 2);
+               $dbread  = round(self::$db_duration - (self::$db_duration_count + self::$db_duration_write + self::$db_duration_stat), 2);
+               $dbcount = round(self::$db_duration_count, 2);
+               $dbstat  = round(self::$db_duration_stat, 2);
+               $dbwrite = round(self::$db_duration_write, 2);
+               $dblock  = round(self::$lock_duration, 2);
+               $rest    = round(max(0, $up_duration - (self::$db_duration + self::$lock_duration)), 2);
+               $exec    = round($duration, 2);
+
+               Logger::info('Performance:', ['state' => self::$state, 'count' => $dbcount, 'stat' => $dbstat, 'write' => $dbwrite, 'lock' => $dblock, 'total' => $dbtotal, 'rest' => $rest, 'exec' => $exec]);
 
                self::$up_start = microtime(true);
                self::$db_duration = 0;
@@ -430,29 +459,29 @@ class Worker
                self::$lock_duration = 0;
 
                if ($duration > 3600) {
-                       Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 1 hour (".round($duration/60, 3).")", Logger::DEBUG);
+                       Logger::info('Longer than 1 hour.', ['priority' => $queue["priority"], 'id' => $queue["id"], 'duration' => round($duration/60, 3)]);
                } elseif ($duration > 600) {
-                       Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 10 minutes (".round($duration/60, 3).")", Logger::DEBUG);
+                       Logger::info('Longer than 10 minutes.', ['priority' => $queue["priority"], 'id' => $queue["id"], 'duration' => round($duration/60, 3)]);
                } elseif ($duration > 300) {
-                       Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 5 minutes (".round($duration/60, 3).")", Logger::DEBUG);
+                       Logger::info('Longer than 5 minutes.', ['priority' => $queue["priority"], 'id' => $queue["id"], 'duration' => round($duration/60, 3)]);
                } elseif ($duration > 120) {
-                       Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 2 minutes (".round($duration/60, 3).")", Logger::DEBUG);
+                       Logger::info('Longer than 2 minutes.', ['priority' => $queue["priority"], 'id' => $queue["id"], 'duration' => round($duration/60, 3)]);
                }
 
-               Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - done in ".number_format($duration, 4)." seconds. Process PID: ".$new_process_id);
+               Logger::info('Process done.', ['priority' => $queue["priority"], 'id' => $queue["id"], 'duration' => round($duration, 3)]);
 
-               $a->getProfiler()->saveLog("ID " . $queue["id"] . ": " . $funcname);
+               DI::profiler()->saveLog(DI::logger(), "ID " . $queue["id"] . ": " . $funcname);
 
-               $cooldown = Config::get("system", "worker_cooldown", 0);
+               $cooldown = DI::config()->get("system", "worker_cooldown", 0);
 
                if ($cooldown > 0) {
-                       Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - in cooldown for ".$cooldown." seconds");
+                       Logger::info('Cooldown.', ['priority' => $queue["priority"], 'id' => $queue["id"], 'cooldown' => $cooldown]);
                        sleep($cooldown);
                }
        }
 
        /**
-        * @brief Checks if the number of database connections has reached a critical limit.
+        * Checks if the number of database connections has reached a critical limit.
         *
         * @return bool Are more than 3/4 of the maximum connections used?
         * @throws \Friendica\Network\HTTPException\InternalServerErrorException
@@ -460,10 +489,10 @@ class Worker
        private static function maxConnectionsReached()
        {
                // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
-               $max = Config::get("system", "max_connections");
+               $max = DI::config()->get("system", "max_connections");
 
                // Fetch the percentage level where the worker will get active
-               $maxlevel = Config::get("system", "max_connections_level", 75);
+               $maxlevel = DI::config()->get("system", "max_connections_level", 75);
 
                if ($max == 0) {
                        // the maximum number of possible user connections can be a system variable
@@ -495,7 +524,7 @@ class Worker
                        $used = DBA::numRows($r);
                        DBA::close($r);
 
-                       Logger::log("Connection usage (user values): ".$used."/".$max, Logger::DEBUG);
+                       Logger::info("Connection usage (user values)", ['usage' => $used, 'max' => $max]);
 
                        $level = ($used / $max) * 100;
 
@@ -523,7 +552,7 @@ class Worker
                if ($used == 0) {
                        return false;
                }
-               Logger::log("Connection usage (system values): ".$used."/".$max, Logger::DEBUG);
+               Logger::info("Connection usage (system values)", ['used' => $used, 'max' => $max]);
 
                $level = $used / $max * 100;
 
