從哪個文件修改資料庫路徑？

謝謝回復。
我修改了settings.php中的以下代碼：
$db_url = 'pgsql://username:password@localhost/databasename';
打開網頁後首頁能出現，但下方出現：
Warning: openlog() has been disabled for security reasons in /data/apache/users/.../modules/syslog/syslog.module on line 76
Warning: syslog() has been disabled for security reasons in /data/apache/users/.../modules/syslog/syslog.module on line 79
Warning: MySQL server has gone away query: INSERT INTO watchdog (uid, type, message, variables, severity, link, location, referer, hostname, timestamp) VALUES (…) in /data/apache/users/.../includes/database.mysql.inc on line 128
登錄後進入自己虛擬服務器上的localhost頁面。不知應怎樣解決？

謝謝回覆。設定的是mysql：
* Database URL format:
* $db_url = 'mysql://