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, $poller_up_start, $poller_db_duration;
  23
  24         $poller_up_start = microtime(true);
  25
  26         $a = new App(dirname(__DIR__));
  27
  28         require_once ".htconfig.php";
  29         require_once "include/dba.php";
  30         dba::connect($db_host, $db_user, $db_pass, $db_data);
  31         unset($db_host, $db_user, $db_pass, $db_data);
  32
  33         Config::load();
  34
  35         // Check the database structure and possibly fixes it
  36         check_db(true);
  37
  38         // Quit when in maintenance
  39         if (Config::get('system', 'maintenance', true)) {
  40                 return;
  41         }
  42
  43         $a->set_baseurl(Config::get('system', 'url'));
  44
  45         load_hooks();
  46
  47         // At first check the maximum load. We shouldn't continue with a high load
  48         if ($a->maxload_reached()) {
  49                 logger('Pre check: maximum load reached, quitting.', LOGGER_DEBUG);
  50                 return;
  51         }
  52
  53         // We now start the process. This is done after the load check since this could increase the load.
  54         $a->start_process();
  55
  56         // Kill stale processes every 5 minutes
  57         $last_cleanup = Config::get('system', 'poller_last_cleaned', 0);
  58         if (time() > ($last_cleanup + 300)) {
  59                 Config::set('system', 'poller_last_cleaned', time());
  60                 poller_kill_stale_workers();
  61         }
  62
  63         // Count active workers and compare them with a maximum value that depends on the load
  64         if (poller_too_much_workers()) {
  65                 logger('Pre check: Active worker limit reached, quitting.', LOGGER_DEBUG);
  66                 return;
  67         }
  68
  69         // Do we have too few memory?
  70         if ($a->min_memory_reached()) {
  71                 logger('Pre check: Memory limit reached, quitting.', LOGGER_DEBUG);
  72                 return;
  73         }
  74
  75         // Possibly there are too much database connections
  76         if (poller_max_connections_reached()) {
  77                 logger('Pre check: maximum connections reached, quitting.', LOGGER_DEBUG);
  78                 return;
  79         }
  80
  81         // Possibly there are too much database processes that block the system
  82         if ($a->max_processes_reached()) {
  83                 logger('Pre check: maximum processes reached, quitting.', LOGGER_DEBUG);
  84                 return;
  85         }
  86
  87         // Now we start additional cron processes if we should do so
  88         if (($argc <= 1) || ($argv[1] != "no_cron")) {
  89                 poller_run_cron();
  90         }
  91
  92         $starttime = time();
  93
  94         // We fetch the next queue entry that is about to be executed
  95         while ($r = poller_worker_process($passing_slow)) {
  96
  97                 // When we are processing jobs with a lower priority, we don't refetch new jobs
  98                 // Otherwise fast jobs could wait behind slow ones and could be blocked.
  99                 $refetched = $passing_slow;
 100
 101                 foreach ($r AS $entry) {
 102                         // Assure that the priority is an integer value
 103                         $entry['priority'] = (int)$entry['priority'];
 104
 105                         // The work will be done
 106                         if (!poller_execute($entry)) {
 107                                 logger('Process execution failed, quitting.', LOGGER_DEBUG);
 108                                 return;
 109                         }
 110
 111                         // If possible we will fetch new jobs for this worker
 112                         if (!$refetched && Lock::set('poller_worker_process', 0)) {
 113                                 $stamp = (float)microtime(true);
 114                                 $refetched = find_worker_processes($passing_slow);
 115                                 $poller_db_duration += (microtime(true) - $stamp);
 116                                 Lock::remove('poller_worker_process');
 117                         }
 118                 }
 119
 120                 // To avoid the quitting of multiple pollers only one poller at a time will execute the check
 121                 if (Lock::set('poller_worker', 0)) {
 122                         $stamp = (float)microtime(true);
 123                         // Count active workers and compare them with a maximum value that depends on the load
 124                         if (poller_too_much_workers()) {
 125                                 logger('Active worker limit reached, quitting.', LOGGER_DEBUG);
 126                                 return;
 127                         }
 128
 129                         // Check free memory
 130                         if ($a->min_memory_reached()) {
 131                                 logger('Memory limit reached, quitting.', LOGGER_DEBUG);
 132                                 return;
 133                         }
 134                         Lock::remove('poller_worker');
 135                         $poller_db_duration += (microtime(true) - $stamp);
 136                 }
 137
 138                 // Quit the poller once every 5 minutes
 139                 if (time() > ($starttime + 300)) {
 140                         logger('Process lifetime reached, quitting.', LOGGER_DEBUG);
 141                         return;
 142                 }
 143         }
 144         logger("Couldn't select a workerqueue entry, quitting.", LOGGER_DEBUG);
