unset($db_host, $db_user, $db_pass, $db_data);
};
- if(function_exists('sys_getloadavg')) {
- $maxsysload = intval(get_config('system','maxloadavg'));
- if($maxsysload < 1)
- $maxsysload = 50;
+ if ($a->max_processes_reached())
+ return;
- $load = sys_getloadavg();
- if(intval($load[0]) > $maxsysload) {
- logger('system: load ' . $load[0] . ' too high. poller deferred to next scheduled run.');
- return;
- }
- }
+ if (poller_max_connections_reached())
+ return;
+
+ if (App::maxload_reached())
+ return;
// Checking the number of workers
- if (poller_too_much_workers(1))
+ if (poller_too_much_workers(1)) {
+ poller_kill_stale_workers();
return;
+ }
if(($argc <= 1) OR ($argv[1] != "no_cron")) {
// Run the cron job that calls all other jobs
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($pid["pid"]));
- else {
- // To-Do: Kill long running processes
- // But: Update processes (like the database update) mustn't be killed
- }
-
+ poller_kill_stale_workers();
} else
// Sleep four seconds before checking for running processes again to avoid having too many workers
sleep(4);
while ($r = q("SELECT * FROM `workerqueue` WHERE `executed` = '0000-00-00 00:00:00' ORDER BY `created` LIMIT 1")) {
+ // Constantly check the number of parallel database processes
+ if ($a->max_processes_reached())
+ return;
+
+ // Constantly check the number of available database connections to let the frontend be accessible at any time
+ if (poller_max_connections_reached())
+ return;
+
+ // Count active workers and compare them with a maximum value that depends on the load
+ if (poller_too_much_workers(3))
+ return;
+
q("UPDATE `workerqueue` SET `executed` = '%s', `pid` = %d WHERE `id` = %d AND `executed` = '0000-00-00 00:00:00'",
dbesc(datetime_convert()),
intval(getmypid()),
// Quit the poller once every hour
if (time() > ($starttime + 3600))
return;
+ }
- // Count active workers and compare them with a maximum value that depends on the load
- if (poller_too_much_workers(3))
- return;
+}
+
+/**
+ * @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;
+
+ $used = count($r);
+
+ logger("Connection usage (user values): ".$used."/".$max, LOGGER_DEBUG);
+
+ $level = ($used / $max) * 100;
+
+ if ($level >= $maxlevel) {
+ logger("Maximum level (".$maxlevel."%) of user connections reached: ".$used."/".$max);
+ return true;
+ }
}
+ // 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) {
$active = poller_active_workers();
// Decrease the number of workers at higher load
- if(function_exists('sys_getloadavg')) {
- $load = max(sys_getloadavg());
-
+ $load = current_load();
+ if($load) {
$maxsysload = intval(get_config('system','maxloadavg'));
if($maxsysload < 1)
$maxsysload = 50;
projects / friendica.git / blobdiff