@@ -535,7 +564,8 @@ class Worker
        }
 
        /**
-        * @brief fix the queue entry if the worker process died
+        * fix the queue entry if the worker process died
+        *
         * @return void
         * @throws \Exception
         */
@@ -572,6 +602,10 @@ class Worker
                                $max_duration = $max_duration_defaults[$entry["priority"]];
 
                                $argv = json_decode($entry["parameter"], true);
+                               if (empty($argv)) {
+                                       return;
+                               }
+
                                $argv[0] = basename($argv[0]);
 
                                // How long is the process already running?
@@ -600,24 +634,22 @@ class Worker
                                        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);
+                                       Logger::info('Process runtime is okay', ['pid' => $entry["pid"], 'duration' => $duration, 'max' => $max_duration, 'command' => substr(json_encode($argv), 0, 50)]);
                                }
                        }
                }
+               DBA::close($entries);
        }
 
        /**
-        * @brief Checks if the number of active workers exceeds the given limits
-        *
-        * @param integer $entries Total number of queue entries
-        * @param integer $deferred Number of deferred queue entries
+        * Checks if the number of active workers exceeds the given limits
         *
         * @return bool Are there too much workers running?
         * @throws \Friendica\Network\HTTPException\InternalServerErrorException
         */
-       public static function tooMuchWorkers($entries = 0, $deferred = 0)
+       private static function tooMuchWorkers()
        {
-               $queues = Config::get("system", "worker_queues", 4);
+               $queues = DI::config()->get("system", "worker_queues", 10);
 
                $maxqueues = $queues;
 
@@ -626,21 +658,21 @@ class Worker
                // Decrease the number of workers at higher load
                $load = System::currentLoad();
                if ($load) {
-                       $maxsysload = intval(Config::get("system", "maxloadavg", 50));
+                       $maxsysload = intval(DI::config()->get("system", "maxloadavg", 20));
 
                        /* Default exponent 3 causes queues to rapidly decrease as load increases.
                         * If you have 20 max queues at idle, then you get only 5 queues at 37.1% of $maxsysload.
                         * For some environments, this rapid decrease is not needed.
                         * With exponent 1, you could have 20 max queues at idle and 13 at 37% of $maxsysload.
                         */
-                       $exponent = intval(Config::get('system', 'worker_load_exponent', 3));
+                       $exponent = intval(DI::config()->get('system', 'worker_load_exponent', 3));
                        $slope = pow(max(0, $maxsysload - $load) / $maxsysload, $exponent);
                        $queues = intval(ceil($slope * $maxqueues));
 
                        $processlist = '';
 
-                       if (Config::get('system', 'worker_jpm')) {
-                               $intervals = explode(',', Config::get('system', 'worker_jpm_range'));
+                       if (DI::config()->get('system', 'worker_jpm')) {
+                               $intervals = explode(',', DI::config()->get('system', 'worker_jpm_range'));
                                $jobs_per_minute = [];
                                foreach ($intervals as $interval) {
                                        if ($interval == 0) {
@@ -666,23 +698,18 @@ class Worker
 
                        $idle_workers = $active;
 
-                       if (empty($deferred) && empty($entries)) {
-                               $deferred = self::deferredEntries();
-                               $entries = max(self::totalEntries() - $deferred, 0);
-                       }
-
-                       $waiting_processes = max(0, $entries - $deferred);
+                       $deferred = self::deferredEntries();
 
-                       if (Config::get('system', 'worker_debug')) {
+                       if (DI::config()->get('system', 'worker_debug')) {
                                $waiting_processes = 0;
                                // Now adding all processes with workerqueue 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());
+                               $jobs = DBA::p("SELECT COUNT(*) AS `entries`, `priority` FROM `workerqueue` WHERE NOT `done` GROUP BY `priority`");
                                self::$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"]);
+                                       $processes = DBA::p("SELECT COUNT(*) AS `running` FROM `workerqueue-view` WHERE `priority` = ?", $entry["priority"]);
                                        self::$db_duration += (microtime(true) - $stamp);
                                        self::$db_duration_stat += (microtime(true) - $stamp);
                                        if ($process = DBA::fetch($processes)) {
@@ -694,9 +721,11 @@ class Worker
                                }
                                DBA::close($jobs);
                        } else {
+                               $waiting_processes =  self::totalEntries();
                                $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`");
+                               $jobs = DBA::p("SELECT COUNT(*) AS `running`, `priority` FROM `workerqueue-view` GROUP BY `priority` ORDER BY `priority`");
                                self::$db_duration += (microtime(true) - $stamp);
+                               self::$db_duration_stat += (microtime(true) - $stamp);
 