 145 }
 146
 147 /**
 148  * @brief Returns the number of non executed entries in the worker queue
 149  *
 150  * @return integer Number of non executed entries in the worker queue
 151  */
 152 function poller_total_entries() {
 153         $s = q("SELECT COUNT(*) AS `total` FROM `workerqueue` WHERE `executed` <= '%s' AND NOT `done`", dbesc(NULL_DATE));
 154         if (dbm::is_result($s)) {
 155                 return $s[0]["total"];
 156         } else {
 157                 return 0;
 158         }
 159 }
 160
 161 /**
 162  * @brief Returns the highest priority in the worker queue that isn't executed
 163  *
 164  * @return integer Number of active poller processes
 165  */
 166 function poller_highest_priority() {
 167         $s = q("SELECT `priority` FROM `workerqueue` WHERE `executed` <= '%s' AND NOT `done` ORDER BY `priority` LIMIT 1", dbesc(NULL_DATE));
 168         if (dbm::is_result($s)) {
 169                 return $s[0]["priority"];
 170         } else {
 171                 return 0;
 172         }
 173 }
 174
 175 /**
 176  * @brief Returns if a process with the given priority is running
 177  *
 178  * @param integer $priority The priority that should be checked
 179  *
 180  * @return integer Is there a process running with that priority?
 181  */
 182 function poller_process_with_priority_active($priority) {
 183         $s = q("SELECT `id` FROM `workerqueue` WHERE `priority` <= %d AND `executed` > '%s' AND NOT `done` LIMIT 1",
 184                         intval($priority), dbesc(NULL_DATE));
 185         return dbm::is_result($s);
 186 }
 187
 188 /**
 189  * @brief Execute a worker entry
 190  *
 191  * @param array $queue Workerqueue entry
 192  *
 193  * @return boolean "true" if further processing should be stopped
 194  */
 195 function poller_execute($queue) {
 196         global $poller_db_duration, $poller_last_update;
 197
 198         $a = get_app();
 199
 200         $mypid = getmypid();
 201
 202         // Quit when in maintenance
 203         if (Config::get('system', 'maintenance', true)) {
 204                 logger("Maintenance mode - quit process ".$mypid, LOGGER_DEBUG);
 205                 return false;
 206         }
 207
 208         // Constantly check the number of parallel database processes
 209         if ($a->max_processes_reached()) {
 210                 logger("Max processes reached for process ".$mypid, LOGGER_DEBUG);
 211                 return false;
 212         }
 213
 214         // Constantly check the number of available database connections to let the frontend be accessible at any time
 215         if (poller_max_connections_reached()) {
 216                 logger("Max connection reached for process ".$mypid, LOGGER_DEBUG);
 217                 return false;
 218         }
 219
 220         $argv = json_decode($queue["parameter"]);
 221
 222         // Check for existance and validity of the include file
 223         $include = $argv[0];
 224
 225         if (!validate_include($include)) {
 226                 logger("Include file ".$argv[0]." is not valid!");
 227                 dba::delete('workerqueue', array('id' => $queue["id"]));
 228                 return true;
 229         }
 230
 231         require_once($include);
 232
 233         $funcname = str_replace(".php", "", basename($argv[0]))."_run";
 234
 235         if (function_exists($funcname)) {
 236
 237                 // We constantly update the "executed" date every minute to avoid being killed too soon
 238                 if (!isset($poller_last_update)) {
 239                         $poller_last_update = strtotime($queue["executed"]);
 240                 }
 241
 242                 $age = (time() - $poller_last_update) / 60;
 243                 $poller_last_update = time();
 244
 245                 if ($age > 1) {
 246                         $stamp = (float)microtime(true);
 247                         dba::update('workerqueue', array('executed' => datetime_convert()), array('pid' => $mypid, 'done' => false));
 248                         $poller_db_duration += (microtime(true) - $stamp);
 249                 }
 250
 251                 poller_exec_function($queue, $funcname, $argv);
 252
 253                 $stamp = (float)microtime(true);
 254                 if (dba::update('workerqueue', array('done' => true), array('id' => $queue["id"]))) {
 255                         Config::set('system', 'last_poller_execution', datetime_convert());
 256                 }
 257                 $poller_db_duration = (microtime(true) - $stamp);
 258         } else {
 259                 logger("Function ".$funcname." does not exist");
 260                 dba::delete('workerqueue', array('id' => $queue["id"]));
 261         }
 262
 263         return true;
 264 }
 265
 266 /**
 267  * @brief Execute a function from the queue
 268  *
 269  * @param array $queue Workerqueue entry
 270  * @param string $funcname name of the function
 271  * @param array $argv Array of values to be passed to the function
 272  */
 273 function poller_exec_function($queue, $funcname, $argv) {
 274         global $poller_up_start, $poller_db_duration, $poller_lock_duration;
 275
 276         $a = get_app();
 277
 278         $mypid = getmypid();
 279
 280         $argc = count($argv);
 281
 282         $new_process_id = uniqid("wrk", true);
 283
 284         logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." ".$queue["parameter"]." - Process PID: ".$new_process_id);
 285
 286         $stamp = (float)microtime(true);
 287
 288         // We use the callstack here to analyze the performance of executed worker entries.
