X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=include%2Fpoller.php;h=d134f30d0fac270001d5cac8d9e98bc1411d81d7;hb=18bd7f5eb7153726d616297981e04816798b5463;hp=e33167c5b14667eba38e01b18a38e5da755ccbe5;hpb=ae21c40f21ab4bb5a482d63ae35beff18efa13be;p=friendica.git

diff --git a/include/poller.php b/include/poller.php
index e33167c5b1..d134f30d0f 100644
--- a/include/poller.php
+++ b/include/poller.php
@@ -26,15 +26,19 @@ function poller_run(&$argv, &$argc){
 		unset($db_host, $db_user, $db_pass, $db_data);
 	};
 
-	$maxsysload = intval(get_config('system','maxloadavg'));
-	if($maxsysload < 1)
-		$maxsysload = 50;
-	if(function_exists('sys_getloadavg')) {
-		$load = sys_getloadavg();
-		if(intval($load[0]) > $maxsysload) {
-			logger('system: load ' . $load[0] . ' too high. poller deferred to next scheduled run.');
-			return;
-		}
+	if ($a->max_processes_reached())
+		return;
+
+	if (poller_max_connections_reached())
+		return;
+
+	if (App::maxload_reached())
+		return;
+
+	// Checking the number of workers
+	if (poller_too_much_workers(1)) {
+		poller_kill_stale_workers();
+		return;
 	}
 
 	if(($argc <= 1) OR ($argv[1] != "no_cron")) {
@@ -45,44 +49,45 @@ function poller_run(&$argv, &$argc){
 		proc_run("php","include/cronhooks.php");
 
 		// Cleaning dead processes
-		$r = q("SELECT DISTINCT(`pid`) FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
-		foreach($r AS $pid)
-			if (!posix_kill($pid["pid"], 0))
-				q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
-					intval($pid["pid"]));
-
+		poller_kill_stale_workers();
 	} else
-		// Sleep two seconds before checking for running processes to avoid having too many workers
+		// Sleep four seconds before checking for running processes again to avoid having too many workers
 		sleep(4);
 
 	// Checking number of workers
-	if (poller_too_much_workers())
+	if (poller_too_much_workers(2))
 		return;
 
 	$starttime = time();
 
 	while ($r = q("SELECT * FROM `workerqueue` WHERE `executed` = '0000-00-00 00:00:00' ORDER BY `created` LIMIT 1")) {
 
-		if(function_exists('sys_getloadavg')) {
-			$load = sys_getloadavg();
-			if(intval($load[0]) > $maxsysload) {
-				logger('system: load ' . $load[0] . ' too high. poller deferred to next scheduled run.');
-				return;
-			}
-		}
+		// Constantly check the number of parallel database processes
+		if ($a->max_processes_reached())
+			return;
 
-		// Quit the poller once every hour
-		if (time() > ($starttime + 3600))
+		// Constantly check the number of available database connections to let the frontend be accessible at any time
+		if (poller_max_connections_reached())
 			return;
 
-		if (poller_too_much_workers())
+		// Count active workers and compare them with a maximum value that depends on the load
+		if (poller_too_much_workers(3))
 			return;
 
-		q("UPDATE `workerqueue` SET `executed` = '%s', `pid` = %d WHERE `id` = %d",
+		q("UPDATE `workerqueue` SET `executed` = '%s', `pid` = %d WHERE `id` = %d AND `executed` = '0000-00-00 00:00:00'",
 			dbesc(datetime_convert()),
 			intval(getmypid()),
 			intval($r[0]["id"]));
 
+		// Assure that there are no tasks executed twice
+		$id = q("SELECT `id` FROM `workerqueue` WHERE `id` = %d AND `pid` = %d",
+			intval($r[0]["id"]),
+			intval(getmypid()));
+		if (!$id) {
+			logger("Queue item ".$r[0]["id"]." was executed multiple times - skip this execution", LOGGER_DEBUG);
+			continue;
+		}
+
 		$argv = json_decode($r[0]["parameter"]);
 
 		$argc = count($argv);
@@ -101,42 +106,162 @@ function poller_run(&$argv, &$argc){
 		$funcname=str_replace(".php", "", basename($argv[0]))."_run";
 
 		if (function_exists($funcname)) {
-			logger("Process ".getmypid().": ".$funcname." ".$r[0]["parameter"]);
+			logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." ".$r[0]["parameter"]);
 			$funcname($argv, $argc);
 
-			logger("Process ".getmypid().": ".$funcname." - done");
+			logger("Process ".getmypid()." - ID ".$r[0]["id"].": ".$funcname." - done");
 
 			q("DELETE FROM `workerqueue` WHERE `id` = %d", intval($r[0]["id"]));
 		} else
 			logger("Function ".$funcname." does not exist");
+
+		// Quit the poller once every hour
+		if (time() > ($starttime + 3600))
+			return;
 	}
 
