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         $poller_up_start = microtime(true);
  25
  26         if (empty($a)) {
  27                 $a = new App(dirname(__DIR__));
  28         }
  29
  30         require_once ".htconfig.php";
  31         require_once "include/dba.php";
  32         dba::connect($db_host, $db_user, $db_pass, $db_data);
  33         unset($db_host, $db_user, $db_pass, $db_data);
  34
  35         Config::load();
  36
  37         // Check the database structure and possibly fixes it
  38         check_db(true);
  39
  40         // Quit when in maintenance
  41         if (Config::get('system', 'maintenance', true)) {
  42                 return;
  43         }
  44
  45         $a->set_baseurl(Config::get('system', 'url'));
  46
  47         load_hooks();
  48
  49         // At first check the maximum load. We shouldn't continue with a high load
  50         if ($a->maxload_reached()) {
  51                 logger('Pre check: maximum load reached, quitting.', LOGGER_DEBUG);
  52                 return;
  53         }
  54
  55         // We now start the process. This is done after the load check since this could increase the load.
  56         $a->start_process();
  57
  58         // Kill stale processes every 5 minutes
  59         $last_cleanup = Config::get('system', 'poller_last_cleaned', 0);
  60         if (time() > ($last_cleanup + 300)) {
  61                 Config::set('system', 'poller_last_cleaned', time());
  62                 poller_kill_stale_workers();
  63         }
  64
  65         // Count active workers and compare them with a maximum value that depends on the load
  66         if (poller_too_much_workers()) {
  67                 logger('Pre check: Active worker limit reached, quitting.', LOGGER_DEBUG);
  68                 return;
  69         }
  70
  71         // Do we have too few memory?
  72         if ($a->min_memory_reached()) {
  73                 logger('Pre check: Memory limit reached, quitting.', LOGGER_DEBUG);
  74                 return;
  75         }
  76
  77         // Possibly there are too much database connections
  78         if (poller_max_connections_reached()) {
  79                 logger('Pre check: maximum connections reached, quitting.', LOGGER_DEBUG);
  80                 return;
  81         }
  82
  83         // Possibly there are too much database processes that block the system
  84         if ($a->max_processes_reached()) {
  85                 logger('Pre check: maximum processes reached, quitting.', LOGGER_DEBUG);
  86                 return;
  87         }
  88
  89         // Now we start additional cron processes if we should do so
  90         if (($argc <= 1) || ($argv[1] != "no_cron")) {
  91                 poller_run_cron();
  92         }
  93
  94         $starttime = time();
  95
  96         // We fetch the next queue entry that is about to be executed
  97         while ($r = poller_worker_process($passing_slow)) {
  98
  99                 // When we are processing jobs with a lower priority, we don't refetch new jobs
 100                 // Otherwise fast jobs could wait behind slow ones and could be blocked.
 101                 $refetched = $passing_slow;
 102
 103                 foreach ($r AS $entry) {
 104                         // Assure that the priority is an integer value
 105                         $entry['priority'] = (int)$entry['priority'];
 106
 107                         // The work will be done
 108                         if (!poller_execute($entry)) {
 109                                 logger('Process execution failed, quitting.', LOGGER_DEBUG);
 110                                 return;
 111                         }
 112
 113                         // If possible we will fetch new jobs for this worker
 114                         if (!$refetched && Lock::set('poller_worker_process', 0)) {
 115                                 $stamp = (float)microtime(true);
 116                                 $refetched = find_worker_processes($passing_slow);
 117                                 $poller_db_duration += (microtime(true) - $stamp);
 118                                 Lock::remove('poller_worker_process');
 119                         }
 120                 }
 121
 122                 // To avoid the quitting of multiple pollers only one poller at a time will execute the check
 123                 if (Lock::set('poller_worker', 0)) {
 124                         $stamp = (float)microtime(true);
 125                         // Count active workers and compare them with a maximum value that depends on the load
 126                         if (poller_too_much_workers()) {
 127                                 logger('Active worker limit reached, quitting.', LOGGER_DEBUG);
 128                                 return;
 129                         }
 130
 131                         // Check free memory
 132                         if ($a->min_memory_reached()) {
 133                                 logger('Memory limit reached, quitting.', LOGGER_DEBUG);
 134                                 return;
 135                         }
 136                         Lock::remove('poller_worker');
 137                         $poller_db_duration += (microtime(true) - $stamp);
 138                 }
 139
 140                 // Quit the poller once every 5 minutes
 141                 if (time() > ($starttime + 300)) {
 142                         logger('Process lifetime reached, quitting.', LOGGER_DEBUG);
 143                         return;
 144                 }
 145         }
 146         logger("Couldn't select a workerqueue entry, quitting.", LOGGER_DEBUG);