                                while ($entry = DBA::fetch($jobs)) {
                                        $idle_workers -= $entry["running"];
@@ -705,26 +734,28 @@ class Worker
                                DBA::close($jobs);
                        }
 
+                       $waiting_processes -= $deferred;
+
                        $listitem[0] = "0:" . max(0, $idle_workers);
 
                        $processlist .= ' ('.implode(', ', $listitem).')';
 
-                       if (Config::get("system", "worker_fastlane", false) && ($queues > 0) && self::entriesExists() && ($active >= $queues)) {
+                       if (DI::config()->get("system", "worker_fastlane", false) && ($queues > 0) && ($active >= $queues) && self::entriesExists()) {
                                $top_priority = self::highestPriority();
                                $high_running = self::processWithPriorityActive($top_priority);
 
                                if (!$high_running && ($top_priority > PRIORITY_UNDEFINED) && ($top_priority < PRIORITY_NEGLIGIBLE)) {
-                                       Logger::log("There are jobs with priority ".$top_priority." waiting but none is executed. Open a fastlane.", Logger::DEBUG);
+                                       Logger::info("Jobs with a higher priority are waiting but none is executed. Open a fastlane.", ['priority' => $top_priority]);
                                        $queues = $active + 1;
                                }
                        }
 
-                       Logger::log("Load: " . $load ."/" . $maxsysload . " - processes: " . $deferred . "/" . $active . "/" . $waiting_processes . $processlist . " - maximum: " . $queues . "/" . $maxqueues, Logger::DEBUG);
+                       Logger::notice("Load: " . $load ."/" . $maxsysload . " - processes: " . $deferred . "/" . $active . "/" . $waiting_processes . $processlist . " - maximum: " . $queues . "/" . $maxqueues);
 
                        // Are there fewer workers running as possible? Then fork a new one.
-                       if (!Config::get("system", "worker_dont_fork", false) && ($queues > ($active + 1)) && ($entries > 1)) {
-                               Logger::log("Active workers: ".$active."/".$queues." Fork a new worker.", Logger::DEBUG);
-                               if (Config::get('system', 'worker_daemon_mode', false)) {
+                       if (!DI::config()->get("system", "worker_dont_fork", false) && ($queues > ($active + 1)) && self::entriesExists()) {
+                               Logger::info("There are fewer workers as possible, fork a new worker.", ['active' => $active, 'queues' => $queues]);
+                               if (DI::config()->get('system', 'worker_daemon_mode', false)) {
                                        self::IPCSetJobState(true);
                                } else {
                                        self::spawnWorker();
@@ -733,7 +764,7 @@ class Worker
                }
 
                // if there are too much worker, we don't spawn a new one.
-               if (Config::get('system', 'worker_daemon_mode', false) && ($active > $queues)) {
+               if (DI::config()->get('system', 'worker_daemon_mode', false) && ($active > $queues)) {
                        self::IPCSetJobState(false);
                }
 
@@ -741,7 +772,7 @@ class Worker
        }
 
        /**
-        * @brief Returns the number of active worker processes
+        * Returns the number of active worker processes
         *
         * @return integer Number of active worker processes
         * @throws \Exception
@@ -755,222 +786,196 @@ class Worker
        }
 
        /**
-        * @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.
+        * Returns waiting jobs for the current process id
         *
-        * @param string $highest_priority Returns the currently highest priority
-        * @return bool We let pass a slower process than $highest_priority
+        * @return array waiting workerqueue jobs
         * @throws \Exception
         */
-       private static function passingSlow(&$highest_priority)
+       private static function getWaitingJobForPID()
        {
-               $highest_priority = 0;
-
                $stamp = (float)microtime(true);
-               $r = DBA::p(
-                       "SELECT `priority`
-                               FROM `process`
-                               INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done`"
-               );
+               $r = DBA::select('workerqueue', [], ['pid' => getmypid(), 'done' => false]);
                self::$db_duration += (microtime(true) - $stamp);
-
-               // No active processes at all? Fine
-               if (!DBA::isResult($r)) {
-                       return false;
-               }
-               $priorities = [];
-               while ($line = DBA::fetch($r)) {
-                       $priorities[] = $line["priority"];
+               if (DBA::isResult($r)) {
+                       return DBA::toArray($r);
                }
                DBA::close($r);
 