 }
 
-function poller_too_much_workers() {
+/**
+ * @brief Checks if the number of database connections has reached a critical limit.
+ *
+ * @return bool Are more than 3/4 of the maximum connections used?
+ */
+function poller_max_connections_reached() {
+
+	// Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
+	$max = get_config("system", "max_connections");
+
+	// Fetch the percentage level where the poller will get active
+	$maxlevel = get_config("system", "max_connections_level");
+	if ($maxlevel == 0)
+		$maxlevel = 75;
+
+	if ($max == 0) {
+		// the maximum number of possible user connections can be a system variable
+		$r = q("SHOW VARIABLES WHERE `variable_name` = 'max_user_connections'");
+		if ($r)
+			$max = $r[0]["Value"];
+
+		// Or it can be granted. This overrides the system variable
+		$r = q("SHOW GRANTS");
+		if ($r)
+			foreach ($r AS $grants) {
+				$grant = array_pop($grants);
+				if (stristr($grant, "GRANT USAGE ON"))
+					if (preg_match("/WITH MAX_USER_CONNECTIONS (\d*)/", $grant, $match))
+						$max = $match[1];
+			}
+	}
+
+	// If $max is set we will use the processlist to determine the current number of connections
+	// The processlist only shows entries of the current user
+	if ($max != 0) {
+		$r = q("SHOW PROCESSLIST");
+		if (!$r)
+			return false;
 
-	if(function_exists('sys_getloadavg')) {
-		$load = sys_getloadavg();
+		$used = count($r);
 
-		// To-Do
-		if ($load < 1)
-			$queues = 10;
-		elseif ($load < 5)
-			$queues = 4;
-		elseif ($load < 10)
-			$queues = 2;
-		else
-			$queues = 1;
+		logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
 
-	} else {
-		$queues = intval(get_config("system", "worker_queues"));
+		$level = ($used / $max) * 100;
 
-		if ($queues == 0)
-			$queues = 4;
+		if ($level >= $maxlevel) {
+			logger("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
+			return true;
+		}
 	}
 
-	if (poller_active_workers() >= $queues)
+	// We will now check for the system values.
+	// This limit could be reached although the user limits are fine.
+	$r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
+	if (!$r)
+		return false;
+
+	$max = intval($r[0]["Value"]);
+	if ($max == 0)
+		return false;
+
+	$r = q("SHOW STATUS WHERE `variable_name` = 'Threads_connected'");
+	if (!$r)
+		return false;
+
+	$used = intval($r[0]["Value"]);
+	if ($used == 0)
+		return false;
+
+	logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
+
+	$level = $used / $max * 100;
+
+	if ($level < $maxlevel)
+		return false;
+
+	logger("Maximum level (".$level."%) of system connections reached: ".$used."/".$max);
+	return true;
+}
+
+/**
+ * @brief fix the queue entry if the worker process died
+ *
+ */
+function poller_kill_stale_workers() {
+	$r = q("SELECT `pid`, `executed` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");
+
+	if (!dbm::is_result($r)) {
+		// No processing here needed
 		return;
+	}
+
+	foreach($r AS $pid)
+		if (!posix_kill($pid["pid"], 0))
+			q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
+				intval($pid["pid"]));
+		else {
+			// Kill long running processes
+			$duration = (time() - strtotime($pid["executed"])) / 60;
+			if ($duration > 180) {
+				logger("Worker process ".$pid["pid"]." took more than 3 hours. It will be killed now.");
+				posix_kill($pid["pid"], SIGTERM);
+
+				// Question: If a process is stale: Should we remove it or should we reschedule it?
+				// By now we rescheduling it. It's maybe not the wisest decision?
+				q("UPDATE `workerqueue` SET `executed` = '0000-00-00 00:00:00', `pid` = 0 WHERE `pid` = %d",
+					intval($pid["pid"]));
+			} else
+				logger("Worker process ".$pid["pid"]." now runs for ".round($duration)." minutes. That's okay.", LOGGER_DEBUG);
+		}
+}
+
+function poller_too_much_workers($stage) {
+
+	$queues = get_config("system", "worker_queues");
+
+	if ($queues == 0)
+		$queues = 4;
+
+	$active = poller_active_workers();
+
+	// Decrease the number of workers at higher load
+	$load = current_load();
+	if($load) {
+		$maxsysload = intval(get_config('system','maxloadavg'));
+		if($maxsysload < 1)
+			$maxsysload = 50;
+
+		$maxworkers = $queues;
+
+		// Some magical mathemathics to reduce the workers
+		$exponent = 3;
+		$slope = $maxworkers / pow($maxsysload, $exponent);
+		$queues = ceil($slope * pow(max(0, $maxsysload - $load), $exponent));
+
+		logger("Current load stage ".$stage.": ".$load." - maximum: ".$maxsysload." - current queues: ".$active." - maximum: ".$queues, LOGGER_DEBUG);
+
+	}
+
+	return($active >= $queues);
 }
 
 function poller_active_workers() {