 147 }
 148
 149 /**
 150  * @brief Returns the number of non executed entries in the worker queue
 151  *
 152  * @return integer Number of non executed entries in the worker queue
 153  */
 154 function poller_total_entries() {
 155         $s = q("SELECT COUNT(*) AS `total` FROM `workerqueue` WHERE `executed` <= '%s' AND NOT `done`", dbesc(NULL_DATE));
 156         if (dbm::is_result($s)) {
 157                 return $s[0]["total"];
 158         } else {
 159                 return 0;
 160         }
 161 }
 162
 163 /**
 164  * @brief Returns the highest priority in the worker queue that isn't executed
 165  *
 166  * @return integer Number of active poller processes
 167  */
 168 function poller_highest_priority() {
 169         $s = q("SELECT `priority` FROM `workerqueue` WHERE `executed` <= '%s' AND NOT `done` ORDER BY `priority` LIMIT 1", dbesc(NULL_DATE));
 170         if (dbm::is_result($s)) {
 171                 return $s[0]["priority"];
 172         } else {
 173                 return 0;
 174         }
 175 }
 176
 177 /**
 178  * @brief Returns if a process with the given priority is running
 179  *
 180  * @param integer $priority The priority that should be checked
 181  *
 182  * @return integer Is there a process running with that priority?
 183  */
 184 function poller_process_with_priority_active($priority) {
 185         $s = q("SELECT `id` FROM `workerqueue` WHERE `priority` <= %d AND `executed` > '%s' AND NOT `done` LIMIT 1",
 186                         intval($priority), dbesc(NULL_DATE));
 187         return dbm::is_result($s);
 188 }
 189
 190 /**
 191  * @brief Execute a worker entry
 192  *
 193  * @param array $queue Workerqueue entry
 194  *
 195  * @return boolean "true" if further processing should be stopped
 196  */
 197 function poller_execute($queue) {
 198         global $poller_db_duration, $poller_last_update;
 199
 200         $a = get_app();
 201
 202         $mypid = getmypid();
 203
 204         // Quit when in maintenance
 205         if (Config::get('system', 'maintenance', true)) {
 206                 logger("Maintenance mode - quit process ".$mypid, LOGGER_DEBUG);
 207                 return false;
 208         }
 209
 210         // Constantly check the number of parallel database processes
 211         if ($a->max_processes_reached()) {
 212                 logger("Max processes reached for process ".$mypid, LOGGER_DEBUG);
 213                 return false;
 214         }
 215
 216         // Constantly check the number of available database connections to let the frontend be accessible at any time
 217         if (poller_max_connections_reached()) {
 218                 logger("Max connection reached for process ".$mypid, LOGGER_DEBUG);
 219                 return false;
 220         }
 221
 222         $argv = json_decode($queue["parameter"]);
 223
 224         // Check for existance and validity of the include file
 225         $include = $argv[0];
 226
 227         if (!validate_include($include)) {
 228                 logger("Include file ".$argv[0]." is not valid!");
 229                 dba::delete('workerqueue', array('id' => $queue["id"]));
 230                 return true;
 231         }
 232
 233         require_once($include);
 234
 235         $funcname = str_replace(".php", "", basename($argv[0]))."_run";
 236
 237         if (function_exists($funcname)) {
 238
 239                 // We constantly update the "executed" date every minute to avoid being killed too soon
 240                 if (!isset($poller_last_update)) {
 241                         $poller_last_update = strtotime($queue["executed"]);
 242                 }
 243
 244                 $age = (time() - $poller_last_update) / 60;
 245                 $poller_last_update = time();
 246
 247                 if ($age > 1) {
 248                         $stamp = (float)microtime(true);
 249                         dba::update('workerqueue', array('executed' => datetime_convert()), array('pid' => $mypid, 'done' => false));
 250                         $poller_db_duration += (microtime(true) - $stamp);
 251                 }
 252
 253                 poller_exec_function($queue, $funcname, $argv);
 254
 255                 $stamp = (float)microtime(true);
 256                 if (dba::update('workerqueue', array('done' => true), array('id' => $queue["id"]))) {
 257                         Config::set('system', 'last_poller_execution', datetime_convert());
 258                 }
 259                 $poller_db_duration = (microtime(true) - $stamp);
 260         } else {
 261                 logger("Function ".$funcname." does not exist");
 262                 dba::delete('workerqueue', array('id' => $queue["id"]));
 263         }
 264
 265         return true;
 266 }
 267
 268 /**
 269  * @brief Execute a function from the queue
 270  *
 271  * @param array $queue Workerqueue entry
 272  * @param string $funcname name of the function
 273  * @param array $argv Array of values to be passed to the function
 274  */
 275 function poller_exec_function($queue, $funcname, $argv) {
 276         global $poller_up_start, $poller_db_duration, $poller_lock_duration;
 277
 278         $a = get_app();
 279
 280         $mypid = getmypid();
 281
 282         $argc = count($argv);
 283
 284         $new_process_id = uniqid("wrk", true);
 285
 286         logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." ".$queue["parameter"]." - Process PID: ".$new_process_id);
 287
 288         $stamp = (float)microtime(true);
 289
 290         // We use the callstack here to analyze the performance of executed worker entries.