-               // Should not happen
-               if (count($priorities) == 0) {
-                       return false;
-               }
-               $highest_priority = min($priorities);
+               return false;
+       }
 
-               // The highest process is already the slowest one?
-               // Then we quit
-               if ($highest_priority == PRIORITY_NEGLIGIBLE) {
-                       return false;
+       /**
+        * Returns the next jobs that should be executed
+        *
+        * @return array array with next jobs
+        * @throws \Exception
+        */
+       private static function nextProcess()
+       {
+               $priority = self::nextPriority();
+               if (empty($priority)) {
+                       Logger::info('No tasks found');
+                       return [];
                }
-               $high = 0;
-               foreach ($priorities as $priority) {
-                       if ($priority == $highest_priority) {
-                               ++$high;
+
+               $limit = DI::config()->get('system', 'worker_fetch_limit', 1);
+
+               $ids = [];
+               $stamp = (float)microtime(true);
+               $condition = ["`priority` = ? AND `pid` = 0 AND NOT `done` AND `next_try` < ?", $priority, DateTimeFormat::utcNow()];
+               $tasks = DBA::select('workerqueue', ['id', 'parameter'], $condition, ['limit' => $limit, 'order' => ['created']]);
+               self::$db_duration += (microtime(true) - $stamp);
+               while ($task = DBA::fetch($tasks)) {
+                       $ids[] = $task['id'];
+                       // Only continue that loop while we are storing commands that can be processed quickly
+                       $command = json_decode($task['parameter'])[0];
+                       if (!in_array($command, self::FAST_COMMANDS)) {
+                               break;
                        }
                }
-               Logger::log("Highest priority: ".$highest_priority." Total processes: ".count($priorities)." Count high priority processes: ".$high, Logger::DEBUG);
-               $passing_slow = (($high/count($priorities)) > (2/3));
+               DBA::close($tasks);
 
-               if ($passing_slow) {
-                       Logger::log("Passing slower processes than priority ".$highest_priority, Logger::DEBUG);
-               }
-               return $passing_slow;
+               Logger::info('Found:', ['priority' => $priority, 'id' => $ids]);
+               return $ids;
        }
 
        /**
-        * @brief Find and claim the next worker process for us
+        * Returns the priority of the next workerqueue job
         *
-        * @param boolean $passing_slow Returns if we had passed low priority processes
-        * @param integer $entries Total number of queue entries
-        * @param integer $deferred Number of deferred queue entries
-        * @return boolean Have we found something?
-        * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+        * @return string priority
+        * @throws \Exception
         */
-       private static function findWorkerProcesses(&$passing_slow, $entries, $deferred)
+       private static function nextPriority()
        {
-               $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?
+               $waiting = [];
+               $priorities = [PRIORITY_CRITICAL, PRIORITY_HIGH, PRIORITY_MEDIUM, PRIORITY_LOW, PRIORITY_NEGLIGIBLE];
+               foreach ($priorities as $priority) {
                        $stamp = (float)microtime(true);
-                       $result = DBA::select(
-                               'workerqueue',
-                               ['id'],
-                               ["`pid` = 0 AND `priority` < ? AND NOT `done` AND `next_try` < ?",
-                               $highest_priority, DateTimeFormat::utcNow()],
-                               ['limit' => 1, 'order' => ['priority', 'created']]
-                       );
+                       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);
+               }
 
-                       while ($id = DBA::fetch($result)) {
-                               $ids[] = $id["id"];
-                       }
-                       DBA::close($result);
+               if (!empty($waiting[PRIORITY_CRITICAL])) {
+                       return PRIORITY_CRITICAL;
+               }
 
-                       $found = (count($ids) > 0);
+               $running = [];
+               $running_total = 0;
+               $stamp = (float)microtime(true);
+               $processes = DBA::p("SELECT COUNT(DISTINCT(`pid`)) AS `running`, `priority` FROM `workerqueue-view` GROUP BY `priority`");
+               self::$db_duration += (microtime(true) - $stamp);
+               while ($process = DBA::fetch($processes)) {
+                       $running[$process['priority']] = $process['running'];
+                       $running_total += $process['running'];
+               }
+               DBA::close($processes);
 
-                       if (!$found) {
-                               // Give slower processes some processing time
-                               $stamp = (float)microtime(true);
-                               $result = DBA::select(
-                                       'workerqueue',
-                                       ['id'],
-                                       ["`pid` = 0 AND `priority` > ? AND NOT `done` AND `next_try` < ?",
-                                       $highest_priority, DateTimeFormat::utcNow()],
-                                       ['limit' => 1, 'order' => ['priority', 'created']]
-                               );
-                               self::$db_duration += (microtime(true) - $stamp);
+               foreach ($priorities as $priority) {
+                       if (!empty($waiting[$priority]) && empty($running[$priority])) {
+                               Logger::info('No running worker found with priority {priority} - assigning it.', ['priority' => $priority]);
+                               return $priority;
+                       }
+               }
 
