Oracle cannot release savepoints

lib/Doctrine/DBAL/Connection.php

@@ -884,7 +884,7 @@ class Connection implements DriverConnection
             ConnectionException::savepointsNotSupported();
         }
 
-        return $this->_conn->exec($this->_platform->createSavePoint($savepoint));
+        $this->_conn->exec($this->_platform->createSavePoint($savepoint));
     }
 
     /**
@@ -900,7 +900,10 @@ class Connection implements DriverConnection
             ConnectionException::savepointsNotSupported();
         }
 
-        return $this->_conn->exec($this->_platform->releaseSavePoint($savepoint));
+        $sql = $this->_platform->releaseSavePoint($savepoint);
+        if ($sql) {
+            $this->_conn->exec($sql);
+        }
     }
 
     /**
@@ -916,7 +919,7 @@ class Connection implements DriverConnection
             ConnectionException::savepointsNotSupported();
         }
 
-        return $this->_conn->exec($this->_platform->rollbackSavePoint($savepoint));
+        $this->_conn->exec($this->_platform->rollbackSavePoint($savepoint));
     }
 
     /**

lib/Doctrine/DBAL/Platforms/OraclePlatform.php

@@ -700,4 +700,15 @@ LEFT JOIN all_cons_columns r_cols
             'urowid'            => 'string'
         );
     }
+
+    /**
+     * Generate SQL to release a savepoint
+     *
+     * @param string $savepoint
+     * @return string
+     */
+    public function releaseSavePoint($savepoint)
+    {
+        return '';
+    }
 }