 289         // For this reason the variables have to be initialized.
 290         if (Config::get("system", "profiler")) {
 291                 $a->performance["start"] = microtime(true);
 292                 $a->performance["database"] = 0;
 293                 $a->performance["database_write"] = 0;
 294                 $a->performance["network"] = 0;
 295                 $a->performance["file"] = 0;
 296                 $a->performance["rendering"] = 0;
 297                 $a->performance["parser"] = 0;
 298                 $a->performance["marktime"] = 0;
 299                 $a->performance["markstart"] = microtime(true);
 300                 $a->callstack = array();
 301         }
 302
 303         // For better logging create a new process id for every worker call
 304         // But preserve the old one for the worker
 305         $old_process_id = $a->process_id;
 306         $a->process_id = $new_process_id;
 307         $a->queue = $queue;
 308
 309         $up_duration = number_format(microtime(true) - $poller_up_start, 3);
 310
 311         // Reset global data to avoid interferences
 312         unset($_SESSION);
 313
 314         $funcname($argv, $argc);
 315
 316         $a->process_id = $old_process_id;
 317         unset($a->queue);
 318
 319         $duration = number_format(microtime(true) - $stamp, 3);
 320
 321         $poller_up_start = microtime(true);
 322
 323         /* With these values we can analyze how effective the worker is.
 324          * The database and rest time should be low since this is the unproductive time.
 325          * The execution time is the productive time.
 326          * By changing parameters like the maximum number of workers we can check the effectivness.
 327         */
 328         logger('DB: '.number_format($poller_db_duration, 2).
 329                 ' - Lock: '.number_format($poller_lock_duration, 2).
 330                 ' - Rest: '.number_format($up_duration - $poller_db_duration - $poller_lock_duration, 2).
 331                 ' - Execution: '.number_format($duration, 2), LOGGER_DEBUG);
 332         $poller_lock_duration = 0;
 333
 334         if ($duration > 3600) {
 335                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 1 hour (".round($duration/60, 3).")", LOGGER_DEBUG);
 336         } elseif ($duration > 600) {
 337                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 10 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 338         } elseif ($duration > 300) {
 339                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 5 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 340         } elseif ($duration > 120) {
 341                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 2 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 342         }
 343
 344         logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - done in ".$duration." seconds. Process PID: ".$new_process_id);
 345
 346         // Write down the performance values into the log
 347         if (Config::get("system", "profiler")) {
 348                 $duration = microtime(true)-$a->performance["start"];
 349
 350                 if (Config::get("rendertime", "callstack")) {
 351                         if (isset($a->callstack["database"])) {
 352                                 $o = "\nDatabase Read:\n";
 353                                 foreach ($a->callstack["database"] AS $func => $time) {
 354                                         $time = round($time, 3);
 355                                         if ($time > 0) {
 356                                                 $o .= $func.": ".$time."\n";
 357                                         }
 358                                 }
 359                         }
 360                         if (isset($a->callstack["database_write"])) {
 361                                 $o .= "\nDatabase Write:\n";
 362                                 foreach ($a->callstack["database_write"] AS $func => $time) {
 363                                         $time = round($time, 3);
 364                                         if ($time > 0) {
 365                                                 $o .= $func.": ".$time."\n";