-                               while ($id = DBA::fetch($result)) {
-                                       $ids[] = $id["id"];
-                               }
-                               DBA::close($result);
+               $active = max(self::activeWorkers(), $running_total);
+               $priorities = max(count($waiting), count($running));
+               $exponent = 2;
 
-                               $found = (count($ids) > 0);
-                               $passing_slow = $found;
-                       }
+               $total = 0;
+               for ($i = 1; $i <= $priorities; ++$i) {
+                       $total += pow($i, $exponent);
                }
 
-               // At first try to fetch a bunch of high or medium tasks
-               if (!$found && ($limit > 1)) {
-                       $stamp = (float)microtime(true);
-                       $result = DBA::select(
-                               'workerqueue',
-                               ['id'],
-                               ["`pid` = 0 AND NOT `done` AND `priority` <= ? AND `next_try` < ? AND `retrial` = 0",
-                               PRIORITY_MEDIUM, DateTimeFormat::utcNow()],
-                               ['limit' => $limit, 'order' => ['created']]
-                       );
-                       self::$db_duration += (microtime(true) - $stamp);
+               $limit = [];
+               for ($i = 1; $i <= $priorities; ++$i) {
+                       $limit[$priorities - $i] = max(1, round($active * (pow($i, $exponent) / $total)));
+               }
 
-                       while ($id = DBA::fetch($result)) {
-                               $ids[] = $id["id"];
+               $i = 0;
+               foreach ($running as $priority => $workers) {
+                       if ($workers < $limit[$i++]) {
+                               Logger::info('Priority {priority} has got {workers} workers out of a limit of {limit}', ['priority' => $priority, 'workers' => $workers, 'limit' => $limit[$i - 1]]);
+                               return $priority;
                        }
-                       DBA::close($result);
+               }
 
-                       $found = (count($ids) > 0);
+               if (!empty($waiting)) {
+                       $priority = array_keys($waiting)[0];
+                       Logger::info('No underassigned priority found, now taking the highest priority.', ['priority' => $priority]);
+                       return $priority;
                }
 
-               // If there is no result (or we shouldn't pass lower processes) we check without priority limit
-               if (!$found) {
+               return false;
+       }
+
+       /**
+        * Find and claim the next worker process for us
+        *
+        * @return boolean Have we found something?
+        * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+        */
+       private static function findWorkerProcesses()
+       {
+               $mypid = getmypid();
+
+               $ids = self::nextProcess();
+
+               // If there is no result we check without priority limit
+               if (empty($ids)) {
+                       $limit = DI::config()->get('system', 'worker_fetch_limit', 1);
+
                        $stamp = (float)microtime(true);
-                       $result = DBA::select(
-                               'workerqueue',
-                               ['id'],
-                               ["`pid` = 0 AND NOT `done` AND `next_try` < ?",
-                               DateTimeFormat::utcNow()],
-                               ['limit' => 1, 'order' => ['priority', 'created']]
-                       );
+                       $condition = ["`pid` = 0 AND NOT `done` AND `next_try` < ?", DateTimeFormat::utcNow()];
+                       $tasks = DBA::select('workerqueue', ['id', 'parameter'], $condition, ['limit' => $limit, 'order' => ['priority', 'created']]);
                        self::$db_duration += (microtime(true) - $stamp);
 
-                       while ($id = DBA::fetch($result)) {
-                               $ids[] = $id["id"];
+                       while ($task = DBA::fetch($tasks)) {
+                               $ids[] = $task['id'];
+                               // Only continue that loop while we are storing commands that can be processed quickly
+                               $command = json_decode($task['parameter'])[0];
+                               if (!in_array($command, self::FAST_COMMANDS)) {
+                                       break;
+                               }
                        }
-                       DBA::close($result);
-
-                       $found = (count($ids) > 0);
+                       DBA::close($tasks);
                }
 
