include/poller.php

   1 <?php
   2
   3 use Friendica\App;
   4 use Friendica\Core\System;
   5 use Friendica\Core\Config;
   6 use Friendica\Util\Lock;
   7
   8 if (!file_exists("boot.php") && (sizeof($_SERVER["argv"]) != 0)) {
   9         $directory = dirname($_SERVER["argv"][0]);
  10
  11         if (substr($directory, 0, 1) != "/") {
  12                 $directory = $_SERVER["PWD"]."/".$directory;
  13         }
  14         $directory = realpath($directory."/..");
  15
  16         chdir($directory);
  17 }
  18
  19 require_once("boot.php");
  20
  21 function poller_run($argv, $argc){
  22         global $a, $db, $poller_up_start, $poller_db_duration;
  23
  24         $poller_up_start = microtime(true);
  25
  26         $a = new App(dirname(__DIR__));
  27
  28         @include(".htconfig.php");
  29         require_once("include/dba.php");
  30         $db = new dba($db_host, $db_user, $db_pass, $db_data);
  31         unset($db_host, $db_user, $db_pass, $db_data);
  32
  33         Config::load();
  34
  35         // Quit when in maintenance
  36         if (Config::get('system', 'maintenance', true)) {
  37                 return;
  38         }
  39
  40         $a->set_baseurl(Config::get('system', 'url'));
  41
  42         load_hooks();
  43
  44         // At first check the maximum load. We shouldn't continue with a high load
  45         if ($a->maxload_reached()) {
  46                 logger('Pre check: maximum load reached, quitting.', LOGGER_DEBUG);
  47                 return;
  48         }
  49
  50         // We now start the process. This is done after the load check since this could increase the load.
  51         $a->start_process();
  52
  53         // Kill stale processes every 5 minutes
  54         $last_cleanup = Config::get('system', 'poller_last_cleaned', 0);
  55         if (time() > ($last_cleanup + 300)) {
  56                 Config::set('system', 'poller_last_cleaned', time());
  57                 poller_kill_stale_workers();
  58         }
  59
  60         // Count active workers and compare them with a maximum value that depends on the load
  61         if (poller_too_much_workers()) {
  62                 logger('Pre check: Active worker limit reached, quitting.', LOGGER_DEBUG);
  63                 return;
  64         }
  65
  66         // Do we have too few memory?
  67         if ($a->min_memory_reached()) {
  68                 logger('Pre check: Memory limit reached, quitting.', LOGGER_DEBUG);
  69                 return;
  70         }
  71
  72         // Possibly there are too much database connections
  73         if (poller_max_connections_reached()) {
  74                 logger('Pre check: maximum connections reached, quitting.', LOGGER_DEBUG);
  75                 return;
  76         }
  77
  78         // Possibly there are too much database processes that block the system
  79         if ($a->max_processes_reached()) {
  80                 logger('Pre check: maximum processes reached, quitting.', LOGGER_DEBUG);
  81                 return;
  82         }
  83
  84         // Now we start additional cron processes if we should do so
  85         if (($argc <= 1) || ($argv[1] != "no_cron")) {
  86                 poller_run_cron();
  87         }
  88
  89         $starttime = time();
  90
  91         // We fetch the next queue entry that is about to be executed
  92         while ($r = poller_worker_process($passing_slow)) {
  93
  94                 // When we are processing jobs with a lower priority, we don't refetch new jobs
  95                 // Otherwise fast jobs could wait behind slow ones and could be blocked.
