src/Core/Worker.php

   1 <?php
   2 /**
   3  * @file src/Core/Worker.php
   4  */
   5 namespace Friendica\Core;
   6
   7 use Friendica\BaseObject;
   8 use Friendica\Database\DBA;
   9 use Friendica\Model\Process;
  10 use Friendica\Util\DateTimeFormat;
  11 use Friendica\Util\Network;
  12
  13 /**
  14  * @file src/Core/Worker.php
  15  *
  16  * @brief Contains the class for the worker background job processing
  17  */
  18
  19 /**
  20  * @brief Worker methods
  21  */
  22 class Worker
  23 {
  24         private static $up_start;
  25         private static $db_duration;
  26         private static $last_update;
  27         private static $lock_duration;
  28
  29         /**
  30          * @brief Processes the tasks that are in the workerqueue table
  31          *
  32          * @param boolean $run_cron Should the cron processes be executed?
  33          * @return void
  34          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
  35          */
  36         public static function processQueue($run_cron = true)
  37         {
  38                 $a = \get_app();
  39
  40                 self::$up_start = microtime(true);
  41
  42                 // At first check the maximum load. We shouldn't continue with a high load
  43                 if ($a->isMaxLoadReached()) {
  44                         Logger::log('Pre check: maximum load reached, quitting.', Logger::DEBUG);
  45                         return;
  46                 }
  47
  48                 // We now start the process. This is done after the load check since this could increase the load.
  49                 self::startProcess();
  50
  51                 // Kill stale processes every 5 minutes
  52                 $last_cleanup = Config::get('system', 'worker_last_cleaned', 0);
  53                 if (time() > ($last_cleanup + 300)) {
  54                         Config::set('system', 'worker_last_cleaned', time());
  55                         self::killStaleWorkers();
  56                 }
  57
  58                 // Count active workers and compare them with a maximum value that depends on the load
  59                 if (self::tooMuchWorkers()) {
  60                         Logger::log('Pre check: Active worker limit reached, quitting.', Logger::DEBUG);
  61                         return;
  62                 }
  63
  64                 // Do we have too few memory?
  65                 if ($a->isMinMemoryReached()) {
  66                         Logger::log('Pre check: Memory limit reached, quitting.', Logger::DEBUG);
  67                         return;
  68                 }
  69
  70                 // Possibly there are too much database connections
  71                 if (self::maxConnectionsReached()) {
  72                         Logger::log('Pre check: maximum connections reached, quitting.', Logger::DEBUG);
  73                         return;
  74                 }
  75
  76                 // Possibly there are too much database processes that block the system
  77                 if ($a->isMaxProcessesReached()) {
  78                         Logger::log('Pre check: maximum processes reached, quitting.', Logger::DEBUG);
  79                         return;
  80                 }
  81
  82                 // Now we start additional cron processes if we should do so
  83                 if ($run_cron) {
  84                         self::runCron();
  85                 }
  86
  87                 $starttime = time();
  88
  89                 // We fetch the next queue entry that is about to be executed
  90                 while ($r = self::workerProcess($passing_slow)) {
  91                         // When we are processing jobs with a lower priority, we don't refetch new jobs
  92                         // Otherwise fast jobs could wait behind slow ones and could be blocked.
  93                         $refetched = $passing_slow;
  94
  95                         foreach ($r as $entry) {
  96                                 // Assure that the priority is an integer value
  97                                 $entry['priority'] = (int)$entry['priority'];
  98
  99                                 // The work will be done
 100                                 if (!self::execute($entry)) {
 101                                         Logger::log('Process execution failed, quitting.', Logger::DEBUG);
 102                                         return;
 103                                 }
 104
 105                                 // If possible we will fetch new jobs for this worker
 106                                 if (!$refetched) {
 107                                         $entries = self::totalEntries();
 108                                         $deferred = self::deferredEntries();
 109                                         if (Lock::acquire('worker_process', 0)) {
 110                                                 $stamp = (float)microtime(true);
 111                                                 $refetched = self::findWorkerProcesses($passing_slow, $entries, $deferred);
 112                                                 self::$db_duration += (microtime(true) - $stamp);
 113                                                 Lock::release('worker_process');
 114                                         }
 115                                 }
 116                         }
 117
 118                         // To avoid the quitting of multiple workers only one worker at a time will execute the check
 119                         if (Lock::acquire('worker', 0)) {
 120                                 $stamp = (float)microtime(true);
 121                                 // Count active workers and compare them with a maximum value that depends on the load
 122                                 if (self::tooMuchWorkers()) {
 123                                         Logger::log('Active worker limit reached, quitting.', Logger::DEBUG);
 124                                         Lock::release('worker');
 125                                         return;
 126                                 }
 127
 128                                 // Check free memory
 129                                 if ($a->isMinMemoryReached()) {
 130                                         Logger::log('Memory limit reached, quitting.', Logger::DEBUG);
 131                                         Lock::release('worker');
 132                                         return;
 133                                 }
 134                                 Lock::release('worker');
 135                                 self::$db_duration += (microtime(true) - $stamp);
 136                         }
 137
 138                         // Quit the worker once every 5 minutes
 139                         if (time() > ($starttime + 300)) {
 140                                 Logger::log('Process lifetime reached, quitting.', Logger::DEBUG);
 141                                 return;
 142                         }
 143                 }
 144
 145                 // Cleaning up. Possibly not needed, but it doesn't harm anything.