-               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);
+                       $condition = ['id' => $ids, 'done' => false, 'pid' => 0];
+                       DBA::update('workerqueue', ['executed' => DateTimeFormat::utcNow(), 'pid' => $mypid], $condition);
                        self::$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
-        * @param integer $entries Returns total number of queue entries
-        * @param integer $deferred Returns number of deferred queue entries
+        * Returns the next worker process
         *
-        * @return string SQL statement
+        * @return array worker processes
         * @throws \Friendica\Network\HTTPException\InternalServerErrorException
         */
-       public static function workerProcess(&$passing_slow, &$entries, &$deferred)
+       public static function workerProcess()
        {
                // There can already be jobs for us in the queue.
-               $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);
+               $waiting = self::getWaitingJobForPID();
+               if (!empty($waiting)) {
+                       return $waiting;
                }
-               DBA::close($r);
-
-               // Counting the rows outside the lock reduces the lock time
-               $entries = self::totalEntries();
-               $deferred = self::deferredEntries();
 
                $stamp = (float)microtime(true);
-               if (!Lock::acquire('worker_process')) {
+               if (!DI::lock()->acquire(self::LOCK_PROCESS)) {
                        return false;
                }
                self::$lock_duration += (microtime(true) - $stamp);
 
-               $found = self::findWorkerProcesses($passing_slow, $entries, $deferred);
+               $found = self::findWorkerProcesses();
 
-               Lock::release('worker_process');
+               DI::lock()->release(self::LOCK_PROCESS);
 
                if ($found) {
                        $stamp = (float)microtime(true);
@@ -982,7 +987,8 @@ class Worker
        }
 
        /**
-        * @brief Removes a workerqueue entry from the current process
+        * Removes a workerqueue entry from the current process
+        *
         * @return void
         * @throws \Exception
         */
@@ -997,28 +1003,30 @@ class Worker
        }
 
        /**
-        * @brief Call the front end worker
+        * Call the front end worker
+        *
         * @return void
         * @throws \Friendica\Network\HTTPException\InternalServerErrorException
         */
        public static function callWorker()
        {
-               if (!Config::get("system", "frontend_worker")) {
+               if (!DI::config()->get("system", "frontend_worker")) {
                        return;
                }
 
-               $url = System::baseUrl()."/worker";
-               Network::fetchUrl($url, false, $redirects, 1);
+               $url = DI::baseUrl() . '/worker';
+               DI::httpRequest()->fetch($url, false, 1);
        }
 
        /**
-        * @brief Call the front end worker if there aren't any active
+        * Call the front end worker if there aren't any active
+        *
         * @return void
         * @throws \Friendica\Network\HTTPException\InternalServerErrorException
         */
        public static function executeIfIdle()
        {
-               if (!Config::get("system", "frontend_worker")) {
+               if (!DI::config()->get("system", "frontend_worker")) {
                        return;
                }
 
@@ -1026,11 +1034,11 @@ class Worker
                if (function_exists("proc_open")) {
                        // When was the last time that we called the worker?
                        // Less than one minute? Then we quit
-                       if ((time() - Config::get("system", "worker_started")) < 60) {
+                       if ((time() - DI::config()->get("system", "worker_started")) < 60) {
                                return;
                        }
 
-                       Config::set("system", "worker_started", time());
+                       DI::config()->set("system", "worker_started", time());
 
                        // Do we have enough running workers? Then we quit here.
                        if (self::tooMuchWorkers()) {
@@ -1043,7 +1051,7 @@ class Worker
 
                        self::runCron();
 
-                       Logger::log('Call worker', Logger::DEBUG);
+                       Logger::info('Call worker');
                        self::spawnWorker();
                        return;
                }
@@ -1063,13 +1071,14 @@ class Worker
        }
 
        /**
-        * @brief Removes long running worker processes
+        * Removes long running worker processes
+        *
         * @return void
         * @throws \Friendica\Network\HTTPException\InternalServerErrorException
         */
        public static function clearProcesses()
        {
-               $timeout = Config::get("system", "frontend_worker_timeout", 10);
+               $timeout = DI::config()->get("system", "frontend_worker_timeout", 10);
 
                /// @todo We should clean up the corresponding workerqueue entries as well
                $stamp = (float)microtime(true);
@@ -1081,13 +1090,14 @@ class Worker
        }
 
        /**
-        * @brief Runs the cron processes
+        * Runs the cron processes
+        *
         * @return void
         * @throws \Friendica\Network\HTTPException\InternalServerErrorException
         */
        private static function runCron()
        {
-               Logger::log('Add cron entries', Logger::DEBUG);
+               Logger::info('Add cron entries');
 
                // Check for spooled items
                self::add(['priority' => PRIORITY_HIGH, 'force_priority' => true], 'SpoolPost');
@@ -1100,7 +1110,8 @@ class Worker
        }
 
