Merge "Log to DBPerformance log when many LB connections are acquired"

diff --git a/includes/db/LoadBalancer.php b/includes/db/LoadBalancer.php
index 8618ae6..4c9fd32 100644 (file)
--- a/includes/db/LoadBalancer.php
+++ b/includes/db/LoadBalancer.php
@@ -58,9 +58,14 @@ class LoadBalancer {
        private $mLaggedSlaveMode;
        /** @var string The last DB selection or connection error */
        private $mLastError = 'Unknown error';
+       /** @var integer Total connections opened */
+       private $connsOpened = 0;
        /** @var ProcessCacheLRU */
        private $mProcCache;
 
+       /** @var integer Warn when this many connection are held */
+       const CONN_HELD_WARN_THRESHOLD = 10;
+
        /**
         * @param array $params Array with keys:
         *   servers           Required. Array of server info structures.
@@ -734,6 +739,14 @@ class LoadBalancer {
                        $server['dbname'] = $dbNameOverride;
                }
 
+               // Log when many connection are made on requests
+               if ( ++$this->connsOpened >= self::CONN_HELD_WARN_THRESHOLD ) {
+                       $masterAddr = $this->getServerName( 0 );
+                       wfDebugLog( 'DBPerformance', __METHOD__ . ": " .
+                               "{$this->connsOpened}+ connections made (master=$masterAddr)\n" .
+                               wfBacktrace( true ) );
+               }
+
                # Create object
                try {
                        $db = DatabaseBase::factory( $server['type'], $server );
@@ -905,6 +918,7 @@ class LoadBalancer {
                        'foreignFree' => array(),
                        'foreignUsed' => array(),
                );
+               $this->connsOpened = 0;
        }
 
        /**
@@ -921,6 +935,7 @@ class LoadBalancer {
                                        if ( $conn === $candidateConn ) {
                                                $conn->close();
                                                unset( $this->mConns[$i1][$i2][$i3] );
+                                               --$this->connsOpened;
                                                $done = true;
                                                break;
                                        }