 366                                         }
 367                                 }
 368                         }
 369                         if (isset($a->callstack["network"])) {
 370                                 $o .= "\nNetwork:\n";
 371                                 foreach ($a->callstack["network"] AS $func => $time) {
 372                                         $time = round($time, 3);
 373                                         if ($time > 0) {
 374                                                 $o .= $func.": ".$time."\n";
 375                                         }
 376                                 }
 377                         }
 378                 } else {
 379                         $o = '';
 380                 }
 381
 382                 logger("ID ".$queue["id"].": ".$funcname.": ".sprintf("DB: %s/%s, Net: %s, I/O: %s, Other: %s, Total: %s".$o,
 383                         number_format($a->performance["database"] - $a->performance["database_write"], 2),
 384                         number_format($a->performance["database_write"], 2),
 385                         number_format($a->performance["network"], 2),
 386                         number_format($a->performance["file"], 2),
 387                         number_format($duration - ($a->performance["database"] + $a->performance["network"] + $a->performance["file"]), 2),
 388                         number_format($duration, 2)),
 389                         LOGGER_DEBUG);
 390         }
 391
 392         $cooldown = Config::get("system", "worker_cooldown", 0);
 393
 394         if ($cooldown > 0) {
 395                 logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - in cooldown for ".$cooldown." seconds");
 396                 sleep($cooldown);
 397         }
 398 }
 399
 400 /**
 401  * @brief Checks if the number of database connections has reached a critical limit.
 402  *
 403  * @return bool Are more than 3/4 of the maximum connections used?
 404  */
 405 function poller_max_connections_reached() {
 406
 407         // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 408         $max = Config::get("system", "max_connections");
 409
 410         // Fetch the percentage level where the poller will get active
 411         $maxlevel = Config::get("system", "max_connections_level", 75);
 412
 413         if ($max == 0) {
 414                 // the maximum number of possible user connections can be a system variable
 415                 $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 416                 if (dbm::is_result($r)) {
 417                         $max = $r[0]["Value"];
 418                 }
 419                 // Or it can be granted. This overrides the system variable
 420                 $r = q("SHOW GRANTS");
 421                 if (dbm::is_result($r)) {
 422                         foreach ($r AS $grants) {
 423                                 $grant = array_pop($grants);
 424                                 if (stristr($grant, "GRANT USAGE ON")) {
 425                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match)) {
 426                                                 $max = $match[1];
 427                                         }
 428                                 }
 429                         }
 430                 }
 431         }
 432
 433         // If $max is set we will use the processlist to determine the current number of connections
 434         // The processlist only shows entries of the current user
 435         if ($max != 0) {
 436                 $r = q("SHOW PROCESSLIST");
 437                 if (!dbm::is_result($r)) {
 438                         return false;
 439                 }
 440                 $used = count($r);
 441
 442                 logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
 443
 444                 $level = ($used / $max) * 100;
 445
 446                 if ($level >= $maxlevel) {
 447                         logger("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
 448                         return true;
 449                 }
 450         }
 451
 452         // We will now check for the system values.
 453         // This limit could be reached although the user limits are fine.