 146                 if (Config::get('system', 'worker_daemon_mode', false)) {
 147                         self::IPCSetJobState(false);
 148                 }
 149                 Logger::log("Couldn't select a workerqueue entry, quitting process " . getmypid() . ".", Logger::DEBUG);
 150         }
 151
 152         /**
 153          * @brief Returns the number of deferred entries in the worker queue
 154          *
 155          * @return integer Number of deferred entries in the worker queue
 156          * @throws \Exception
 157          */
 158         private static function deferredEntries()
 159         {
 160                 return DBA::count('workerqueue', ["NOT `done` AND `pid` = 0 AND `next_try` > ?", DateTimeFormat::utcNow()]);
 161         }
 162
 163         /**
 164          * @brief Returns the number of non executed entries in the worker queue
 165          *
 166          * @return integer Number of non executed entries in the worker queue
 167          * @throws \Exception
 168          */
 169         private static function totalEntries()
 170         {
 171                 return DBA::count('workerqueue', ['done' => false, 'pid' => 0]);
 172         }
 173
 174         /**
 175          * @brief Returns the highest priority in the worker queue that isn't executed
 176          *
 177          * @return integer Number of active worker processes
 178          * @throws \Exception
 179          */
 180         private static function highestPriority()
 181         {
 182                 $condition = ["`pid` = 0 AND NOT `done` AND `next_try` < ?", DateTimeFormat::utcNow()];
 183                 $workerqueue = DBA::selectFirst('workerqueue', ['priority'], $condition, ['order' => ['priority']]);
 184                 if (DBA::isResult($workerqueue)) {
 185                         return $workerqueue["priority"];
 186                 } else {
 187                         return 0;
 188                 }
 189         }
 190
 191         /**
 192          * @brief Returns if a process with the given priority is running
 193          *
 194          * @param integer $priority The priority that should be checked
 195          *
 196          * @return integer Is there a process running with that priority?
 197          * @throws \Exception
 198          */
 199         private static function processWithPriorityActive($priority)
 200         {
 201                 $condition = ["`priority` <= ? AND `pid` != 0 AND NOT `done`", $priority];
 202                 return DBA::exists('workerqueue', $condition);
 203         }
 204
 205         /**
 206          * @brief Execute a worker entry
 207          *
 208          * @param array $queue Workerqueue entry
 209          *
 210          * @return boolean "true" if further processing should be stopped
 211          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 212          */
 213         public static function execute($queue)
 214         {
 215                 $a = \get_app();
 216
 217                 $mypid = getmypid();
 218
 219                 // Quit when in maintenance
 220                 if (Config::get('system', 'maintenance', false, true)) {
 221                         Logger::log("Maintenance mode - quit process ".$mypid, Logger::DEBUG);
 222                         return false;
 223                 }
 224
 225                 // Constantly check the number of parallel database processes
 226                 if ($a->isMaxProcessesReached()) {
 227                         Logger::log("Max processes reached for process ".$mypid, Logger::DEBUG);
 228                         return false;
 229                 }
 230
 231                 // Constantly check the number of available database connections to let the frontend be accessible at any time
 232                 if (self::maxConnectionsReached()) {
 233                         Logger::log("Max connection reached for process ".$mypid, Logger::DEBUG);
 234                         return false;
 235                 }
 236
 237                 $argv = json_decode($queue["parameter"], true);
 238
 239                 // Check for existance and validity of the include file
 240                 $include = $argv[0];
 241
 242                 if (method_exists(sprintf('Friendica\Worker\%s', $include), 'execute')) {
 243                         // We constantly update the "executed" date every minute to avoid being killed too soon
 244                         if (!isset(self::$last_update)) {
 245                                 self::$last_update = strtotime($queue["executed"]);
 246                         }
 247
 248                         $age = (time() - self::$last_update) / 60;
 249                         self::$last_update = time();
 250
 251                         if ($age > 1) {
 252                                 $stamp = (float)microtime(true);
 253                                 DBA::update('workerqueue', ['executed' => DateTimeFormat::utcNow()], ['pid' => $mypid, 'done' => false]);
 254                                 self::$db_duration += (microtime(true) - $stamp);
 255                         }
 256
 257                         array_shift($argv);
 258
 259                         self::execFunction($queue, $include, $argv, true);
 260
 261                         $stamp = (float)microtime(true);
 262
 263                         $condition = ["`id` = ? AND `next_try` < ?", $queue['id'], DateTimeFormat::utcNow()];
 264                         if (DBA::update('workerqueue', ['done' => true], $condition)) {
 265                                 Config::set('system', 'last_worker_execution', DateTimeFormat::utcNow());
 266                         }
 267                         self::$db_duration = (microtime(true) - $stamp);
 268
 269                         return true;
 270                 }
 271
 272                 // The script could be provided as full path or only with the function name
 273                 if ($include == basename($include)) {
 274                         $include = "include/".$include.".php";
 275                 }
 276
 277                 if (!validate_include($include)) {
 278                         Logger::log("Include file ".$argv[0]." is not valid!");
 279                         DBA::delete('workerqueue', ['id' => $queue["id"]]);
 280                         return true;
 281                 }
 282
 283                 require_once $include;
 284
 285                 $funcname = str_replace(".php", "", basename($argv[0]))."_run";
 286
 287                 if (function_exists($funcname)) {
 288                         // We constantly update the "executed" date every minute to avoid being killed too soon
 289                         if (!isset(self::$last_update)) {
 290                                 self::$last_update = strtotime($queue["executed"]);
 291                         }
 292
 293                         $age = (time() - self::$last_update) / 60;
 294                         self::$last_update = time();
 295
 296                         if ($age > 1) {
 297                                 $stamp = (float)microtime(true);
 298                                 DBA::update('workerqueue', ['executed' => DateTimeFormat::utcNow()], ['pid' => $mypid, 'done' => false]);
 299                                 self::$db_duration += (microtime(true) - $stamp);
 300                         }
 301
 302                         self::execFunction($queue, $funcname, $argv, false);
 303
 304                         $stamp = (float)microtime(true);
 305                         if (DBA::update('workerqueue', ['done' => true], ['id' => $queue["id"]])) {
 306                                 Config::set('system', 'last_worker_execution', DateTimeFormat::utcNow());
 307                         }
 308                         self::$db_duration = (microtime(true) - $stamp);
 309                 } else {
 310                         Logger::log("Function ".$funcname." does not exist");
 311                         DBA::delete('workerqueue', ['id' => $queue["id"]]);
 312                 }
 313
 314                 return true;
 315         }
 316
 317         /**
 318          * @brief Execute a function from the queue
 319          *
 320          * @param array   $queue       Workerqueue entry
 321          * @param string  $funcname    name of the function
 322          * @param array   $argv        Array of values to be passed to the function
 323          * @param boolean $method_call boolean
 324          * @return void
 325          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 326          */
 327         private static function execFunction($queue, $funcname, $argv, $method_call)
 328         {
 329                 $a = \get_app();
 330
 331                 $mypid = getmypid();
 332
 333                 $argc = count($argv);
 334
 335                 $new_process_id = System::processID("wrk");
 336
 337                 Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." ".$queue["parameter"]." - Process PID: ".$new_process_id);
 338
 339                 $stamp = (float)microtime(true);
 340
 341                 // We use the callstack here to analyze the performance of executed worker entries.
