Added shortcut calling convention to getConnection(). Modified load balancing to...

diff --git a/includes/LoadBalancer.php b/includes/LoadBalancer.php
index eb1aa59..87769a5 100644 (file)
--- a/includes/LoadBalancer.php
+++ b/includes/LoadBalancer.php
@@ -95,17 +95,13 @@ class LoadBalancer {
                        return false;
                }
 
-               $sum = 0;
-               foreach ( $weights as $w ) {
-                       $sum += $w;
-               }
-
+               $sum = array_sum( $weights );
                if ( $sum == 0 ) {
                        # No loads on any of them
-                       # Just pick one at random
-                       foreach ( $weights as $i => $w ) {
-                               $weights[$i] = 1;
-                       }
+                       # In previous versions, this triggered an unweighted random selection,
+                       # but this feature has been removed as of April 2006 to allow for strict 
+                       # separation of query groups. 
+                       return false;
                }
                $max = mt_getrandmax();
                $rand = mt_rand(0, $max) / $max * $sum;
@@ -129,7 +125,6 @@ class LoadBalancer {
                        }
                }
 
-
                # Find out if all the slaves with non-zero load are lagged
                $sum = 0;
                foreach ( $loads as $load ) {
@@ -140,7 +135,7 @@ class LoadBalancer {
                        # Do NOT use the master
                        # Instead, this function will return false, triggering read-only mode,
                        # and a lagged slave will be used instead.
-                       unset ( $loads[0] );
+                       return false;
                }
 
                if ( count( $loads ) == 0 ) {
@@ -203,7 +198,9 @@ class LoadBalancer {
                                                        if ( isset( $this->mServers[$i]['max threads'] ) &&
                                                          $status['Threads_running'] > $this->mServers[$i]['max threads'] )
                                                        {
-                                                               # Slave is lagged, wait for a while
+                                                               # Too much load, back off and wait for a while.
+                                                               # The sleep time is scaled by the number of threads connected,
+                                                               # to produce a roughly constant global poll rate.
                                                                $sleepTime = AVG_STATUS_POLL * $status['Threads_connected'];
 
                                                                # If we reach the timeout and exit the loop, don't use it
@@ -340,13 +337,20 @@ class LoadBalancer {
                $fname = 'LoadBalancer::getConnection';
                wfProfileIn( $fname );
 
+
                # Query groups
-               $groupIndex = false;
-               foreach ( $groups as $group ) {
-                       $groupIndex = $this->getGroupIndex( $group );
+               if ( !is_array( $groups ) ) {
+                       $groupIndex = $this->getGroupIndex( $groups, $i );
                        if ( $groupIndex !== false ) {
                                $i = $groupIndex;
-                               break;
+                       }
+               } else {
+                       foreach ( $groups as $group ) {
+                               $groupIndex = $this->getGroupIndex( $group, $i );
+                               if ( $groupIndex !== false ) {
+                                       $i = $groupIndex;
+                                       break;
+                               }
                        }
                }