  96                 $refetched = $passing_slow;
  97
  98                 foreach ($r AS $entry) {
  99                         // Assure that the priority is an integer value
 100                         $entry['priority'] = (int)$entry['priority'];
 101
 102                         // The work will be done
 103                         if (!poller_execute($entry)) {
 104                                 logger('Process execution failed, quitting.', LOGGER_DEBUG);
 105                                 return;
 106                         }
 107
 108                         // If possible we will fetch new jobs for this worker
 109                         if (!$refetched && Lock::set('poller_worker_process', 0)) {
 110                                 $stamp = (float)microtime(true);
 111                                 $refetched = find_worker_processes($passing_slow);
 112                                 $poller_db_duration += (microtime(true) - $stamp);
 113                                 Lock::remove('poller_worker_process');
 114                         }
 115                 }
 116
 117                 // To avoid the quitting of multiple pollers only one poller at a time will execute the check
 118                 if (Lock::set('poller_worker', 0)) {
 119                         $stamp = (float)microtime(true);
 120                         // Count active workers and compare them with a maximum value that depends on the load
 121                         if (poller_too_much_workers()) {
 122                                 logger('Active worker limit reached, quitting.', LOGGER_DEBUG);
 123                                 return;
 124                         }
 125
 126                         // Check free memory
 127                         if ($a->min_memory_reached()) {
 128                                 logger('Memory limit reached, quitting.', LOGGER_DEBUG);
 129                                 return;
 130                         }
 131                         Lock::remove('poller_worker');
 132                         $poller_db_duration += (microtime(true) - $stamp);
 133                 }
 134
 135                 // Quit the poller once every 5 minutes
 136                 if (time() > ($starttime + 300)) {
 137                         logger('Process lifetime reached, quitting.', LOGGER_DEBUG);
 138                         return;
 139                 }
 140         }
 141         logger("Couldn't select a workerqueue entry, quitting.", LOGGER_DEBUG);
 142 }
 143
 144 /**
 145  * @brief Returns the number of non executed entries in the worker queue
 146  *
 147  * @return integer Number of non executed entries in the worker queue
 148  */
 149 function poller_total_entries() {
 150         $s = q("SELECT COUNT(*) AS `total` FROM `workerqueue` WHERE `executed` <= '%s' AND NOT `done`", dbesc(NULL_DATE));
 151         if (dbm::is_result($s)) {
 152                 return $s[0]["total"];
 153         } else {
 154                 return 0;
 155         }
 156 }
 157
 158 /**
 159  * @brief Returns the highest priority in the worker queue that isn't executed
 160  *
 161  * @return integer Number of active poller processes
 162  */
 163 function poller_highest_priority() {
 164         $s = q("SELECT `priority` FROM `workerqueue` WHERE `executed` <= '%s' AND NOT `done` ORDER BY `priority` LIMIT 1", dbesc(NULL_DATE));
 165         if (dbm::is_result($s)) {
 166                 return $s[0]["priority"];
 167         } else {
 168                 return 0;
 169         }
 170 }
 171
 172 /**
 173  * @brief Returns if a process with the given priority is running
 174  *
 175  * @param integer $priority The priority that should be checked
 176  *
 177  * @return integer Is there a process running with that priority?
 178  */
 179 function poller_process_with_priority_active($priority) {
 180         $s = q("SELECT `id` FROM `workerqueue` WHERE `priority` <= %d AND `executed` > '%s' AND NOT `done` LIMIT 1",
 181                         intval($priority), dbesc(NULL_DATE));
 182         return dbm::is_result($s);
 183 }
 184
 185 /**
 186  * @brief Execute a worker entry
 187  *
 188  * @param array $queue Workerqueue entry
 189  *
 190  * @return boolean "true" if further processing should be stopped
 191  */
 192 function poller_execute($queue) {
 193         global $poller_db_duration, $poller_last_update;
 194
 195         $a = get_app();
 196
 197         $mypid = getmypid();
 198
 199         // Quit when in maintenance
 200         if (Config::get('system', 'maintenance', true)) {
 201                 logger("Maintenance mode - quit process ".$mypid, LOGGER_DEBUG);
 202                 return false;
 203         }
 204
 205         // Constantly check the number of parallel database processes
 206         if ($a->max_processes_reached()) {
 207                 logger("Max processes reached for process ".$mypid, LOGGER_DEBUG);
 208                 return false;
 209         }
 210