 291         // For this reason the variables have to be initialized.
 292         if (Config::get("system", "profiler")) {
 293                 $a->performance["start"] = microtime(true);
 294                 $a->performance["database"] = 0;
 295                 $a->performance["database_write"] = 0;
 296                 $a->performance["network"] = 0;
 297                 $a->performance["file"] = 0;
 298                 $a->performance["rendering"] = 0;
 299                 $a->performance["parser"] = 0;
 300                 $a->performance["marktime"] = 0;
 301                 $a->performance["markstart"] = microtime(true);
 302                 $a->callstack = array();
 303         }
 304
 305         // For better logging create a new process id for every worker call
 306         // But preserve the old one for the worker
 307         $old_process_id = $a->process_id;
 308         $a->process_id = $new_process_id;
 309         $a->queue = $queue;
 310
 311         $up_duration = number_format(microtime(true) - $poller_up_start, 3);
 312
 313         // Reset global data to avoid interferences
 314         unset($_SESSION);
 315
 316         $funcname($argv, $argc);
 317
 318         $a->process_id = $old_process_id;
 319         unset($a->queue);
 320
 321         $duration = number_format(microtime(true) - $stamp, 3);
 322
 323         $poller_up_start = microtime(true);
 324
 325         /* With these values we can analyze how effective the worker is.
 326          * The database and rest time should be low since this is the unproductive time.
 327          * The execution time is the productive time.
 328          * By changing parameters like the maximum number of workers we can check the effectivness.
 329         */
 330         logger('DB: '.number_format($poller_db_duration, 2).
 331                 ' - Lock: '.number_format($poller_lock_duration, 2).
 332                 ' - Rest: '.number_format($up_duration - $poller_db_duration - $poller_lock_duration, 2).
 333                 ' - Execution: '.number_format($duration, 2), LOGGER_DEBUG);
 334         $poller_lock_duration = 0;
 335
 336         if ($duration > 3600) {
 337                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 1 hour (".round($duration/60, 3).")", LOGGER_DEBUG);
 338         } elseif ($duration > 600) {
 339                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 10 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 340         } elseif ($duration > 300) {
 341                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 5 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 342         } elseif ($duration > 120) {
 343                 logger("Prio ".$queue["priority"].": ".$queue["parameter"]." - longer than 2 minutes (".round($duration/60, 3).")", LOGGER_DEBUG);
 344         }
 345
 346         logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - done in ".$duration." seconds. Process PID: ".$new_process_id);
 347
 348         // Write down the performance values into the log
 349         if (Config::get("system", "profiler")) {
 350                 $duration = microtime(true)-$a->performance["start"];
 351
 352                 if (Config::get("rendertime", "callstack")) {
 353                         if (isset($a->callstack["database"])) {
 354                                 $o = "\nDatabase Read:\n";
 355                                 foreach ($a->callstack["database"] AS $func => $time) {
 356                                         $time = round($time, 3);
 357                                         if ($time > 0) {
 358                                                 $o .= $func.": ".$time."\n";
 359                                         }
 360                                 }
 361                         }
 362                         if (isset($a->callstack["database_write"])) {
 363                                 $o .= "\nDatabase Write:\n";
 364                                 foreach ($a->callstack["database_write"] AS $func => $time) {
 365                                         $time = round($time, 3);
 366                                         if ($time > 0) {
 367                                                 $o .= $func.": ".$time."\n";
 368                                         }