 454         $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 455         if (!dbm::is_result($r)) {
 456                 return false;
 457         }
 458         $max = intval($r[0]["Value"]);
 459         if ($max == 0) {
 460                 return false;
 461         }
 462         $r = q("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 463         if (!dbm::is_result($r)) {
 464                 return false;
 465         }
 466         $used = intval($r[0]["Value"]);
 467         if ($used == 0) {
 468                 return false;
 469         }
 470         logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
 471
 472         $level = $used / $max * 100;
 473
 474         if ($level < $maxlevel) {
 475                 return false;
 476         }
 477         logger("Maximum level (".$level."%) of system connections reached: ".$used."/".$max);
 478         return true;
 479 }
 480
 481 /**
 482  * @brief fix the queue entry if the worker process died
 483  *
 484  */
 485 function poller_kill_stale_workers() {
 486         $entries = dba::select('workerqueue', array('id', 'pid', 'executed', 'priority', 'parameter'),
 487                                 array('`executed` > ? AND NOT `done` AND `pid` != 0', NULL_DATE),
 488                                 array('order' => array('priority', 'created')));
 489         while ($entry = dba::fetch($entries)) {
 490                 if (!posix_kill($entry["pid"], 0)) {
 491                         dba::update('workerqueue', array('executed' => NULL_DATE, 'pid' => 0),
 492                                         array('id' => $entry["id"]));
 493                 } else {
 494                         // Kill long running processes
 495                         // Check if the priority is in a valid range
 496                         if (!in_array($entry["priority"], array(PRIORITY_CRITICAL, PRIORITY_HIGH, PRIORITY_MEDIUM, PRIORITY_LOW, PRIORITY_NEGLIGIBLE))) {
 497                                 $entry["priority"] = PRIORITY_MEDIUM;
 498                         }
 499
 500                         // Define the maximum durations
 501                         $max_duration_defaults = array(PRIORITY_CRITICAL => 720, PRIORITY_HIGH => 10, PRIORITY_MEDIUM => 60, PRIORITY_LOW => 180, PRIORITY_NEGLIGIBLE => 720);
 502                         $max_duration = $max_duration_defaults[$entry["priority"]];
 503
 504                         $argv = json_decode($entry["parameter"]);
 505                         $argv[0] = basename($argv[0]);
 506
 507                         // How long is the process already running?
 508                         $duration = (time() - strtotime($entry["executed"])) / 60;
 509                         if ($duration > $max_duration) {
 510                                 logger("Worker process ".$entry["pid"]." (".implode(" ", $argv).") took more than ".$max_duration." minutes. It will be killed now.");
 511                                 posix_kill($entry["pid"], SIGTERM);
 512
 513                                 // We killed the stale process.
 514                                 // To avoid a blocking situation we reschedule the process at the beginning of the queue.
 515                                 // Additionally we are lowering the priority. (But not PRIORITY_CRITICAL)
 516                                 if ($entry["priority"] == PRIORITY_HIGH) {
 517                                         $new_priority = PRIORITY_MEDIUM;
 518                                 } elseif ($entry["priority"] == PRIORITY_MEDIUM) {
 519                                         $new_priority = PRIORITY_LOW;
 520                                 } elseif ($entry["priority"] != PRIORITY_CRITICAL) {
 521                                         $new_priority = PRIORITY_NEGLIGIBLE;
 522                                 }
 523                                 dba::update('workerqueue',
 524                                                 array('executed' => NULL_DATE, 'created' => datetime_convert(), 'priority' => $new_priority, 'pid' => 0),
 525                                                 array('id' => $entry["id"]));
 526                         } else {
 527                                 logger("Worker process ".$entry["pid"]." (".implode(" ", $argv).") now runs for ".round($duration)." of ".$max_duration." allowed minutes. That's okay.", LOGGER_DEBUG);
 528                         }
 529                 }
 530         }
 531 }
 532
 533 /**
 534  * @brief Checks if the number of active workers exceeds the given limits
 535  *
 536  * @return bool Are there too much workers running?
 537  */
 538 function poller_too_much_workers() {
 539         $queues = Config::get("system", "worker_queues", 4);
 540
 541         $maxqueues = $queues;
 542
 543         $active = poller_active_workers();
 544
 545         // Decrease the number of workers at higher load
 546         $load = current_load();
 547         if ($load) {
 548                 $maxsysload = intval(Config::get("system", "maxloadavg", 50));
 549
 550                 $maxworkers = $queues;
 551
 552                 // Some magical mathemathics to reduce the workers
 553                 $exponent = 3;
 554                 $slope = $maxworkers / pow($maxsysload, $exponent);
 555                 $queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
 556
 557                 if (Config::get('system', 'worker_debug')) {
 558                         // Create a list of queue entries grouped by their priority