 342                 // For this reason the variables have to be initialized.
 343                 if (Config::get("system", "profiler")) {
 344                         $a->performance["start"] = microtime(true);
 345                         $a->performance["database"] = 0;
 346                         $a->performance["database_write"] = 0;
 347                         $a->performance["cache"] = 0;
 348                         $a->performance["cache_write"] = 0;
 349                         $a->performance["network"] = 0;
 350                         $a->performance["file"] = 0;
 351                         $a->performance["rendering"] = 0;
 352                         $a->performance["parser"] = 0;
 353                         $a->performance["marktime"] = 0;
 354                         $a->performance["markstart"] = microtime(true);
 355                         $a->callstack = [];
 356                 }
 357
 358                 // For better logging create a new process id for every worker call
 359                 // But preserve the old one for the worker
 360                 $old_process_id = $a->process_id;
 361                 $a->process_id = $new_process_id;
 362                 $a->queue = $queue;
 363
 364                 $up_duration = number_format(microtime(true) - self::$up_start, 3);
 365
 366                 // Reset global data to avoid interferences
 367                 unset($_SESSION);
 368
 369                 if ($method_call) {
 370                         call_user_func_array(sprintf('Friendica\Worker\%s::execute', $funcname), $argv);
 371                 } else {
 372                         $funcname($argv, $argc);
 373                 }
 374
 375                 $a->process_id = $old_process_id;
 376                 unset($a->queue);
 377
 378                 $duration = (microtime(true) - $stamp);
 379
 380                 self::$up_start = microtime(true);
 381
 382                 /* With these values we can analyze how effective the worker is.
 383                  * The database and rest time should be low since this is the unproductive time.
 384                  * The execution time is the productive time.
 385                  * By changing parameters like the maximum number of workers we can check the effectivness.
 386                 */
 387                 Logger::log(
 388                         'DB: '.number_format(self::$db_duration, 2).
 389                         ' - Lock: '.number_format(self::$lock_duration, 2).
 390                         ' - Rest: '.number_format($up_duration - self::$db_duration - self::$lock_duration, 2).
 391                         ' - Execution: '.number_format($duration, 2),
 392                         Logger::DEBUG
 393                 );
 394
 395                 self::$lock_duration = 0;
 396
 397                 if ($duration > 3600) {
 398                         Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 1 hour (".round($duration/60, 3).")", Logger::DEBUG);
 399                 } elseif ($duration > 600) {
 400                         Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 10 minutes (".round($duration/60, 3).")", Logger::DEBUG);
 401                 } elseif ($duration > 300) {
 402                         Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 5 minutes (".round($duration/60, 3).")", Logger::DEBUG);
 403                 } elseif ($duration > 120) {
 404                         Logger::log("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 2 minutes (".round($duration/60, 3).")", Logger::DEBUG);
 405                 }
 406
 407                 Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - done in ".$duration." seconds. Process PID: ".$new_process_id);
 408
 409                 // Write down the performance values into the log
 410                 if (Config::get("system", "profiler")) {
 411                         $duration = microtime(true)-$a->performance["start"];
 412
 413                         $o = '';
 414                         if (Config::get("rendertime", "callstack")) {
 415                                 if (isset($a->callstack["database"])) {
 416                                         $o .= "\nDatabase Read:\n";
 417                                         foreach ($a->callstack["database"] as $func => $time) {
 418                                                 $time = round($time, 3);
 419                                                 if ($time > 0) {
 420                                                         $o .= $func.": ".$time."\n";
 421                                                 }
 422                                         }
 423                                 }
 424                                 if (isset($a->callstack["database_write"])) {
 425                                         $o .= "\nDatabase Write:\n";
 426                                         foreach ($a->callstack["database_write"] as $func => $time) {
 427                                                 $time = round($time, 3);
 428                                                 if ($time > 0) {
 429                                                         $o .= $func.": ".$time."\n";
 430                                                 }
 431                                         }
 432                                 }
 433                                 if (isset($a->callstack["dache"])) {
 434                                         $o .= "\nCache Read:\n";
 435                                         foreach ($a->callstack["dache"] as $func => $time) {
 436                                                 $time = round($time, 3);
 437                                                 if ($time > 0) {
 438                                                         $o .= $func.": ".$time."\n";
 439                                                 }
 440                                         }
 441                                 }
 442                                 if (isset($a->callstack["dache_write"])) {
 443                                         $o .= "\nCache Write:\n";
 444                                         foreach ($a->callstack["dache_write"] as $func => $time) {
 445                                                 $time = round($time, 3);
 446                                                 if ($time > 0) {
 447                                                         $o .= $func.": ".$time."\n";
 448                                                 }
 449                                         }
 450                                 }
 451                                 if (isset($a->callstack["network"])) {
 452                                         $o .= "\nNetwork:\n";
 453                                         foreach ($a->callstack["network"] as $func => $time) {
 454                                                 $time = round($time, 3);
 455                                                 if ($time > 0) {
 456                                                         $o .= $func.": ".$time."\n";
 457                                                 }
 458                                         }
 459                                 }
 460                         }
 461
 462                         Logger::log(
 463                                 "ID ".$queue["id"].": ".$funcname.": ".sprintf(
 464                                         "DB: %s/%s, Cache: %s/%s, Net: %s, I/O: %s, Other: %s, Total: %s".$o,
 465                                         number_format($a->performance["database"] - $a->performance["database_write"], 2),
 466                                         number_format($a->performance["database_write"], 2),
 467                                         number_format($a->performance["cache"], 2),
 468                                         number_format($a->performance["cache_write"], 2),
 469                                         number_format($a->performance["network"], 2),
 470                                         number_format($a->performance["file"], 2),
 471                                         number_format($duration - ($a->performance["database"]
 472                                                 + $a->performance["cache"] + $a->performance["cache_write"]
 473                                                 + $a->performance["network"] + $a->performance["file"]), 2),
 474                                         number_format($duration, 2)
 475                                 ),
 476                                 Logger::DEBUG
 477                         );
 478                 }
 479
 480                 $cooldown = Config::get("system", "worker_cooldown", 0);
 481
 482                 if ($cooldown > 0) {
 483                         Logger::log("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - in cooldown for ".$cooldown." seconds");
 484                         sleep($cooldown);
 485                 }
 486         }
 487
 488         /**
 489          * @brief Checks if the number of database connections has reached a critical limit.
