Poller: Now the user limits can be detected automatically as well

diff --git a/include/poller.php b/include/poller.php
index 9976e76db2cd619b85f171eeaa72fd2fb7721a42..d68e8081cac7f39d13eca0674118b3aa0f46a24c 100644 (file)
--- a/include/poller.php
+++ b/include/poller.php
@@ -68,6 +68,10 @@ function poller_run(&$argv, &$argc){
 
        while ($r = q("SELECT * FROM `workerqueue` WHERE `executed` = '0000-00-00 00:00:00' ORDER BY `created` LIMIT 1")) {
 
+               // 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;
@@ -126,15 +130,43 @@ function poller_run(&$argv, &$argc){
  * @return bool Are more than 3/4 of the maximum connections used?
  */
 function poller_max_connections_reached() {
-       $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
-       if (!$r)
-               return false;
 
        // Fetch the max value from the config. This is needed when the system cannot detect the correct value by itself.
-       // In that case we use the processlist to determine the current number of connections
        $max = get_config("system", "max_connections");
 
        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);
+       } else {
+               // Since there are no user specific limitations we will now check for the system values
+               $r = q("SHOW VARIABLES WHERE `variable_name` = 'max_connections'");
+               if (!$r)
+                       return false;
+
                $max = intval($r[0]["Value"]);
                if ($max == 0)
                        return false;
@@ -143,25 +175,19 @@ function poller_max_connections_reached() {
                if (!$r)
                        return false;
 
-               $connected = intval($r[0]["Value"]);
-               if ($connected == 0)
-                       return false;
-       } else {
-               $r = q("SHOW PROCESSLIST");
-               if (!$r)
+               $used = intval($r[0]["Value"]);
+               if ($used == 0)
                        return false;
 
-               $connected = count($r);
+               logger("Connection usage (system values): ".$used."/".$max, LOGGER_DEBUG);
        }
 
-       $level = $connected / $max;
-
-       logger("Connection usage: ".$connected."/".$max, LOGGER_DEBUG);
+       $level = $used / $max;
 
        if ($level < (3/4))
                return false;
 
-       logger("Maximum level (3/4) of connections reached: ".$connected."/".$max);
+       logger("Maximum level (3/4) of connections reached: ".$used."/".$max);
        return true;
 
 }