        /**
-        * @brief Spawns a new worker
+        * Spawns a new worker
+        *
         * @param bool $do_cron
         * @return void
         * @throws \Friendica\Network\HTTPException\InternalServerErrorException
@@ -1111,24 +1122,26 @@ class Worker
 
                $args = ['no_cron' => !$do_cron];
 
-               get_app()->proc_run($command, $args);
+               $a = DI::app();
+               $process = new Core\Process(DI::logger(), DI::mode(), DI::config(), $a->getBasePath());
+               $process->run($command, $args);
 
                // after spawning we have to remove the flag.
-               if (Config::get('system', 'worker_daemon_mode', false)) {
+               if (DI::config()->get('system', 'worker_daemon_mode', false)) {
                        self::IPCSetJobState(false);
                }
        }
 
        /**
-        * @brief Adds tasks to the worker queue
+        * Adds tasks to the worker queue
         *
         * @param (integer|array) priority or parameter array, strings are deprecated and are ignored
         *
         * next args are passed as $cmd command line
-        * or: Worker::add(PRIORITY_HIGH, "Notifier", "drop", $drop_id);
+        * or: Worker::add(PRIORITY_HIGH, "Notifier", Delivery::DELETION, $drop_id);
         * or: Worker::add(array('priority' => PRIORITY_HIGH, 'dont_fork' => true), "CreateShadowEntry", $post_id);
         *
-        * @return boolean "false" if proc_run couldn't be executed
+        * @return boolean "false" if worker queue entry already existed or there had been an error
         * @throws \Friendica\Network\HTTPException\InternalServerErrorException
         * @note $cmd and string args are surrounded with ""
         *
@@ -1152,7 +1165,8 @@ class Worker
                }
 
                $priority = PRIORITY_MEDIUM;
-               $dont_fork = Config::get("system", "worker_dont_fork", false);
+               // Don't fork from frontend tasks by default
+               $dont_fork = DI::config()->get("system", "worker_dont_fork", false) || !DI::mode()->isBackend();
                $created = DateTimeFormat::utcNow();
                $force_priority = false;
 
@@ -1177,6 +1191,7 @@ class Worker
 
                $parameters = json_encode($args);
                $found = DBA::exists('workerqueue', ['parameter' => $parameters, 'done' => false]);
+               $added = false;
 
                // Quit if there was a database error - a precaution for the update process to 3.5.3
                if (DBA::errorNo() != 0) {
@@ -1184,86 +1199,121 @@ class Worker
                }
 
                if (!$found) {
-                       DBA::insert('workerqueue', ['parameter' => $parameters, 'created' => $created, 'priority' => $priority]);
+                       $added = DBA::insert('workerqueue', ['parameter' => $parameters, 'created' => $created, 'priority' => $priority]);
+                       if (!$added) {
+                               return false;
+                       }
                } elseif ($force_priority) {
                        DBA::update('workerqueue', ['priority' => $priority], ['parameter' => $parameters, 'done' => false, 'pid' => 0]);
                }
 
                // Should we quit and wait for the worker to be called as a cronjob?
                if ($dont_fork) {
-                       return true;
+                       return $added;
                }
 
                // If there is a lock then we don't have to check for too much worker
-               if (!Lock::acquire('worker', 0)) {
-                       return true;
+               if (!DI::lock()->acquire(self::LOCK_WORKER, 0)) {
+                       return $added;
                }
 
                // If there are already enough workers running, don't fork another one
                $quit = self::tooMuchWorkers();
-               Lock::release('worker');
+               DI::lock()->release(self::LOCK_WORKER);
 
                if ($quit) {
-                       return true;
+                       return $added;
                }
 
                // We tell the daemon that a new job entry exists
-               if (Config::get('system', 'worker_daemon_mode', false)) {
+               if (DI::config()->get('system', 'worker_daemon_mode', false)) {
                        // We don't have to set the IPC flag - this is done in "tooMuchWorkers"
-                       return true;
+                       return $added;
                }
 
                // Now call the worker to execute the jobs that we just added to the queue
                self::spawnWorker();
 