 490          *
 491          * @return bool Are more than 3/4 of the maximum connections used?
 492          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 493          */
 494         private static function maxConnectionsReached()
 495         {
 496                 // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 497                 $max = Config::get("system", "max_connections");
 498
 499                 // Fetch the percentage level where the worker will get active
 500                 $maxlevel = Config::get("system", "max_connections_level", 75);
 501
 502                 if ($max == 0) {
 503                         // the maximum number of possible user connections can be a system variable
 504                         $r = DBA::fetchFirst("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 505                         if (DBA::isResult($r)) {
 506                                 $max = $r["Value"];
 507                         }
 508                         // Or it can be granted. This overrides the system variable
 509                         $r = DBA::p('SHOW GRANTS');
 510                         while ($grants = DBA::fetch($r)) {
 511                                 $grant = array_pop($grants);
 512                                 if (stristr($grant, "GRANT USAGE ON")) {
 513                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match)) {
 514                                                 $max = $match[1];
 515                                         }
 516                                 }
 517                         }
 518                         DBA::close($r);
 519                 }
 520
 521                 // If $max is set we will use the processlist to determine the current number of connections
 522                 // The processlist only shows entries of the current user
 523                 if ($max != 0) {
 524                         $r = DBA::p('SHOW PROCESSLIST');
 525                         $used = DBA::numRows($r);
 526                         DBA::close($r);
 527
 528                         Logger::log("Connection usage (user values): ".$used."/".$max, Logger::DEBUG);
 529
 530                         $level = ($used / $max) * 100;
 531
 532                         if ($level >= $maxlevel) {
 533                                 Logger::log("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
 534                                 return true;
 535                         }
 536                 }
 537
 538                 // We will now check for the system values.
 539                 // This limit could be reached although the user limits are fine.
 540                 $r = DBA::fetchFirst("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 541                 if (!DBA::isResult($r)) {
 542                         return false;
 543                 }
 544                 $max = intval($r["Value"]);
 545                 if ($max == 0) {
 546                         return false;
 547                 }
 548                 $r = DBA::fetchFirst("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 549                 if (!DBA::isResult($r)) {
 550                         return false;
 551                 }
 552                 $used = intval($r["Value"]);
 553                 if ($used == 0) {
 554                         return false;
 555                 }
 556                 Logger::log("Connection usage (system values): ".$used."/".$max, Logger::DEBUG);
 557
 558                 $level = $used / $max * 100;
 559
 560                 if ($level < $maxlevel) {
 561                         return false;
 562                 }
 563                 Logger::log("Maximum level (".$level."%) of system connections reached: ".$used."/".$max);
 564                 return true;
 565         }
 566
 567         /**
 568          * @brief fix the queue entry if the worker process died
 569          * @return void
 570          * @throws \Exception
 571          */
 572         private static function killStaleWorkers()
 573         {
 574                 $entries = DBA::select(
 575                         'workerqueue',
 576                         ['id', 'pid', 'executed', 'priority', 'parameter'],
 577                         ['NOT `done` AND `pid` != 0'],
 578                         ['order' => ['priority', 'created']]
 579                 );
 580
 581                 while ($entry = DBA::fetch($entries)) {
 582                         if (!posix_kill($entry["pid"], 0)) {
 583                                 DBA::update(
 584                                         'workerqueue',
 585                                         ['executed' => DBA::NULL_DATETIME, 'pid' => 0],
 586                                         ['id' => $entry["id"]]
 587                                 );
 588                         } else {
 589                                 // Kill long running processes
 590                                 // Check if the priority is in a valid range
 591                                 if (!in_array($entry["priority"], [PRIORITY_CRITICAL, PRIORITY_HIGH, PRIORITY_MEDIUM, PRIORITY_LOW, PRIORITY_NEGLIGIBLE])) {
 592                                         $entry["priority"] = PRIORITY_MEDIUM;
 593                                 }
 594
 595                                 // Define the maximum durations
 596                                 $max_duration_defaults = [PRIORITY_CRITICAL => 720, PRIORITY_HIGH => 10, PRIORITY_MEDIUM => 60, PRIORITY_LOW => 180, PRIORITY_NEGLIGIBLE => 720];
 597                                 $max_duration = $max_duration_defaults[$entry["priority"]];
 598
 599                                 $argv = json_decode($entry["parameter"], true);
 600                                 $argv[0] = basename($argv[0]);
 601
 602                                 // How long is the process already running?
 603                                 $duration = (time() - strtotime($entry["executed"])) / 60;
 604                                 if ($duration > $max_duration) {
 605                                         Logger::log("Worker process ".$entry["pid"]." (".substr(json_encode($argv), 0, 50).") took more than ".$max_duration." minutes. It will be killed now.");
 606                                         posix_kill($entry["pid"], SIGTERM);
 607
 608                                         // We killed the stale process.
 609                                         // To avoid a blocking situation we reschedule the process at the beginning of the queue.
