public function initIndexing(\PDO $db)
    {

        // delete everything before reset indexing
        $dir = opendir($this->SqliteDir);
        while ($file = readdir($dir)) {
            if ($file != '.' && $file != '..' && $file != 'indexing' && $file != 'dbfastcache') {
                unlink($this->SqliteDir . '/' . $file);
            }
        }

        $db->exec('DROP TABLE if exists "balancing"');
        $db->exec('CREATE TABLE "balancing" ("keyword" VARCHAR PRIMARY KEY NOT NULL UNIQUE, "db" INTEGER)');
        $db->exec('CREATE INDEX "db" ON "balancing" ("db")');
        $db->exec('CREATE UNIQUE INDEX "lookup" ON "balancing" ("keyword")');

    }