 369                                 }
 370                         }
 371                         if (isset($a->callstack["network"])) {
 372                                 $o .= "\nNetwork:\n";
 373                                 foreach ($a->callstack["network"] AS $func => $time) {
 374                                         $time = round($time, 3);
 375                                         if ($time > 0) {
 376                                                 $o .= $func.": ".$time."\n";
 377                                         }
 378                                 }
 379                         }
 380                 } else {
 381                         $o = '';
 382                 }
 383
 384                 logger("ID ".$queue["id"].": ".$funcname.": ".sprintf("DB: %s/%s, Net: %s, I/O: %s, Other: %s, Total: %s".$o,
 385                         number_format($a->performance["database"] - $a->performance["database_write"], 2),
 386                         number_format($a->performance["database_write"], 2),
 387                         number_format($a->performance["network"], 2),
 388                         number_format($a->performance["file"], 2),
 389                         number_format($duration - ($a->performance["database"] + $a->performance["network"] + $a->performance["file"]), 2),
 390                         number_format($duration, 2)),
 391                         LOGGER_DEBUG);
 392         }
 393
 394         $cooldown = Config::get("system", "worker_cooldown", 0);
 395
 396         if ($cooldown > 0) {
 397                 logger("Process ".$mypid." - Prio ".$queue["priority"]." - ID ".$queue["id"].": ".$funcname." - in cooldown for ".$cooldown." seconds");
 398                 sleep($cooldown);
 399         }
 400 }
 401
 402 /**
 403  * @brief Checks if the number of database connections has reached a critical limit.
 404  *
 405  * @return bool Are more than 3/4 of the maximum connections used?
 406  */
 407 function poller_max_connections_reached() {
 408
 409         // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
 410         $max = Config::get("system", "max_connections");
 411
 412         // Fetch the percentage level where the poller will get active
 413         $maxlevel = Config::get("system", "max_connections_level", 75);
 414
 415         if ($max == 0) {
 416                 // the maximum number of possible user connections can be a system variable
 417                 $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
 418                 if (dbm::is_result($r)) {
 419                         $max = $r[0]["Value"];
 420                 }
 421                 // Or it can be granted. This overrides the system variable
 422                 $r = q("SHOW GRANTS");
 423                 if (dbm::is_result($r)) {
 424                         foreach ($r AS $grants) {
 425                                 $grant = array_pop($grants);
 426                                 if (stristr($grant, "GRANT USAGE ON")) {
 427                                         if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match)) {
 428                                                 $max = $match[1];
 429                                         }
 430                                 }
 431                         }
 432                 }
 433         }
 434
 435         // If $max is set we will use the processlist to determine the current number of connections
 436         // The processlist only shows entries of the current user
 437         if ($max != 0) {
 438                 $r = q("SHOW PROCESSLIST");
 439                 if (!dbm::is_result($r)) {
 440                         return false;
 441                 }
 442                 $used = count($r);
 443
 444                 logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
 445
 446                 $level = ($used / $max) * 100;
 447
 448                 if ($level >= $maxlevel) {
 449                         logger("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
 450                         return true;
 451                 }
 452         }
 453
 454         // We will now check for the system values.
 455         // This limit could be reached although the user limits are fine.