 610                                         // Additionally we are lowering the priority. (But not PRIORITY_CRITICAL)
 611                                         $new_priority = $entry["priority"];
 612                                         if ($entry["priority"] == PRIORITY_HIGH) {
 613                                                 $new_priority = PRIORITY_MEDIUM;
 614                                         } elseif ($entry["priority"] == PRIORITY_MEDIUM) {
 615                                                 $new_priority = PRIORITY_LOW;
 616                                         } elseif ($entry["priority"] != PRIORITY_CRITICAL) {
 617                                                 $new_priority = PRIORITY_NEGLIGIBLE;
 618                                         }
 619                                         DBA::update(
 620                                                 'workerqueue',
 621                                                 ['executed' => DBA::NULL_DATETIME, 'created' => DateTimeFormat::utcNow(), 'priority' => $new_priority, 'pid' => 0],
 622                                                 ['id' => $entry["id"]]
 623                                         );
 624                                 } else {
 625                                         Logger::log("Worker process ".$entry["pid"]." (".substr(json_encode($argv), 0, 50).") now runs for ".round($duration)." of ".$max_duration." allowed minutes. That's okay.", Logger::DEBUG);
 626                                 }
 627                         }
 628                 }
 629         }
 630
 631         /**
 632          * @brief Checks if the number of active workers exceeds the given limits
 633          *
 634          * @return bool Are there too much workers running?
 635          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 636          */
 637         public static function tooMuchWorkers()
 638         {
 639                 $queues = Config::get("system", "worker_queues", 4);
 640
 641                 $maxqueues = $queues;
 642
 643                 $active = self::activeWorkers();
 644
 645                 // Decrease the number of workers at higher load
 646                 $load = System::currentLoad();
 647                 if ($load) {
 648                         $maxsysload = intval(Config::get("system", "maxloadavg", 50));
 649
 650                         /* Default exponent 3 causes queues to rapidly decrease as load increases.
 651                          * If you have 20 max queues at idle, then you get only 5 queues at 37.1% of $maxsysload.
 652                          * For some environments, this rapid decrease is not needed.
 653                          * With exponent 1, you could have 20 max queues at idle and 13 at 37% of $maxsysload.
 654                          */
 655                         $exponent = intval(Config::get('system', 'worker_load_exponent', 3));
 656                         $slope = pow(max(0, $maxsysload - $load) / $maxsysload, $exponent);
 657                         $queues = intval(ceil($slope * $maxqueues));
 658
 659                         $processlist = '';
 660
 661                         if (Config::get('system', 'worker_jpm')) {
 662                                 $intervals = [1, 10, 60];
 663                                 $jobs_per_minute = [];
 664                                 foreach ($intervals as $interval) {
 665                                         $jobs = DBA::p("SELECT COUNT(*) AS `jobs` FROM `workerqueue` WHERE `done` AND `executed` > UTC_TIMESTAMP() - INTERVAL ? MINUTE", $interval);
 666                                         if ($job = DBA::fetch($jobs)) {
 667                                                 $jobs_per_minute[$interval] = number_format($job['jobs'] / $interval, 0);
 668                                         }
 669                                         DBA::close($jobs);
 670                                 }
 671                                 $processlist = ' - jpm: '.implode('/', $jobs_per_minute);
 672                         }
 673
 674                         if (Config::get('system', 'worker_debug')) {
 675                                 // Create a list of queue entries grouped by their priority
 676                                 $listitem = [0 => ''];
 677
 678                                 $idle_workers = $active;
 679
 680                                 // Now adding all processes with workerqueue entries
 681                                 $entries = DBA::p("SELECT COUNT(*) AS `entries`, `priority` FROM `workerqueue` WHERE NOT `done` GROUP BY `priority`");
 682                                 while ($entry = DBA::fetch($entries)) {
 683                                         $processes = DBA::p("SELECT COUNT(*) AS `running` FROM `process` INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` WHERE NOT `done` AND `priority` = ?", $entry["priority"]);
 684                                         if ($process = DBA::fetch($processes)) {
 685                                                 $idle_workers -= $process["running"];
 686                                                 $listitem[$entry["priority"]] = $entry["priority"].":".$process["running"]."/".$entry["entries"];
 687                                         }
 688                                         DBA::close($processes);
 689                                 }
 690                                 DBA::close($entries);
 691
 692                                 $listitem[0] = "0:" . max(0, $idle_workers);
 693
 694                                 $processlist .= ' ('.implode(', ', $listitem).')';
 695                         }
 696
 697                         $deferred = self::deferredEntries();
 698                         $entries = max(self::totalEntries() - $deferred, 0);
 699
 700                         if (Config::get("system", "worker_fastlane", false) && ($queues > 0) && ($entries > 0) && ($active >= $queues)) {
 701                                 $top_priority = self::highestPriority();
 702                                 $high_running = self::processWithPriorityActive($top_priority);
 703
 704                                 if (!$high_running && ($top_priority > PRIORITY_UNDEFINED) && ($top_priority < PRIORITY_NEGLIGIBLE)) {
 705                                         Logger::log("There are jobs with priority ".$top_priority." waiting but none is executed. Open a fastlane.", Logger::DEBUG);
 706                                         $queues = $active + 1;
 707                                 }
 708                         }
 709
 710                         Logger::log("Load: " . $load ."/" . $maxsysload . " - processes: " . $deferred . "/" . $active . "/" . $entries . $processlist . " - maximum: " . $queues . "/" . $maxqueues, Logger::DEBUG);
 711
 712                         // Are there fewer workers running as possible? Then fork a new one.
 713                         if (!Config::get("system", "worker_dont_fork", false) && ($queues > ($active + 1)) && ($entries > 1)) {
 714                                 Logger::log("Active workers: ".$active."/".$queues." Fork a new worker.", Logger::DEBUG);
 715                                 if (Config::get('system', 'worker_daemon_mode', false)) {
 716                                         self::IPCSetJobState(true);
 717                                 } else {
 718                                         self::spawnWorker();
 719                                 }
 720                         }
 721                 }
 722
 723                 // if there are too much worker, we don't spawn a new one.
 724                 if (Config::get('system', 'worker_daemon_mode', false) && ($active > $queues)) {
 725                         self::IPCSetJobState(false);
 726                 }
 727
 728                 return $active > $queues;
 729         }
 730
 731         /**
 732          * @brief Returns the number of active worker processes
 733          *
 734          * @return integer Number of active worker processes
 735          * @throws \Exception
 736          */
 737         private static function activeWorkers()
 738         {
 739                 return DBA::count('process', ['command' => 'Worker.php']);
 740         }
 741
 742         /**
 743          * @brief Check if we should pass some slow processes
 744          *
 745          * When the active processes of the highest priority are using more than 2/3
 746          * of all processes, we let pass slower processes.