 211         // Constantly check the number of available database connections to let the frontend be accessible at any time
 212         if (poller_max_connections_reached()) {
 213                 logger("Max connection reached for process ".$mypid, LOGGER_DEBUG);
 214                 return false;
 215         }
 216
 217         $argv = json_decode($queue["parameter"]);
 218
 219         // Check for existance and validity of the include file
 220         $include = $argv[0];
 221
 222         if (!validate_include($include)) {
 223                 logger("Include file ".$argv[0]." is not valid!");
 224                 dba::delete('workerqueue', array('id' => $queue["id"]));
 225                 return true;
 226         }
 227
 228         require_once($include);
 229
 230         $funcname = str_replace(".php", "", basename($argv[0]))."_run";
 231
 232         if (function_exists($funcname)) {
 233
 234                 // We constantly update the "executed" date every minute to avoid being killed too soon
 235                 if (!isset($poller_last_update)) {
 236                         $poller_last_update = strtotime($queue["executed"]);
 237                 }
 238
 239                 $age = (time() - $poller_last_update) / 60;
 240                 $poller_last_update = time();
 241
 242                 if ($age > 1) {
 243                         $stamp = (float)microtime(true);
 244                         dba::update('workerqueue', array('executed' => datetime_convert()), array('pid' => $mypid, 'done' => false));
 245                         $poller_db_duration += (microtime(true) - $stamp);
 246                 }
 247
 248                 poller_exec_function($queue, $funcname, $argv);
 249
 250                 $stamp = (float)microtime(true);
 251                 dba::update('workerqueue', array('done' => true), array('id' => $queue["id"]));
 252                 $poller_db_duration = (microtime(true) - $stamp);
 253         } else {
 254                 logger("Function ".$funcname." does not exist");
 255                 dba::delete('workerqueue', array('id' => $queue["id"]));
 256         }
 257
 258         return true;
 259 }
 260
 261 /**
 262  * @brief Execute a function from the queue
 263  *
 264  * @param array $queue Workerqueue entry
 265  * @param string $funcname name of the function
 266  * @param array $argv Array of values to be passed to the function
 267  */
 268 function poller_exec_function($queue, $funcname, $argv) {
 269         global $poller_up_start, $poller_db_duration, $poller_lock_duration;
 270
 271         $a = get_app();
 272
 273         $mypid = getmypid();
 274
 275         $argc = count($argv);
 276
 277         $new_process_id = uniqid("wrk", true);
 278
 279         logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." ".$queue["parameter"]." - Process PID: ".$new_process_id);
 280
 281         $stamp = (float)microtime(true);
 282
 283         // We use the callstack here to analyze the performance of executed worker entries.
 284         // For this reason the variables have to be initialized.
 285         if (Config::get("system", "profiler")) {
 286                 $a->performance["start"] = microtime(true);
 287                 $a->performance["database"] = 0;
 288                 $a->performance["database_write"] = 0;
 289                 $a->performance["network"] = 0;
 290                 $a->performance["file"] = 0;
 291                 $a->performance["rendering"] = 0;
 292                 $a->performance["parser"] = 0;
 293                 $a->performance["marktime"] = 0;
 294                 $a->performance["markstart"] = microtime(true);
 295                 $a->callstack = array();
 296         }
 297
 298         // For better logging create a new process id for every worker call
 299         // But preserve the old one for the worker
 300         $old_process_id = $a->process_id;
 301         $a->process_id = $new_process_id;
 302         $a->queue = $queue;
 303
 304         $up_duration = number_format(microtime(true) - $poller_up_start, 3);
 305
 306         // Reset global data to avoid interferences
 307         unset($_SESSION);
 308
 309         $funcname($argv, $argc);
 310
 311         $a->process_id = $old_process_id;
 312         unset($a->queue);
 313
 314         $duration = number_format(microtime(true) - $stamp, 3);
 315
 316         $poller_up_start = microtime(true);
 317
 318         /* With these values we can analyze how effective the worker is.
 319          * The database and rest time should be low since this is the unproductive time.
 320          * The execution time is the productive time.
 321          * By changing parameters like the maximum number of workers we can check the effectivness.
 322         */
 323         logger('DB: '.number_format($poller_db_duration, 2).
 324                 ' - Lock: '.number_format($poller_lock_duration, 2).
 325                 ' - Rest: '.number_format($up_duration - $poller_db_duration - $poller_lock_duration, 2).
