pgpool-II introduce the problem of a single point of failure. pgpool-II failure can cause complete database service shutdown and make the whole database system unavailable. To overcome this problem, pgpool-II provides the watchdog feature for high availability. To avoid a single point of failure, install two or more pgpool-IIs and enable the watchdog feature. Full details of this feature can be found at http://www.pgpool.net/pgpool-web/contrib_docs/watchdog/en.html.