 456         $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
 457         if (!dbm::is_result($r)) {
 458                 return false;
 459         }
 460         $max = intval($r[0]["Value"]);
 461         if ($max == 0) {
 462                 return false;
 463         }
 464         $r = q("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
 465         if (!dbm::is_result($r)) {
 466                 return false;
 467         }
 468         $used = intval($r[0]["Value"]);
 469         if ($used == 0) {
 470                 return false;
 471         }
 472         logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
 473
 474         $level = $used / $max * 100;
 475
 476         if ($level < $maxlevel) {
 477                 return false;
 478         }
 479         logger("Maximum level (".$level."%) of system connections reached: ".$used."/".$max);
 480         return true;
 481 }
 482
 483 /**
 484  * @brief fix the queue entry if the worker process died
 485  *
 486  */
 487 function poller_kill_stale_workers() {
 488         $entries = dba::select('workerqueue', array('id', 'pid', 'executed', 'priority', 'parameter'),
 489                                 array('`executed` > ? AND NOT `done` AND `pid` != 0', NULL_DATE),
 490                                 array('order' => array('priority', 'created')));
 491         while ($entry = dba::fetch($entries)) {
 492                 if (!posix_kill($entry["pid"], 0)) {
 493                         dba::update('workerqueue', array('executed' => NULL_DATE, 'pid' => 0),
 494                                         array('id' => $entry["id"]));
 495                 } else {
 496                         // Kill long running processes
 497                         // Check if the priority is in a valid range
 498                         if (!in_array($entry["priority"], array(PRIORITY_CRITICAL, PRIORITY_HIGH, PRIORITY_MEDIUM, PRIORITY_LOW, PRIORITY_NEGLIGIBLE))) {
 499                                 $entry["priority"] = PRIORITY_MEDIUM;
 500                         }
 501
 502                         // Define the maximum durations
 503                         $max_duration_defaults = array(PRIORITY_CRITICAL => 720, PRIORITY_HIGH => 10, PRIORITY_MEDIUM => 60, PRIORITY_LOW => 180, PRIORITY_NEGLIGIBLE => 720);
 504                         $max_duration = $max_duration_defaults[$entry["priority"]];
 505
 506                         $argv = json_decode($entry["parameter"]);
 507                         $argv[0] = basename($argv[0]);
 508
 509                         // How long is the process already running?
 510                         $duration = (time() - strtotime($entry["executed"])) / 60;
 511                         if ($duration > $max_duration) {
 512                                 logger("Worker process ".$entry["pid"]." (".implode(" ", $argv).") took more than ".$max_duration." minutes. It will be killed now.");
 513                                 posix_kill($entry["pid"], SIGTERM);
 514
 515                                 // We killed the stale process.
 516                                 // To avoid a blocking situation we reschedule the process at the beginning of the queue.
 517                                 // Additionally we are lowering the priority. (But not PRIORITY_CRITICAL)
 518                                 if ($entry["priority"] == PRIORITY_HIGH) {
 519                                         $new_priority = PRIORITY_MEDIUM;
 520                                 } elseif ($entry["priority"] == PRIORITY_MEDIUM) {
 521                                         $new_priority = PRIORITY_LOW;
 522                                 } elseif ($entry["priority"] != PRIORITY_CRITICAL) {
 523                                         $new_priority = PRIORITY_NEGLIGIBLE;
 524                                 }
 525                                 dba::update('workerqueue',
 526                                                 array('executed' => NULL_DATE, 'created' => datetime_convert(), 'priority' => $new_priority, 'pid' => 0),
 527                                                 array('id' => $entry["id"]));
 528                         } else {
 529                                 logger("Worker process ".$entry["pid"]." (".implode(" ", $argv).") now runs for ".round($duration)." of ".$max_duration." allowed minutes. That's okay.", LOGGER_DEBUG);
 530                         }
 531                 }
 532         }
 533 }
 534
 535 /**
 536  * @brief Checks if the number of active workers exceeds the given limits
 537  *
 538  * @return bool Are there too much workers running?
 539  */
 540 function poller_too_much_workers() {
 541         $queues = Config::get("system", "worker_queues", 4);
 542
 543         $maxqueues = $queues;
 544
 545         $active = poller_active_workers();
 546
 547         // Decrease the number of workers at higher load
 548         $load = current_load();
 549         if ($load) {
 550                 $maxsysload = intval(Config::get("system", "maxloadavg", 50));
 551
 552                 $maxworkers = $queues;
 553
 554                 // Some magical mathemathics to reduce the workers
 555                 $exponent = 3;
 556                 $slope = $maxworkers / pow($maxsysload, $exponent);
 557                 $queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
 558
 559                 if (Config::get('system', 'worker_debug')) {
 560                         // Create a list of queue entries grouped by their priority