 326                 ' - Execution: '.number_format($duration, 2), LOGGER_DEBUG);
 327         $poller_lock_duration = 0;
 328
 329         if ($duration > 3600) {
 330                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 1 hour (".round($duration/60, 3).")", LOGGER_DEBUG);
 331         } elseif ($duration > 600) {
 332                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 10 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 333         } elseif ($duration > 300) {
 334                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 5 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 335         } elseif ($duration > 120) {
 336                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 2 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 337         }
 338
 339         logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - done in ".$duration." seconds. Process PID: ".$new_process_id);
 340
 341         // Write down the performance values into the log
 342         if (Config::get("system", "profiler")) {
 343                 $duration = microtime(true)-$a->performance["start"];
 344
 345                 if (Config::get("rendertime", "callstack")) {
 346                         if (isset($a->callstack["database"])) {
 347                                 $o = "\nDatabase Read:\n";
 348                                 foreach ($a->callstack["database"] AS $func => $time) {
 349                                         $time = round($time, 3);
 350                                         if ($time > 0) {
 351                                                 $o .= $func.": ".$time."\n";
 352                                         }
 353                                 }
 354                         }
 355                         if (isset($a->callstack["database_write"])) {
 356                                 $o .= "\nDatabase Write:\n";
 357                                 foreach ($a->callstack["database_write"] AS $func => $time) {
 358                                         $time = round($time, 3);
 359                                         if ($time > 0) {
 360                                                 $o .= $func.": ".$time."\n";
 361                                         }
 362                                 }
 363                         }
 364                         if (isset($a->callstack["network"])) {
 365                                 $o .= "\nNetwork:\n";
 366                                 foreach ($a->callstack["network"] AS $func => $time) {
 367                                         $time = round($time, 3);
 368                                         if ($time > 0) {
 369                                                 $o .= $func.": ".$time."\n";
 370                                         }
 371                                 }
 372                         }
 373                 } else {
 374                         $o = '';
 375                 }
 376
 377                 logger("ID ".$queue["id"].": ".$funcname.": ".sprintf("DB: %s/%s, Net: %s, I/O: %s, Other: %s, Total: %s".$o,
 378                         number_format($a->performance["database"] - $a->performance["database_write"], 2),
 379                         number_format($a->performance["database_write"], 2),
 380                         number_format($a->performance["network"], 2),
 381                         number_format($a->performance["file"], 2),
 382                         number_format($duration - ($a->performance["database"] + $a->performance["network"] + $a->performance["file"]), 2),
 383                         number_format($duration, 2)),
 384                         LOGGER_DEBUG);
 385         }
 386
 387         $cooldown = Config::get("system", "worker_cooldown", 0);
 388
 389         if ($cooldown > 0) {
 390                 logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - in cooldown for ".$cooldown." seconds");
 391                 sleep($cooldown);
 392         }
 393 }
 394
 395 /**
 396  * @brief Checks if the number of database connections has reached a critical limit.
 397  *
 398  * @return bool Are more than 3/4 of the maximum connections used?
 399  */
 400 function poller_max_connections_reached() {
 401
 402         // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 403         $max = Config::get("system", "max_connections");
 404
 405         // Fetch the percentage level where the poller will get active
 406         $maxlevel = Config::get("system", "max_connections_level", 75);
 407
 408         if ($max == 0) {
 409                 // the maximum number of possible user connections can be a system variable
 410                 $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 411                 if (dbm::is_result($r)) {
 412                         $max = $r[0]["Value"];
 413                 }
 414                 // Or it can be granted. This overrides the system variable
 415                 $r = q("SHOW GRANTS");
 416                 if (dbm::is_result($r)) {
 417                         foreach ($r AS $grants) {
 418                                 $grant = array_pop($grants);
 419                                 if (stristr($grant, "GRANT USAGE ON")) {
 420                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match)) {
 421                                                 $max = $match[1];
 422                                         }
 423                                 }
 424                         }
 425                 }
 426         }
 427
 428         // If $max is set we will use the processlist to determine the current number of connections
 429         // The processlist only shows entries of the current user
 430         if ($max != 0) {
 431                 $r = q("SHOW PROCESSLIST");
 432                 if (!dbm::is_result($r)) {
 433                         return false;
 434                 }
 435                 $used = count($r);
 436
 437                 logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
 438
 439                 $level = ($used / $max) * 100;
 440
 441                 if ($level >= $maxlevel) {
 442                         logger("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
 443                         return true;
 444                 }
 445         }
 446
 447         // We will now check for the system values.
 448         // This limit could be reached although the user limits are fine.