 559                         $listitem = array();
 560
 561                         // Adding all processes with no workerqueue entry
 562                         $processes = dba::p("SELECT COUNT(*) AS `running` FROM `process` WHERE NOT EXISTS
 563                                                 (SELECT id FROM `workerqueue`
 564                                                 WHERE `workerqueue`.`pid` = `process`.`pid` AND NOT `done` AND `pid` != ?)", getmypid());
 565                         if ($process = dba::fetch($processes)) {
 566                                 $listitem[0] = "0:".$process["running"];
 567                         }
 568                         dba::close($processes);
 569
 570                         // Now adding all processes with workerqueue entries
 571                         $entries = dba::p("SELECT COUNT(*) AS `entries`, `priority` FROM `workerqueue` WHERE NOT `done` GROUP BY `priority`");
 572                         while ($entry = dba::fetch($entries)) {
 573                                 $processes = dba::p("SELECT COUNT(*) AS `running` FROM `process` INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done` WHERE `priority` = ?", $entry["priority"]);
 574                                 if ($process = dba::fetch($processes)) {
 575                                         $listitem[$entry["priority"]] = $entry["priority"].":".$process["running"]."/".$entry["entries"];
 576                                 }
 577                                 dba::close($processes);
 578                         }
 579                         dba::close($entries);
 580
 581                         $intervals = array(1, 10, 60);
 582                         $jobs_per_minute = array();
 583                         foreach ($intervals AS $interval) {
 584                                 $jobs = dba::p("SELECT COUNT(*) AS `jobs` FROM `workerqueue` WHERE `done` AND `executed` > UTC_TIMESTAMP() - INTERVAL ".intval($interval)." MINUTE");
 585                                 if ($job = dba::fetch($jobs)) {
 586                                         $jobs_per_minute[$interval] = number_format($job['jobs'] / $interval, 0);
 587                                 }
 588                                 dba::close($jobs);
 589                         }
 590                         $processlist = ' - jpm: '.implode('/', $jobs_per_minute).' ('.implode(', ', $listitem).')';
 591                 }
 592
 593                 $entries = poller_total_entries();
 594
 595                 if (Config::get("system", "worker_fastlane", false) && ($queues > 0) && ($entries > 0) && ($active >= $queues)) {
 596                         $top_priority = poller_highest_priority();
 597                         $high_running = poller_process_with_priority_active($top_priority);
 598
 599                         if (!$high_running && ($top_priority > PRIORITY_UNDEFINED) && ($top_priority < PRIORITY_NEGLIGIBLE)) {
 600                                 logger("There are jobs with priority ".$top_priority." waiting but none is executed. Open a fastlane.", LOGGER_DEBUG);
 601                                 $queues = $active + 1;
 602                         }
 603                 }
 604
 605                 logger("Load: ".$load."/".$maxsysload." - processes: ".$active."/".$entries.$processlist." - maximum: ".$queues."/".$maxqueues, LOGGER_DEBUG);
 606
 607                 // Are there fewer workers running as possible? Then fork a new one.
 608                 if (!Config::get("system", "worker_dont_fork") && ($queues > ($active + 1)) && ($entries > 1)) {
 609                         logger("Active workers: ".$active."/".$queues." Fork a new worker.", LOGGER_DEBUG);
 610                         $args = array("include/poller.php", "no_cron");
 611                         get_app()->proc_run($args);
 612                 }
 613         }
 614
 615         return $active >= $queues;
 616 }
 617
 618 /**
 619  * @brief Returns the number of active poller processes
 620  *
 621  * @return integer Number of active poller processes
 622  */
 623 function poller_active_workers() {
 624         $workers = q("SELECT COUNT(*) AS `processes` FROM `process` WHERE `command` = 'poller.php'");
 625
 626         return $workers[0]["processes"];
 627 }
 628
 629 /**
 630  * @brief Check if we should pass some slow processes
 631  *
 632  * When the active processes of the highest priority are using more than 2/3
 633  * of all processes, we let pass slower processes.
 634  *
 635  * @param string $highest_priority Returns the currently highest priority
 636  * @return bool We let pass a slower process than $highest_priority
 637  */
 638 function poller_passing_slow(&$highest_priority) {
 639
 640         $highest_priority = 0;
 641
 642         $r = q("SELECT `priority`
 643                 FROM `process`
 644                 INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done`");
 645
 646         // No active processes at all? Fine
 647         if (!dbm::is_result($r)) {
 648                 return false;
 649         }
 650         $priorities = array();
 651         foreach ($r AS $line) {
 652                 $priorities[] = $line["priority"];
 653         }
 654         // Should not happen
 655         if (count($priorities) == 0) {
 656                 return false;
 657         }
 658         $highest_priority = min($priorities);
 659
 660         // The highest process is already the slowest one?