 747          *
 748          * @param string $highest_priority Returns the currently highest priority
 749          * @return bool We let pass a slower process than $highest_priority
 750          * @throws \Exception
 751          */
 752         private static function passingSlow(&$highest_priority)
 753         {
 754                 $highest_priority = 0;
 755
 756                 $r = DBA::p(
 757                         "SELECT `priority`
 758                                 FROM `process`
 759                                 INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done`"
 760                 );
 761
 762                 // No active processes at all? Fine
 763                 if (!DBA::isResult($r)) {
 764                         return false;
 765                 }
 766                 $priorities = [];
 767                 while ($line = DBA::fetch($r)) {
 768                         $priorities[] = $line["priority"];
 769                 }
 770                 DBA::close($r);
 771
 772                 // Should not happen
 773                 if (count($priorities) == 0) {
 774                         return false;
 775                 }
 776                 $highest_priority = min($priorities);
 777
 778                 // The highest process is already the slowest one?
 779                 // Then we quit
 780                 if ($highest_priority == PRIORITY_NEGLIGIBLE) {
 781                         return false;
 782                 }
 783                 $high = 0;
 784                 foreach ($priorities as $priority) {
 785                         if ($priority == $highest_priority) {
 786                                 ++$high;
 787                         }
 788                 }
 789                 Logger::log("Highest priority: ".$highest_priority." Total processes: ".count($priorities)." Count high priority processes: ".$high, Logger::DEBUG);
 790                 $passing_slow = (($high/count($priorities)) > (2/3));
 791
 792                 if ($passing_slow) {
 793                         Logger::log("Passing slower processes than priority ".$highest_priority, Logger::DEBUG);
 794                 }
 795                 return $passing_slow;
 796         }
 797
 798         /**
 799          * @brief Find and claim the next worker process for us
 800          *
 801          * @param boolean $passing_slow Returns if we had passed low priority processes
 802          * @param integer $entries Total number of queue entries
 803          * @param integer $deferred Number of deferred queue entries
 804          * @return boolean Have we found something?
 805          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 806          */
 807         private static function findWorkerProcesses(&$passing_slow, $entries, $deferred)
 808         {
 809                 $mypid = getmypid();
 810
 811                 // Check if we should pass some low priority process
 812                 $highest_priority = 0;
 813                 $found = false;
 814                 $passing_slow = false;
 815
 816                 // The higher the number of parallel workers, the more we prefetch to prevent concurring access
 817                 // We decrease the limit with the number of entries left in the queue
 818                 $worker_queues = Config::get("system", "worker_queues", 4);
 819                 $queue_length = Config::get('system', 'worker_fetch_limit', 1);
 820                 $lower_job_limit = $worker_queues * $queue_length * 2;
 821                 $entries = max($entries - $deferred, 0);
 822
 823                 // Now do some magic
 824                 $exponent = 2;
 825                 $slope = $queue_length / pow($lower_job_limit, $exponent);
 826                 $limit = min($queue_length, ceil($slope * pow($entries, $exponent)));
 827
 828                 Logger::log('Deferred: ' . $deferred . ' - Total: ' . $entries . ' - Maximum: ' . $queue_length . ' - jobs per queue: ' . $limit, Logger::DEBUG);
 829                 $ids = [];
 830                 if (self::passingSlow($highest_priority)) {
 831                         // Are there waiting processes with a higher priority than the currently highest?
 832                         $result = DBA::select(
 833                                 'workerqueue',
 834                                 ['id'],
 835                                 ["`pid` = 0 AND `priority` < ? AND NOT `done` AND `next_try` < ?",
 836                                 $highest_priority, DateTimeFormat::utcNow()],
 837                                 ['limit' => $limit, 'order' => ['priority', 'created']]
 838                         );
 839
 840                         while ($id = DBA::fetch($result)) {
 841                                 $ids[] = $id["id"];
 842                         }
 843                         DBA::close($result);
 844
 845                         $found = (count($ids) > 0);
 846
 847                         if (!$found) {
 848                                 // Give slower processes some processing time
 849                                 $result = DBA::select(
 850                                         'workerqueue',
 851                                         ['id'],
 852                                         ["`pid` = 0 AND `priority` > ? AND NOT `done` AND `next_try` < ?",
 853                                         $highest_priority, DateTimeFormat::utcNow()],
 854                                         ['limit' => $limit, 'order' => ['priority', 'created']]
 855                                 );
 856
 857                                 while ($id = DBA::fetch($result)) {
 858                                         $ids[] = $id["id"];
 859                                 }
 860                                 DBA::close($result);
 861
 862                                 $found = (count($ids) > 0);
 863                                 $passing_slow = $found;
 864                         }
 865                 }
 866
 867                 // If there is no result (or we shouldn't pass lower processes) we check without priority limit
 868                 if (!$found) {
 869                         $result = DBA::select(
 870                                 'workerqueue',
 871                                 ['id'],
 872                                 ["`pid` = 0 AND NOT `done` AND `next_try` < ?",
 873                                 DateTimeFormat::utcNow()],
 874                                 ['limit' => $limit, 'order' => ['priority', 'created']]
 875                         );
 876
 877                         while ($id = DBA::fetch($result)) {
 878                                 $ids[] = $id["id"];
 879                         }
 880                         DBA::close($result);
 881
 882                         $found = (count($ids) > 0);
 883                 }
 884
 885                 if ($found) {
 886                         $condition = "`id` IN (".substr(str_repeat("?, ", count($ids)), 0, -2).") AND `pid` = 0 AND NOT `done`";
 887                         array_unshift($ids, $condition);
 888                         DBA::update('workerqueue', ['executed' => DateTimeFormat::utcNow(), 'pid' => $mypid], $ids);
 889                 }
 890
 891                 return $found;
 892         }
 893
 894         /**
 895          * @brief Returns the next worker process
 896          *
 897          * @param boolean $passing_slow Returns if we had passed low priority processes
 898          * @return string SQL statement
 899          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 900          */
 901         public static function workerProcess(&$passing_slow)
 902         {
 903                 $stamp = (float)microtime(true);
 904
 905                 // There can already be jobs for us in the queue.