 449         $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 450         if (!dbm::is_result($r)) {
 451                 return false;
 452         }
 453         $max = intval($r[0]["Value"]);
 454         if ($max == 0) {
 455                 return false;
 456         }
 457         $r = q("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 458         if (!dbm::is_result($r)) {
 459                 return false;
 460         }
 461         $used = intval($r[0]["Value"]);
 462         if ($used == 0) {
 463                 return false;
 464         }
 465         logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
 466
 467         $level = $used / $max * 100;
 468
 469         if ($level < $maxlevel) {
 470                 return false;
 471         }
 472         logger("Maximum level (".$level."%) of system connections reached: ".$used."/".$max);
 473         return true;
 474 }
 475
 476 /**
 477  * @brief fix the queue entry if the worker process died
 478  *
 479  */
 480 function poller_kill_stale_workers() {
 481         $entries = dba::select('workerqueue', array('id', 'pid', 'executed', 'priority', 'parameter'),
 482                                 array('`executed` > ? AND NOT `done` AND `pid` != 0', NULL_DATE),
 483                                 array('order' => array('priority', 'created')));
 484         while ($entry = dba::fetch($entries)) {
 485                 if (!posix_kill($entry["pid"], 0)) {
 486                         dba::update('workerqueue', array('executed' => NULL_DATE, 'pid' => 0),
 487                                         array('id' => $entry["id"]));
 488                 } else {
 489                         // Kill long running processes
 490                         // Check if the priority is in a valid range
 491                         if (!in_array($entry["priority"], array(PRIORITY_CRITICAL, PRIORITY_HIGH, PRIORITY_MEDIUM, PRIORITY_LOW, PRIORITY_NEGLIGIBLE))) {
 492                                 $entry["priority"] = PRIORITY_MEDIUM;
 493                         }
 494
 495                         // Define the maximum durations
 496                         $max_duration_defaults = array(PRIORITY_CRITICAL => 720, PRIORITY_HIGH => 10, PRIORITY_MEDIUM => 60, PRIORITY_LOW => 180, PRIORITY_NEGLIGIBLE => 720);
 497                         $max_duration = $max_duration_defaults[$entry["priority"]];
 498
 499                         $argv = json_decode($entry["parameter"]);
 500                         $argv[0] = basename($argv[0]);
 501
 502                         // How long is the process already running?
 503                         $duration = (time() - strtotime($entry["executed"])) / 60;
 504                         if ($duration > $max_duration) {
 505                                 logger("Worker process ".$entry["pid"]." (".implode(" ", $argv).") took more than ".$max_duration." minutes. It will be killed now.");
 506                                 posix_kill($entry["pid"], SIGTERM);
 507
 508                                 // We killed the stale process.
 509                                 // To avoid a blocking situation we reschedule the process at the beginning of the queue.
 510                                 // Additionally we are lowering the priority. (But not PRIORITY_CRITICAL)
 511                                 if ($entry["priority"] == PRIORITY_HIGH) {
 512                                         $new_priority = PRIORITY_MEDIUM;
 513                                 } elseif ($entry["priority"] == PRIORITY_MEDIUM) {
 514                                         $new_priority = PRIORITY_LOW;
 515                                 } elseif ($entry["priority"] != PRIORITY_CRITICAL) {
 516                                         $new_priority = PRIORITY_NEGLIGIBLE;
 517                                 }
 518                                 dba::update('workerqueue',
 519                                                 array('executed' => NULL_DATE, 'created' => datetime_convert(), 'priority' => $new_priority, 'pid' => 0),
 520                                                 array('id' => $entry["id"]));
 521                         } else {
 522                                 logger("Worker process ".$entry["pid"]." (".implode(" ", $argv).") now runs for ".round($duration)." of ".$max_duration." allowed minutes. That's okay.", LOGGER_DEBUG);
 523                         }
 524                 }
 525         }
 526 }
 527
 528 /**
 529  * @brief Checks if the number of active workers exceeds the given limits
 530  *
 531  * @return bool Are there too much workers running?