 661         // Then we quit
 662         if ($highest_priority == PRIORITY_NEGLIGIBLE) {
 663                 return false;
 664         }
 665         $high = 0;
 666         foreach ($priorities AS $priority) {
 667                 if ($priority == $highest_priority) {
 668                         ++$high;
 669                 }
 670         }
 671         logger("Highest priority: ".$highest_priority." Total processes: ".count($priorities)." Count high priority processes: ".$high, LOGGER_DEBUG);
 672         $passing_slow = (($high/count($priorities)) > (2/3));
 673
 674         if ($passing_slow) {
 675                 logger("Passing slower processes than priority ".$highest_priority, LOGGER_DEBUG);
 676         }
 677         return $passing_slow;
 678 }
 679
 680 /**
 681  * @brief Find and claim the next worker process for us
 682  *
 683  * @param boolean $passing_slow Returns if we had passed low priority processes
 684  * @return boolean Have we found something?
 685  */
 686 function find_worker_processes(&$passing_slow) {
 687
 688         $mypid = getmypid();
 689
 690         // Check if we should pass some low priority process
 691         $highest_priority = 0;
 692         $found = false;
 693         $passing_slow = false;
 694
 695         // The higher the number of parallel workers, the more we prefetch to prevent concurring access
 696         // We decrease the limit with the number of entries left in the queue
 697         $worker_queues = Config::get("system", "worker_queues", 4);
 698         $queue_length = Config::get('system', 'worker_fetch_limit', 1);
 699         $lower_job_limit = $worker_queues * $queue_length * 2;
 700         $jobs = poller_total_entries();
 701
 702         // Now do some magic
 703         $exponent = 2;
 704         $slope = $queue_length / pow($lower_job_limit, $exponent);
 705         $limit = min($queue_length, ceil($slope * pow($jobs, $exponent)));
 706
 707         logger('Total: '.$jobs.' - Maximum: '.$queue_length.' - jobs per queue: '.$limit, LOGGER_DEBUG);
 708
 709         if (poller_passing_slow($highest_priority)) {
 710                 // Are there waiting processes with a higher priority than the currently highest?
 711                 $result = dba::select('workerqueue', array('id'), array("`executed` <= ? AND `priority` < ? AND NOT `done`", NULL_DATE, $highest_priority),
 712                                 array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true));
 713
 714                 while ($id = dba::fetch($result)) {
 715                         $ids[] = $id["id"];
 716                 }
 717                 dba::close($result);
 718
 719                 $found = (count($ids) > 0);
 720
 721                 if (!$found) {
 722                         // Give slower processes some processing time
 723                         $result = dba::select('workerqueue', array('id'), array("`executed` <= ? AND `priority` > ? AND NOT `done`", NULL_DATE, $highest_priority),
 724                                         array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true));
 725
 726                         while ($id = dba::fetch($result)) {
 727                                 $ids[] = $id["id"];
 728                         }
 729                         dba::close($result);
 730
 731                         $found = (count($ids) > 0);
 732                         $passing_slow = $found;
 733                 }
 734         }
 735
 736         // If there is no result (or we shouldn't pass lower processes) we check without priority limit
 737         if (!$found) {
 738                 $result = dba::select('workerqueue', array('id'), array("`executed` <= ? AND NOT `done`", NULL_DATE),
 739                                 array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true));
 740
 741                 while ($id = dba::fetch($result)) {
 742                         $ids[] = $id["id"];
 743                 }
 744                 dba::close($result);
 745
 746                 $found = (count($ids) > 0);
 747         }
 748
 749         if ($found) {
 750                 $condition = "`id` IN (".substr(str_repeat("?, ", count($ids)), 0, -2).") AND `pid` = 0 AND NOT `done`";
 751                 array_unshift($ids, $condition);
 752                 dba::update('workerqueue', array('executed' => datetime_convert(), 'pid' => $mypid), $ids);
 753         }
 754
 755         return $found;
 756 }
 757
 758 /**
 759  * @brief Returns the next worker process
 760  *
 761  * @param boolean $passing_slow Returns if we had passed low priority processes
 762  * @return string SQL statement
 763  */
 764 function poller_worker_process(&$passing_slow) {
 765         global $poller_db_duration, $poller_lock_duration;
 766
 767         $stamp = (float)microtime(true);
 768
 769         // There can already be jobs for us in the queue.