 906                 $r = DBA::select('workerqueue', [], ['pid' => getmypid(), 'done' => false]);
 907                 if (DBA::isResult($r)) {
 908                         self::$db_duration += (microtime(true) - $stamp);
 909                         return DBA::toArray($r);
 910                 }
 911                 DBA::close($r);
 912
 913                 $stamp = (float)microtime(true);
 914
 915                 // Counting the rows outside the lock reduces the lock time
 916                 $entries = self::totalEntries();
 917                 $deferred = self::deferredEntries();
 918
 919                 if (!Lock::acquire('worker_process')) {
 920                         return false;
 921                 }
 922                 self::$lock_duration = (microtime(true) - $stamp);
 923
 924                 $stamp = (float)microtime(true);
 925                 $found = self::findWorkerProcesses($passing_slow, $entries, $deferred);
 926                 self::$db_duration += (microtime(true) - $stamp);
 927
 928                 Lock::release('worker_process');
 929
 930                 if ($found) {
 931                         $r = DBA::select('workerqueue', [], ['pid' => getmypid(), 'done' => false]);
 932                         return DBA::toArray($r);
 933                 }
 934                 return false;
 935         }
 936
 937         /**
 938          * @brief Removes a workerqueue entry from the current process
 939          * @return void
 940          * @throws \Exception
 941          */
 942         public static function unclaimProcess()
 943         {
 944                 $mypid = getmypid();
 945
 946                 DBA::update('workerqueue', ['executed' => DBA::NULL_DATETIME, 'pid' => 0], ['pid' => $mypid, 'done' => false]);
 947         }
 948
 949         /**
 950          * @brief Call the front end worker
 951          * @return void
 952          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 953          */
 954         public static function callWorker()
 955         {
 956                 if (!Config::get("system", "frontend_worker")) {
 957                         return;
 958                 }
 959
 960                 $url = System::baseUrl()."/worker";
 961                 Network::fetchUrl($url, false, $redirects, 1);
 962         }
 963
 964         /**
 965          * @brief Call the front end worker if there aren't any active
 966          * @return void
 967          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 968          */
 969         public static function executeIfIdle()
 970         {
 971                 if (!Config::get("system", "frontend_worker")) {
 972                         return;
 973                 }
 974
 975                 // Do we have "proc_open"? Then we can fork the worker
 976                 if (function_exists("proc_open")) {
 977                         // When was the last time that we called the worker?
 978                         // Less than one minute? Then we quit
 979                         if ((time() - Config::get("system", "worker_started")) < 60) {
 980                                 return;
 981                         }
 982
 983                         Config::set("system", "worker_started", time());
 984
 985                         // Do we have enough running workers? Then we quit here.
 986                         if (self::tooMuchWorkers()) {
 987                                 // Cleaning dead processes
 988                                 self::killStaleWorkers();
 989                                 Process::deleteInactive();
 990
 991                                 return;
 992                         }
 993
 994                         self::runCron();
 995
 996                         Logger::log('Call worker', Logger::DEBUG);
 997                         self::spawnWorker();
 998                         return;
 999                 }
1000
1001                 // We cannot execute background processes.
1002                 // We now run the processes from the frontend.
1003                 // This won't work with long running processes.
1004                 self::runCron();
1005
1006                 self::clearProcesses();
1007
1008                 $workers = self::activeWorkers();
1009
1010                 if ($workers == 0) {
1011                         self::callWorker();
1012                 }
1013         }
1014
1015         /**
1016          * @brief Removes long running worker processes
1017          * @return void
1018          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1019          */
1020         public static function clearProcesses()
1021         {
1022                 $timeout = Config::get("system", "frontend_worker_timeout", 10);
1023
1024                 /// @todo We should clean up the corresponding workerqueue entries as well
1025                 $condition = ["`created` < ? AND `command` = 'worker.php'",
1026                                 DateTimeFormat::utc("now - ".$timeout." minutes")];
1027                 DBA::delete('process', $condition);
1028         }
1029
1030         /**
1031          * @brief Runs the cron processes
1032          * @return void
1033          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1034          */
1035         private static function runCron()
1036         {
1037                 Logger::log('Add cron entries', Logger::DEBUG);
1038
1039                 // Check for spooled items
1040                 self::add(['priority' => PRIORITY_HIGH, 'force_priority' => true], 'SpoolPost');
1041
1042                 // Run the cron job that calls all other jobs
1043                 self::add(['priority' => PRIORITY_MEDIUM, 'force_priority' => true], 'Cron');
1044
1045                 // Cleaning dead processes
1046                 self::killStaleWorkers();
1047         }
1048
1049         /**
1050          * @brief Spawns a new worker
1051          * @param bool $do_cron
1052          * @return void
1053          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1054          */
1055         public static function spawnWorker($do_cron = false)
1056         {
1057                 $command = 'bin/worker.php';
1058
1059                 $args = ['no_cron' => !$do_cron];
1060
1061                 get_app()->proc_run($command, $args);
1062
1063                 // after spawning we have to remove the flag.