 532  */
 533 function poller_too_much_workers() {
 534         $queues = Config::get("system", "worker_queues", 4);
 535
 536         $maxqueues = $queues;
 537
 538         $active = poller_active_workers();
 539
 540         // Decrease the number of workers at higher load
 541         $load = current_load();
 542         if ($load) {
 543                 $maxsysload = intval(Config::get("system", "maxloadavg", 50));
 544
 545                 $maxworkers = $queues;
 546
 547                 // Some magical mathemathics to reduce the workers
 548                 $exponent = 3;
 549                 $slope = $maxworkers / pow($maxsysload, $exponent);
 550                 $queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
 551
 552                 if (Config::get('system', 'worker_debug')) {
 553                         // Create a list of queue entries grouped by their priority
 554                         $listitem = array();
 555
 556                         // Adding all processes with no workerqueue entry
 557                         $processes = dba::p("SELECT COUNT(*) AS `running` FROM `process` WHERE NOT EXISTS
 558                                                 (SELECT id FROM `workerqueue`
 559                                                 WHERE `workerqueue`.`pid` = `process`.`pid` AND NOT `done` AND `pid` != ?)", getmypid());
 560                         if ($process = dba::fetch($processes)) {
 561                                 $listitem[0] = "0:".$process["running"];
 562                         }
 563                         dba::close($processes);
 564
 565                         // Now adding all processes with workerqueue entries
 566                         $entries = dba::p("SELECT COUNT(*) AS `entries`, `priority` FROM `workerqueue` WHERE NOT `done` GROUP BY `priority`");
 567                         while ($entry = dba::fetch($entries)) {
 568                                 $processes = dba::p("SELECT COUNT(*) AS `running` FROM `process` INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done` WHERE `priority` = ?", $entry["priority"]);
 569                                 if ($process = dba::fetch($processes)) {
 570                                         $listitem[$entry["priority"]] = $entry["priority"].":".$process["running"]."/".$entry["entries"];
 571                                 }
 572                                 dba::close($processes);
 573                         }
 574                         dba::close($entries);
 575
 576                         $intervals = array(1, 10, 60);
 577                         $jobs_per_minute = array();
 578                         foreach ($intervals AS $interval) {
 579                                 $jobs = dba::p("SELECT COUNT(*) AS `jobs` FROM `workerqueue` WHERE `done` AND `executed` > UTC_TIMESTAMP() - INTERVAL ".intval($interval)." MINUTE");
 580                                 if ($job = dba::fetch($jobs)) {
 581                                         $jobs_per_minute[$interval] = number_format($job['jobs'] / $interval, 0);
 582                                 }
 583                                 dba::close($jobs);
 584                         }
 585                         $processlist = ' - jpm: '.implode('/', $jobs_per_minute).' ('.implode(', ', $listitem).')';
 586                 }
 587
 588                 $entries = poller_total_entries();
 589
 590                 if (Config::get("system", "worker_fastlane", false) && ($queues > 0) && ($entries > 0) && ($active >= $queues)) {
 591                         $top_priority = poller_highest_priority();
 592                         $high_running = poller_process_with_priority_active($top_priority);
 593
 594                         if (!$high_running && ($top_priority > PRIORITY_UNDEFINED) && ($top_priority < PRIORITY_NEGLIGIBLE)) {
 595                                 logger("There are jobs with priority ".$top_priority." waiting but none is executed. Open a fastlane.", LOGGER_DEBUG);
 596                                 $queues = $active + 1;
 597                         }
 598                 }
 599
 600                 logger("Load: ".$load."/".$maxsysload." - processes: ".$active."/".$entries.$processlist." - maximum: ".$queues."/".$maxqueues, LOGGER_DEBUG);
 601
 602                 // Are there fewer workers running as possible? Then fork a new one.
 603                 if (!Config::get("system", "worker_dont_fork") && ($queues > ($active + 1)) && ($entries > 1)) {
 604                         logger("Active workers: ".$active."/".$queues." Fork a new worker.", LOGGER_DEBUG);
 605                         $args = array("include/poller.php", "no_cron");
 606                         get_app()->proc_run($args);
 607                 }
 608         }
 609
 610         return $active >= $queues;
 611 }
 612
 613 /**
 614  * @brief Returns the number of active poller processes
 615  *
 616  * @return integer Number of active poller processes
 617  */
 618 function poller_active_workers() {
 619         $workers = q("SELECT COUNT(*) AS `processes` FROM `process` WHERE `command` = 'poller.php'");
 620
 621         return $workers[0]["processes"];
 622 }
 623
 624 /**
 625  * @brief Check if we should pass some slow processes
 626  *
 627  * When the active processes of the highest priority are using more than 2/3
 628  * of all processes, we let pass slower processes.
 629  *
 630  * @param string $highest_priority Returns the currently highest priority
 631  * @return bool We let pass a slower process than $highest_priority
 632  */
 633 function poller_passing_slow(&$highest_priority) {
 634
 635         $highest_priority = 0;
 636
 637         $r = q("SELECT `priority`
 638                 FROM `process`
 639                 INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done`");
 640
 641         // No active processes at all? Fine
 642         if (!dbm::is_result($r)) {
 643                 return false;
 644         }
 645         $priorities = array();
 646         foreach ($r AS $line) {
 647                 $priorities[] = $line["priority"];
 648         }
 649         // Should not happen
 650         if (count($priorities) == 0) {
 651                 return false;
 652         }
 653         $highest_priority = min($priorities);
 654
 655         // The highest process is already the slowest one?