 770         $r = q("SELECT * FROM `workerqueue` WHERE `pid` = %d AND NOT `done`", intval(getmypid()));
 771         if (dbm::is_result($r)) {
 772                 $poller_db_duration += (microtime(true) - $stamp);
 773                 return $r;
 774         }
 775
 776         $stamp = (float)microtime(true);
 777         if (!Lock::set('poller_worker_process')) {
 778                 return false;
 779         }
 780         $poller_lock_duration = (microtime(true) - $stamp);
 781
 782         $stamp = (float)microtime(true);
 783         $found = find_worker_processes($passing_slow);
 784         $poller_db_duration += (microtime(true) - $stamp);
 785
 786         Lock::remove('poller_worker_process');
 787
 788         if ($found) {
 789                 $r = q("SELECT * FROM `workerqueue` WHERE `pid` = %d AND NOT `done`", intval(getmypid()));
 790         }
 791         return $r;
 792 }
 793
 794 /**
 795  * @brief Removes a workerqueue entry from the current process
 796  */
 797 function poller_unclaim_process() {
 798         $mypid = getmypid();
 799
 800         dba::update('workerqueue', array('executed' => NULL_DATE, 'pid' => 0), array('pid' => $mypid, 'done' => false));
 801 }
 802
 803 /**
 804  * @brief Call the front end worker
 805  */
 806 function call_worker() {
 807         if (!Config::get("system", "frontend_worker")) {
 808                 return;
 809         }
 810
 811         $url = System::baseUrl()."/worker";
 812         fetch_url($url, false, $redirects, 1);
 813 }
 814
 815 /**
 816  * @brief Call the front end worker if there aren't any active
 817  */
 818 function call_worker_if_idle() {
 819         if (!Config::get("system", "frontend_worker")) {
 820                 return;
 821         }
 822
 823         // Do we have "proc_open"? Then we can fork the poller
 824         if (function_exists("proc_open")) {
 825                 // When was the last time that we called the worker?
 826                 // Less than one minute? Then we quit
 827                 if ((time() - Config::get("system", "worker_started")) < 60) {
 828                         return;
 829                 }
 830
 831                 set_config("system", "worker_started", time());
 832
 833                 // Do we have enough running workers? Then we quit here.
 834                 if (poller_too_much_workers()) {
 835                         // Cleaning dead processes
 836                         poller_kill_stale_workers();
 837                         get_app()->remove_inactive_processes();
 838
 839                         return;
 840                 }
 841
 842                 poller_run_cron();
 843
 844                 logger('Call poller', LOGGER_DEBUG);
 845
 846                 $args = array("include/poller.php", "no_cron");
 847                 get_app()->proc_run($args);
 848                 return;
 849         }
 850
 851         // We cannot execute background processes.
 852         // We now run the processes from the frontend.
 853         // This won't work with long running processes.
 854         poller_run_cron();
 855
 856         clear_worker_processes();
 857
 858         $workers = q("SELECT COUNT(*) AS `processes` FROM `process` WHERE `command` = 'worker.php'");
 859
 860         if ($workers[0]["processes"] == 0) {
 861                 call_worker();
 862         }
 863 }
 864
 865 /**
 866  * @brief Removes long running worker processes
 867  */
 868 function clear_worker_processes() {
 869         $timeout = Config::get("system", "frontend_worker_timeout", 10);
 870
 871         /// @todo We should clean up the corresponding workerqueue entries as well
 872         q("DELETE FROM `process` WHERE `created` < '%s' AND `command` = 'worker.php'",
 873                 dbesc(datetime_convert('UTC','UTC',"now - ".$timeout." minutes")));
 874 }
 875
 876 /**
 877  * @brief Runs the cron processes
 878  */
 879 function poller_run_cron() {
 880         logger('Add cron entries', LOGGER_DEBUG);
 881
 882         // Check for spooled items
 883         proc_run(PRIORITY_HIGH, "include/spool_post.php");
 884
 885         // Run the cron job that calls all other jobs
 886         proc_run(PRIORITY_MEDIUM, "include/cron.php");
 887
 888         // Run the cronhooks job separately from cron for being able to use a different timing
 889         proc_run(PRIORITY_MEDIUM, "include/cronhooks.php");
 890
 891         // Cleaning dead processes
 892         poller_kill_stale_workers();
 893 }
 894
 895 if (array_search(__file__,get_included_files())===0) {
 896         poller_run($_SERVER["argv"],$_SERVER["argc"]);
 897
 898         poller_unclaim_process();
 899
 900         get_app()->end_process();
 901
 902         killme();
 903 }