 561                         $listitem = array();
 562
 563                         // Adding all processes with no workerqueue entry
 564                         $processes = dba::p("SELECT COUNT(*) AS `running` FROM `process` WHERE NOT EXISTS
 565                                                 (SELECT id FROM `workerqueue`
 566                                                 WHERE `workerqueue`.`pid` = `process`.`pid` AND NOT `done` AND `pid` != ?)", getmypid());
 567                         if ($process = dba::fetch($processes)) {
 568                                 $listitem[0] = "0:".$process["running"];
 569                         }
 570                         dba::close($processes);
 571
 572                         // Now adding all processes with workerqueue entries
 573                         $entries = dba::p("SELECT COUNT(*) AS `entries`, `priority` FROM `workerqueue` WHERE NOT `done` GROUP BY `priority`");
 574                         while ($entry = dba::fetch($entries)) {
 575                                 $processes = dba::p("SELECT COUNT(*) AS `running` FROM `process` INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done` WHERE `priority` = ?", $entry["priority"]);
 576                                 if ($process = dba::fetch($processes)) {
 577                                         $listitem[$entry["priority"]] = $entry["priority"].":".$process["running"]."/".$entry["entries"];
 578                                 }
 579                                 dba::close($processes);
 580                         }
 581                         dba::close($entries);
 582
 583                         $intervals = array(1, 10, 60);
 584                         $jobs_per_minute = array();
 585                         foreach ($intervals AS $interval) {
 586                                 $jobs = dba::p("SELECT COUNT(*) AS `jobs` FROM `workerqueue` WHERE `done` AND `executed` > UTC_TIMESTAMP() - INTERVAL ".intval($interval)." MINUTE");
 587                                 if ($job = dba::fetch($jobs)) {
 588                                         $jobs_per_minute[$interval] = number_format($job['jobs'] / $interval, 0);
 589                                 }
 590                                 dba::close($jobs);
 591                         }
 592                         $processlist = ' - jpm: '.implode('/', $jobs_per_minute).' ('.implode(', ', $listitem).')';
 593                 }
 594
 595                 $entries = poller_total_entries();
 596
 597                 if (Config::get("system", "worker_fastlane", false) && ($queues > 0) && ($entries > 0) && ($active >= $queues)) {
 598                         $top_priority = poller_highest_priority();
 599                         $high_running = poller_process_with_priority_active($top_priority);
 600
 601                         if (!$high_running && ($top_priority > PRIORITY_UNDEFINED) && ($top_priority < PRIORITY_NEGLIGIBLE)) {
 602                                 logger("There are jobs with priority ".$top_priority." waiting but none is executed. Open a fastlane.", LOGGER_DEBUG);
 603                                 $queues = $active + 1;
 604                         }
 605                 }
 606
 607                 logger("Load: ".$load."/".$maxsysload." - processes: ".$active."/".$entries.$processlist." - maximum: ".$queues."/".$maxqueues, LOGGER_DEBUG);
 608
 609                 // Are there fewer workers running as possible? Then fork a new one.
 610                 if (!Config::get("system", "worker_dont_fork") && ($queues > ($active + 1)) && ($entries > 1)) {
 611                         logger("Active workers: ".$active."/".$queues." Fork a new worker.", LOGGER_DEBUG);
 612                         $args = array("include/poller.php", "no_cron");
 613                         get_app()->proc_run($args);
 614                 }
 615         }
 616
 617         return $active >= $queues;
 618 }
 619
 620 /**
 621  * @brief Returns the number of active poller processes
 622  *
 623  * @return integer Number of active poller processes
 624  */
 625 function poller_active_workers() {
 626         $workers = q("SELECT COUNT(*) AS `processes` FROM `process` WHERE `command` = 'poller.php'");
 627
 628         return $workers[0]["processes"];
 629 }
 630
 631 /**
 632  * @brief Check if we should pass some slow processes
 633  *
 634  * When the active processes of the highest priority are using more than 2/3
 635  * of all processes, we let pass slower processes.
 636  *
 637  * @param string $highest_priority Returns the currently highest priority
 638  * @return bool We let pass a slower process than $highest_priority
 639  */
 640 function poller_passing_slow(&$highest_priority) {
 641
 642         $highest_priority = 0;
 643
 644         $r = q("SELECT `priority`
 645                 FROM `process`
 646                 INNER JOIN `workerqueue` ON `workerqueue`.`pid` = `process`.`pid` AND NOT `done`");
 647
 648         // No active processes at all? Fine
 649         if (!dbm::is_result($r)) {
 650                 return false;
 651         }
 652         $priorities = array();
 653         foreach ($r AS $line) {
 654                 $priorities[] = $line["priority"];
 655         }
 656         // Should not happen
 657         if (count($priorities) == 0) {
 658                 return false;
 659         }
 660         $highest_priority = min($priorities);
 661
 662         // The highest process is already the slowest one?