 656         // Then we quit
 657         if ($highest_priority == PRIORITY_NEGLIGIBLE) {
 658                 return false;
 659         }
 660         $high = 0;
 661         foreach ($priorities AS $priority) {
 662                 if ($priority == $highest_priority) {
 663                         ++$high;
 664                 }
 665         }
 666         logger("Highest priority: ".$highest_priority." Total processes: ".count($priorities)." Count high priority processes: ".$high, LOGGER_DEBUG);
 667         $passing_slow = (($high/count($priorities)) > (2/3));
 668
 669         if ($passing_slow) {
 670                 logger("Passing slower processes than priority ".$highest_priority, LOGGER_DEBUG);
 671         }
 672         return $passing_slow;
 673 }
 674
 675 /**
 676  * @brief Find and claim the next worker process for us
 677  *
 678  * @param boolean $passing_slow Returns if we had passed low priority processes
 679  * @return boolean Have we found something?
 680  */
 681 function find_worker_processes(&$passing_slow) {
 682
 683         $mypid = getmypid();
 684
 685         // Check if we should pass some low priority process
 686         $highest_priority = 0;
 687         $found = false;
 688         $passing_slow = false;
 689
 690         // The higher the number of parallel workers, the more we prefetch to prevent concurring access
 691         // We decrease the limit with the number of entries left in the queue
 692         $worker_queues = Config::get("system", "worker_queues", 4);
 693         $queue_length = Config::get('system', 'worker_fetch_limit', $worker_queues);
 694         $lower_job_limit = $worker_queues * $queue_length * 2;
 695         $jobs = poller_total_entries();
 696
 697         // Now do some magic
 698         $exponent = 2;
 699         $slope = $queue_length / pow($lower_job_limit, $exponent);
 700         $limit = min($queue_length, ceil($slope * pow($jobs, $exponent)));
 701
 702         logger('Total: '.$jobs.' - Maximum: '.$queue_length.' - jobs per queue: '.$limit, LOGGER_DEBUG);
 703
 704         if (poller_passing_slow($highest_priority)) {
 705                 // Are there waiting processes with a higher priority than the currently highest?
 706                 $result = dba::select('workerqueue', array('id'), array("`executed` <= ? AND `priority` < ? AND NOT `done`", NULL_DATE, $highest_priority),
 707                                 array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true));
 708
 709                 while ($id = dba::fetch($result)) {
 710                         $ids[] = $id["id"];
 711                 }
 712                 dba::close($result);
 713
 714                 $found = (count($ids) > 0);
 715
 716                 if (!$found) {
 717                         // Give slower processes some processing time
 718                         $result = dba::select('workerqueue', array('id'), array("`executed` <= ? AND `priority` > ? AND NOT `done`", NULL_DATE, $highest_priority),
 719                                         array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true));
 720
 721                         while ($id = dba::fetch($result)) {
 722                                 $ids[] = $id["id"];
 723                         }
 724                         dba::close($result);
 725
 726                         $found = (count($ids) > 0);
 727                         $passing_slow = $found;
 728                 }
 729         }
 730
 731         // If there is no result (or we shouldn't pass lower processes) we check without priority limit
 732         if (!$found) {
 733                 $result = dba::select('workerqueue', array('id'), array("`executed` <= ? AND NOT `done`", NULL_DATE),
 734                                 array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true));
 735
 736                 while ($id = dba::fetch($result)) {
 737                         $ids[] = $id["id"];
 738                 }
 739                 dba::close($result);
 740
 741                 $found = (count($ids) > 0);
 742         }
 743
 744         if ($found) {
 745                 $condition = "`id` IN (".substr(str_repeat("?, ", count($ids)), 0, -2).") AND `pid` = 0 AND NOT `done`";
 746                 array_unshift($ids, $condition);
 747                 dba::update('workerqueue', array('executed' => datetime_convert(), 'pid' => $mypid), $ids);
 748         }
 749
 750         return $found;
 751 }
 752
 753 /**
 754  * @brief Returns the next worker process
 755  *
 756  * @param boolean $passing_slow Returns if we had passed low priority processes
 757  * @return string SQL statement
 758  */
 759 function poller_worker_process(&$passing_slow) {
 760         global $poller_db_duration, $poller_lock_duration;
 761
 762         $stamp = (float)microtime(true);
 763
 764         // There can already be jobs for us in the queue.
