Meaningful error message when all servers are busy

diff --git a/includes/LoadBalancer.php b/includes/LoadBalancer.php
index 326a83f..89860d7 100644 (file)
--- a/includes/LoadBalancer.php
+++ b/includes/LoadBalancer.php
@@ -36,7 +36,7 @@ class LoadBalancer {
        /* private */ var $mFailFunction, $mErrorConnection;
        /* private */ var $mForce, $mReadIndex, $mLastIndex;
        /* private */ var $mWaitForFile, $mWaitForPos, $mWaitTimeout;
-       /* private */ var $mLaggedSlaveMode;
+       /* private */ var $mLaggedSlaveMode, $mLastError = 'Unknown error';
 
        function LoadBalancer()
        {
@@ -225,6 +225,10 @@ class LoadBalancer {
                                        }
                                } while ( count( $loads ) && !$done && $totalElapsed / 1e6 < $wgDBClusterTimeout );
 
+                               if ( $totalElapsed / 1e6 >= $wgDBClusterTimeout ) {
+                                       $this->mLastError = 'All servers busy';
+                               }
+                               
                                if ( $i !== false && $this->isOpen( $i ) ) {
                                        # Wait for the session master pos for a short time
                                        if ( $this->mWaitForFile ) {
@@ -446,14 +450,23 @@ class LoadBalancer {
                if ( !$reporting ) {
                        $reporting = true;
                        if ( !is_object( $conn ) ) {
+                               // No last connection, probably due to all servers being too busy
                                $conn = new Database;
-                       }
-                       if ( $this->mFailFunction ) {
-                               $conn->failFunction( $this->mFailFunction );
+                               if ( $this->mFailFunction ) {
+                                       $conn->failFunction( $this->mFailFunction );
+                                       $conn->reportConnectionError();
+                               } else {
+                                       // If all servers were busy, mLastError will contain something sensible
+                                       wfEmergencyAbort( $conn, $this->mLastError );
+                               }
                        } else {
-                               $conn->failFunction( false );
+                               if ( $this->mFailFunction ) {
+                                       $conn->failFunction( $this->mFailFunction );
+                               } else {
+                                       $conn->failFunction( false );
+                               }
+                               $conn->reportConnectionError();
                        }
-                       $conn->reportConnectionError();
                        $reporting = false;
                }
                wfProfileOut( $fname );