-               return true;
+               return $added;
+       }
+
+       /**
+        * Returns the next retrial level for worker jobs.
+        * This function will skip levels when jobs are older.
+        *
+        * @param array $queue Worker queue entry
+        * @param integer $max_level maximum retrial level
+        * @return integer the next retrial level value
+        */
+       private static function getNextRetrial($queue, $max_level)
+       {
+               $created = strtotime($queue['created']);
+               $retrial_time = time() - $created;
+
+               $new_retrial = $queue['retrial'] + 1;
+               $total = 0;
+               for ($retrial = 0; $retrial <= $max_level + 1; ++$retrial) {
+                       $delay = (($retrial + 3) ** 4) + (rand(1, 30) * ($retrial + 1));
+                       $total += $delay;
+                       if (($total < $retrial_time) && ($retrial > $queue['retrial'])) {
+                               $new_retrial = $retrial;
+                       }
+               }
+               Logger::info('New retrial for task', ['id' => $queue['id'], 'created' => $queue['created'], 'old' => $queue['retrial'], 'new' => $new_retrial]);
+               return $new_retrial;
        }
 
        /**
         * Defers the current worker entry
+        *
+        * @return boolean had the entry been deferred?
         */
        public static function defer()
        {
-               if (empty(BaseObject::getApp()->queue)) {
-                       return;
+               if (empty(DI::app()->queue)) {
+                       return false;
                }
 
-               $queue = BaseObject::getApp()->queue;
+               $queue = DI::app()->queue;
 
                $retrial = $queue['retrial'];
                $id = $queue['id'];
                $priority = $queue['priority'];
 
-               if ($retrial > 14) {
-                       Logger::log('Id ' . $id . ' had been tried 14 times. We stop now.', Logger::DEBUG);
-                       return;
+               $max_level = DI::config()->get('system', 'worker_defer_limit');
+
+               $new_retrial = self::getNextRetrial($queue, $max_level);
+
+               if ($new_retrial > $max_level) {
+                       Logger::info('The task exceeded the maximum retry count', ['id' => $id, 'created' => $queue['created'], 'old_prio' => $queue['priority'], 'old_retrial' => $queue['retrial'], 'max_level' => $max_level, 'retrial' => $new_retrial]);
+                       return false;
                }
 
                // Calculate the delay until the next trial
-               $delay = (($retrial + 3) ** 4) + (rand(1, 30) * ($retrial + 1));
+               $delay = (($new_retrial + 2) ** 4) + (rand(1, 30) * ($new_retrial));
                $next = DateTimeFormat::utc('now + ' . $delay . ' seconds');
 
-               if (($priority < PRIORITY_MEDIUM) && ($retrial > 2)) {
+               if (($priority < PRIORITY_MEDIUM) && ($new_retrial > 3)) {
                        $priority = PRIORITY_MEDIUM;
-               } elseif (($priority < PRIORITY_LOW) && ($retrial > 5)) {
+               } elseif (($priority < PRIORITY_LOW) && ($new_retrial > 6)) {
                        $priority = PRIORITY_LOW;
-               } elseif (($priority < PRIORITY_NEGLIGIBLE) && ($retrial > 7)) {
+               } elseif (($priority < PRIORITY_NEGLIGIBLE) && ($new_retrial > 8)) {
                        $priority = PRIORITY_NEGLIGIBLE;
                }
 
-               Logger::log('Defer execution ' . $retrial . ' of id ' . $id . ' to ' . $next . ' - priority old/new: ' . $queue['priority'] . '/' . $priority, Logger::DEBUG);
+               Logger::info('Deferred task', ['id' => $id, 'retrial' => $new_retrial, 'created' => $queue['created'], 'next_execution' => $next, 'old_prio' => $queue['priority'], 'new_prio' => $priority]);
 
                $stamp = (float)microtime(true);
-               $fields = ['retrial' => $retrial + 1, 'next_try' => $next, 'executed' => DBA::NULL_DATETIME, 'pid' => 0, 'priority' => $priority];
+               $fields = ['retrial' => $new_retrial, '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);
+
+               return true;
        }
 
        /**
         * Log active processes into the "process" table
-        *
-        * @brief Log active processes into the "process" table
         */
        public static function startProcess()
        {
@@ -1279,7 +1329,6 @@ class Worker
        /**
         * Remove the active process from the "process" table
         *
-        * @brief Remove the active process from the "process" table
         * @return bool
         * @throws \Exception
         */
@@ -1291,7 +1340,6 @@ class Worker
        /**
         * Set the flag if some job is waiting
         *
-        * @brief Set the flag if some job is waiting
         * @param boolean $jobs Is there a waiting job?
         * @throws \Exception
         */
@@ -1306,7 +1354,6 @@ class Worker
        /**
         * Checks if some worker job waits to be executed
         *
-        * @brief Checks if some worker job waits to be executed
         * @return bool
         * @throws \Exception
         */