 765         $r = q("SELECT * FROM `workerqueue` WHERE `pid` = %d AND NOT `done`", intval(getmypid()));
 766         if (dbm::is_result($r)) {
 767                 $poller_db_duration += (microtime(true) - $stamp);
 768                 return $r;
 769         }
 770
 771         $stamp = (float)microtime(true);
 772         if (!Lock::set('poller_worker_process')) {
 773                 return false;
 774         }
 775         $poller_lock_duration = (microtime(true) - $stamp);
 776
 777         $stamp = (float)microtime(true);
 778         $found = find_worker_processes($passing_slow);
 779         $poller_db_duration += (microtime(true) - $stamp);
 780
 781         Lock::remove('poller_worker_process');
 782
 783         if ($found) {
 784                 $r = q("SELECT * FROM `workerqueue` WHERE `pid` = %d AND NOT `done`", intval(getmypid()));
 785         }
 786         return $r;
 787 }
 788
 789 /**
 790  * @brief Removes a workerqueue entry from the current process
 791  */
 792 function poller_unclaim_process() {
 793         $mypid = getmypid();
 794
 795         dba::update('workerqueue', array('executed' => NULL_DATE, 'pid' => 0), array('pid' => $mypid, 'done' => false));
 796 }
 797
 798 /**
 799  * @brief Call the front end worker
 800  */
 801 function call_worker() {
 802         if (!Config::get("system", "frontend_worker")) {
 803                 return;
 804         }
 805
 806         $url = System::baseUrl()."/worker";
 807         fetch_url($url, false, $redirects, 1);
 808 }
 809
 810 /**
 811  * @brief Call the front end worker if there aren't any active
 812  */
 813 function call_worker_if_idle() {
 814         if (!Config::get("system", "frontend_worker")) {
 815                 return;
 816         }
 817
 818         // Do we have "proc_open"? Then we can fork the poller
 819         if (function_exists("proc_open")) {
 820                 // When was the last time that we called the worker?
 821                 // Less than one minute? Then we quit
 822                 if ((time() - Config::get("system", "worker_started")) < 60) {
 823                         return;
 824                 }
 825
 826                 set_config("system", "worker_started", time());
 827
 828                 // Do we have enough running workers? Then we quit here.
 829                 if (poller_too_much_workers()) {
 830                         // Cleaning dead processes
 831                         poller_kill_stale_workers();
 832                         get_app()->remove_inactive_processes();
 833
 834                         return;
 835                 }
 836
 837                 poller_run_cron();
 838
 839                 logger('Call poller', LOGGER_DEBUG);
 840
 841                 $args = array("include/poller.php", "no_cron");
 842                 get_app()->proc_run($args);
 843                 return;
 844         }
 845
 846         // We cannot execute background processes.
 847         // We now run the processes from the frontend.
 848         // This won't work with long running processes.
 849         poller_run_cron();
 850
 851         clear_worker_processes();
 852
 853         $workers = q("SELECT COUNT(*) AS `processes` FROM `process` WHERE `command` = 'worker.php'");
 854
 855         if ($workers[0]["processes"] == 0) {
 856                 call_worker();
 857         }
 858 }
 859
 860 /**
 861  * @brief Removes long running worker processes
 862  */
 863 function clear_worker_processes() {
 864         $timeout = Config::get("system", "frontend_worker_timeout", 10);
 865
 866         /// @todo We should clean up the corresponding workerqueue entries as well
 867         q("DELETE FROM `process` WHERE `created` < '%s' AND `command` = 'worker.php'",
 868                 dbesc(datetime_convert('UTC','UTC',"now - ".$timeout." minutes")));
 869 }
 870
 871 /**
 872  * @brief Runs the cron processes
 873  */
 874 function poller_run_cron() {
 875         logger('Add cron entries', LOGGER_DEBUG);
 876
 877         // Check for spooled items
 878         proc_run(PRIORITY_HIGH, "include/spool_post.php");
 879
 880         // Run the cron job that calls all other jobs
 881         proc_run(PRIORITY_MEDIUM, "include/cron.php");
 882
 883         // Run the cronhooks job separately from cron for being able to use a different timing
 884         proc_run(PRIORITY_MEDIUM, "include/cronhooks.php");
 885
 886         // Cleaning dead processes
 887         poller_kill_stale_workers();
 888 }
 889
 890 if (array_search(__file__,get_included_files())===0){
 891         poller_run($_SERVER["argv"],$_SERVER["argc"]);
 892
 893         poller_unclaim_process();
 894
 895         get_app()->end_process();
 896
 897         killme();
 898 }