1064                 if (Config::get('system', 'worker_daemon_mode', false)) {
1065                         self::IPCSetJobState(false);
1066                 }
1067         }
1068
1069         /**
1070          * @brief Adds tasks to the worker queue
1071          *
1072          * @param (integer|array) priority or parameter array, strings are deprecated and are ignored
1073          *
1074          * next args are passed as $cmd command line
1075          * or: Worker::add(PRIORITY_HIGH, "Notifier", "drop", $drop_id);
1076          * or: Worker::add(array('priority' => PRIORITY_HIGH, 'dont_fork' => true), "CreateShadowEntry", $post_id);
1077          *
1078          * @return boolean "false" if proc_run couldn't be executed
1079          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1080          * @note $cmd and string args are surrounded with ""
1081          *
1082          * @hooks 'proc_run'
1083          *    array $arr
1084          *
1085          */
1086         public static function add($cmd)
1087         {
1088                 $args = func_get_args();
1089
1090                 if (!count($args)) {
1091                         return false;
1092                 }
1093
1094                 $arr = ['args' => $args, 'run_cmd' => true];
1095
1096                 Hook::callAll("proc_run", $arr);
1097                 if (!$arr['run_cmd'] || !count($args)) {
1098                         return true;
1099                 }
1100
1101                 $priority = PRIORITY_MEDIUM;
1102                 $dont_fork = Config::get("system", "worker_dont_fork", false);
1103                 $created = DateTimeFormat::utcNow();
1104                 $force_priority = false;
1105
1106                 $run_parameter = array_shift($args);
1107
1108                 if (is_int($run_parameter)) {
1109                         $priority = $run_parameter;
1110                 } elseif (is_array($run_parameter)) {
1111                         if (isset($run_parameter['priority'])) {
1112                                 $priority = $run_parameter['priority'];
1113                         }
1114                         if (isset($run_parameter['created'])) {
1115                                 $created = $run_parameter['created'];
1116                         }
1117                         if (isset($run_parameter['dont_fork'])) {
1118                                 $dont_fork = $run_parameter['dont_fork'];
1119                         }
1120                         if (isset($run_parameter['force_priority'])) {
1121                                 $force_priority = $run_parameter['force_priority'];
1122                         }
1123                 }
1124
1125                 $parameters = json_encode($args);
1126                 $found = DBA::exists('workerqueue', ['parameter' => $parameters, 'done' => false]);
1127
1128                 // Quit if there was a database error - a precaution for the update process to 3.5.3
1129                 if (DBA::errorNo() != 0) {
1130                         return false;
1131                 }
1132
1133                 if (!$found) {
1134                         DBA::insert('workerqueue', ['parameter' => $parameters, 'created' => $created, 'priority' => $priority]);
1135                 } elseif ($force_priority) {
1136                         DBA::update('workerqueue', ['priority' => $priority], ['parameter' => $parameters, 'done' => false, 'pid' => 0]);
1137                 }
1138
1139                 // Should we quit and wait for the worker to be called as a cronjob?
1140                 if ($dont_fork) {
1141                         return true;
1142                 }
1143
1144                 // If there is a lock then we don't have to check for too much worker
1145                 if (!Lock::acquire('worker', 0)) {
1146                         return true;
1147                 }
1148
1149                 // If there are already enough workers running, don't fork another one
1150                 $quit = self::tooMuchWorkers();
1151                 Lock::release('worker');
1152
1153                 if ($quit) {
1154                         return true;
1155                 }
1156
1157                 // We tell the daemon that a new job entry exists
1158                 if (Config::get('system', 'worker_daemon_mode', false)) {
1159                         // We don't have to set the IPC flag - this is done in "tooMuchWorkers"
1160                         return true;
1161                 }
1162
1163                 // Now call the worker to execute the jobs that we just added to the queue
1164                 self::spawnWorker();
1165
1166                 return true;
1167         }
1168
1169         /**
1170          * Defers the current worker entry
1171          */
1172         public static function defer()
1173         {
1174                 if (empty(BaseObject::getApp()->queue)) {
1175                         return;
1176                 }
1177
1178                 $queue = BaseObject::getApp()->queue;
1179
1180                 $retrial = $queue['retrial'];
1181                 $id = $queue['id'];
1182                 $priority = $queue['priority'];
1183
1184                 if ($retrial > 14) {
1185                         Logger::log('Id ' . $id . ' had been tried 14 times. We stop now.', Logger::DEBUG);
1186                         return;
1187                 }
1188
1189                 // Calculate the delay until the next trial
1190                 $delay = (($retrial + 3) ** 4) + (rand(1, 30) * ($retrial + 1));
1191                 $next = DateTimeFormat::utc('now + ' . $delay . ' seconds');
1192
1193                 if (($priority < PRIORITY_MEDIUM) && ($retrial > 2)) {
1194                         $priority = PRIORITY_MEDIUM;
1195                 } elseif (($priority < PRIORITY_LOW) && ($retrial > 5)) {
1196                         $priority = PRIORITY_LOW;
1197                 } elseif (($priority < PRIORITY_NEGLIGIBLE) && ($retrial > 7)) {
1198                         $priority = PRIORITY_NEGLIGIBLE;
1199                 }
1200
1201                 Logger::log('Defer execution ' . $retrial . ' of id ' . $id . ' to ' . $next . ' - priority old/new: ' . $queue['priority'] . '/' . $priority, Logger::DEBUG);
1202
1203                 $fields = ['retrial' => $retrial + 1, 'next_try' => $next, 'executed' => DBA::NULL_DATETIME, 'pid' => 0, 'priority' => $priority];
1204                 DBA::update('workerqueue', $fields, ['id' => $id]);
1205         }
1206
1207         /**
1208          * Log active processes into the "process" table
1209          *
1210          * @brief Log active processes into the "process" table
1211          */
1212         public static function startProcess()
1213         {
1214                 $trace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 1);
1215
1216                 $command = basename($trace[0]['file']);
1217
1218                 Process::deleteInactive();
1219
1220                 Process::insert($command);
1221         }
1222
1223         /**
1224          * Remove the active process from the "process" table
1225          *
1226          * @brief Remove the active process from the "process" table
1227          * @return bool
1228          * @throws \Exception
1229          */
1230         public static function endProcess()
1231         {
1232                 return Process::deleteByPid();
1233         }
1234
1235         /**
1236          * Set the flag if some job is waiting
1237          *
1238          * @brief Set the flag if some job is waiting
1239          * @param boolean $jobs Is there a waiting job?
1240          * @throws \Exception
1241          */
1242         public static function IPCSetJobState($jobs)
1243         {
1244                 DBA::update('worker-ipc', ['jobs' => $jobs], ['key' => 1], true);
1245         }
1246
1247         /**
1248          * Checks if some worker job waits to be executed
1249          *
1250          * @brief Checks if some worker job waits to be executed
1251          * @return bool
1252          * @throws \Exception
1253          */
1254         public static function IPCJobsExists()
1255         {
1256                 $row = DBA::selectFirst('worker-ipc', ['jobs'], ['key' => 1]);
1257
1258                 // When we don't have a row, no job is running
1259                 if (!DBA::isResult($row)) {
1260                         return false;
1261                 }
1262
1263                 return (bool)$row['jobs'];
1264         }
1265 }