 663         // Then we quit
 664         if ($highest_priority == PRIORITY_NEGLIGIBLE) {
 665                 return false;
 666         }
 667         $high = 0;
 668         foreach ($priorities AS $priority) {
 669                 if ($priority == $highest_priority) {
 670                         ++$high;
 671                 }
 672         }
 673         logger("Highest priority: ".$highest_priority." Total processes: ".count($priorities)." Count high priority processes: ".$high, LOGGER_DEBUG);
 674         $passing_slow = (($high/count($priorities)) > (2/3));
 675
 676         if ($passing_slow) {
 677                 logger("Passing slower processes than priority ".$highest_priority, LOGGER_DEBUG);
 678         }
 679         return $passing_slow;
 680 }
 681
 682 /**
 683  * @brief Find and claim the next worker process for us
 684  *
 685  * @param boolean $passing_slow Returns if we had passed low priority processes
 686  * @return boolean Have we found something?
 687  */
 688 function find_worker_processes(&$passing_slow) {
 689
 690         $mypid = getmypid();
 691
 692         // Check if we should pass some low priority process
 693         $highest_priority = 0;
 694         $found = false;
 695         $passing_slow = false;
 696
 697         // The higher the number of parallel workers, the more we prefetch to prevent concurring access
 698         // We decrease the limit with the number of entries left in the queue
 699         $worker_queues = Config::get("system", "worker_queues", 4);
 700         $queue_length = Config::get('system', 'worker_fetch_limit', 1);
 701         $lower_job_limit = $worker_queues * $queue_length * 2;
 702         $jobs = poller_total_entries();
 703
 704         // Now do some magic
 705         $exponent = 2;
 706         $slope = $queue_length / pow($lower_job_limit, $exponent);
 707         $limit = min($queue_length, ceil($slope * pow($jobs, $exponent)));
 708
 709         logger('Total: '.$jobs.' - Maximum: '.$queue_length.' - jobs per queue: '.$limit, LOGGER_DEBUG);
 710
 711         if (poller_passing_slow($highest_priority)) {
 712                 // Are there waiting processes with a higher priority than the currently highest?
 713                 $result = dba::select('workerqueue', array('id'), array("`executed` <= ? AND `priority` < ? AND NOT `done`", NULL_DATE, $highest_priority),
 714                                 array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true));
 715
 716                 while ($id = dba::fetch($result)) {
 717                         $ids[] = $id["id"];
 718                 }
 719                 dba::close($result);
 720
 721                 $found = (count($ids) > 0);
 722
 723                 if (!$found) {
 724                         // Give slower processes some processing time
 725                         $result = dba::select('workerqueue', array('id'), array("`executed` <= ? AND `priority` > ? AND NOT `done`", NULL_DATE, $highest_priority),
 726                                         array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true));
 727
 728                         while ($id = dba::fetch($result)) {
 729                                 $ids[] = $id["id"];
 730                         }
 731                         dba::close($result);
 732
 733                         $found = (count($ids) > 0);
 734                         $passing_slow = $found;
 735                 }
 736         }
 737
 738         // If there is no result (or we shouldn't pass lower processes) we check without priority limit
 739         if (!$found) {
 740                 $result = dba::select('workerqueue', array('id'), array("`executed` <= ? AND NOT `done`", NULL_DATE),
 741                                 array('limit' => $limit, 'order' => array('priority', 'created'), 'only_query' => true));
 742
 743                 while ($id = dba::fetch($result)) {
 744                         $ids[] = $id["id"];
 745                 }
 746                 dba::close($result);
 747
 748                 $found = (count($ids) > 0);
 749         }
 750
 751         if ($found) {
 752                 $condition = "`id` IN (".substr(str_repeat("?, ", count($ids)), 0, -2).") AND `pid` = 0 AND NOT `done`";
 753                 array_unshift($ids, $condition);
 754                 dba::update('workerqueue', array('executed' => datetime_convert(), 'pid' => $mypid), $ids);
 755         }
 756
 757         return $found;
 758 }
 759
 760 /**
 761  * @brief Returns the next worker process
 762  *
 763  * @param boolean $passing_slow Returns if we had passed low priority processes
 764  * @return string SQL statement
 765  */
 766 function poller_worker_process(&$passing_slow) {
 767         global $poller_db_duration, $poller_lock_duration;
 768
 769         $stamp = (float)microtime(true);
 770
 771         // There can already be jobs for us in the queue.
