Well 3.3 focuses on maturing 3.2: especially "watchdog" part. The watchdog was new in 3.2, allows to prevent a single point of failure of pgpool itself. I know we already have pgpool-HA, but the watchdog does more. It can make more than two pgpool's working together, for example, on line recovery.
In 3.3 the watchdog is much more enhanced:
- New life check method (“heart beat”) added
- Redundant heart beat device support
- Secure protocol for heart beat and other messages
- Interlocking of fail over/fail back/follow maser script
- Monitor and auto restart watchdog process if it goes down