 772         $r = q("SELECT * FROM `workerqueue` WHERE `pid` = %d AND NOT `done`", intval(getmypid()));
 773         if (dbm::is_result($r)) {
 774                 $poller_db_duration += (microtime(true) - $stamp);
 775                 return $r;
 776         }
 777
 778         $stamp = (float)microtime(true);
 779         if (!Lock::set('poller_worker_process')) {
 780                 return false;
 781         }
 782         $poller_lock_duration = (microtime(true) - $stamp);
 783
 784         $stamp = (float)microtime(true);
 785         $found = find_worker_processes($passing_slow);
 786         $poller_db_duration += (microtime(true) - $stamp);
 787
 788         Lock::remove('poller_worker_process');
 789
 790         if ($found) {
 791                 $r = q("SELECT * FROM `workerqueue` WHERE `pid` = %d AND NOT `done`", intval(getmypid()));
 792         }
 793         return $r;
 794 }
 795
 796 /**
 797  * @brief Removes a workerqueue entry from the current process
 798  */
 799 function poller_unclaim_process() {
 800         $mypid = getmypid();
 801
 802         dba::update('workerqueue', array('executed' => NULL_DATE, 'pid' => 0), array('pid' => $mypid, 'done' => false));
 803 }
 804
 805 /**
 806  * @brief Call the front end worker
 807  */
 808 function call_worker() {
 809         if (!Config::get("system", "frontend_worker")) {
 810                 return;
 811         }
 812
 813         $url = System::baseUrl()."/worker";
 814         fetch_url($url, false, $redirects, 1);
 815 }
 816
 817 /**
 818  * @brief Call the front end worker if there aren't any active
 819  */
 820 function call_worker_if_idle() {
 821         if (!Config::get("system", "frontend_worker")) {
 822                 return;
 823         }
 824
 825         // Do we have "proc_open"? Then we can fork the poller
 826         if (function_exists("proc_open")) {
 827                 // When was the last time that we called the worker?
 828                 // Less than one minute? Then we quit
 829                 if ((time() - Config::get("system", "worker_started")) < 60) {
 830                         return;
 831                 }
 832
 833                 set_config("system", "worker_started", time());
 834
 835                 // Do we have enough running workers? Then we quit here.
 836                 if (poller_too_much_workers()) {
 837                         // Cleaning dead processes
 838                         poller_kill_stale_workers();
 839                         get_app()->remove_inactive_processes();
 840
 841                         return;
 842                 }
 843
 844                 poller_run_cron();
 845
 846                 logger('Call poller', LOGGER_DEBUG);
 847
 848                 $args = array("include/poller.php", "no_cron");
 849                 get_app()->proc_run($args);
 850                 return;
 851         }
 852
 853         // We cannot execute background processes.
 854         // We now run the processes from the frontend.
 855         // This won't work with long running processes.
 856         poller_run_cron();
 857
 858         clear_worker_processes();
 859
 860         $workers = q("SELECT COUNT(*) AS `processes` FROM `process` WHERE `command` = 'worker.php'");
 861
 862         if ($workers[0]["processes"] == 0) {
 863                 call_worker();
 864         }
 865 }
 866
 867 /**
 868  * @brief Removes long running worker processes
 869  */
 870 function clear_worker_processes() {
 871         $timeout = Config::get("system", "frontend_worker_timeout", 10);
 872
 873         /// @todo We should clean up the corresponding workerqueue entries as well
 874         q("DELETE FROM `process` WHERE `created` < '%s' AND `command` = 'worker.php'",
 875                 dbesc(datetime_convert('UTC','UTC',"now - ".$timeout." minutes")));
 876 }
 877
 878 /**
 879  * @brief Runs the cron processes
 880  */
 881 function poller_run_cron() {
 882         logger('Add cron entries', LOGGER_DEBUG);
 883
 884         // Check for spooled items
 885         proc_run(PRIORITY_HIGH, "include/spool_post.php");
 886
 887         // Run the cron job that calls all other jobs
 888         proc_run(PRIORITY_MEDIUM, "include/cron.php");
 889
 890         // Run the cronhooks job separately from cron for being able to use a different timing
 891         proc_run(PRIORITY_MEDIUM, "include/cronhooks.php");
 892
 893         // Cleaning dead processes
 894         poller_kill_stale_workers();
 895 }
 896
 897 if (array_search(__file__,get_included_files())===0) {
 898         poller_run($_SERVER["argv"],$_SERVER["argc"]);
 899
 900         poller_unclaim_process();
 901
 902         get_app()->end_process();
 903
 904         killme();
 905 }