Chapter 2. Watchdog

Table of Contents
2.1. Introduction
2.1.1. Coordinating multiple Pgpool-II nodes
2.1.2. Life checking of other Pgpool-II nodes
2.1.3. Consistency of configuration parameters on all Pgpool-II nodes
2.1.4. Changing active/standby state when certain fault is detected
2.1.5. Automatic virtual IP switching
2.1.6. Automatic registration of a server as a standby in recovery
2.1.7. Starting/stopping watchdog
2.2. Integrating external lifecheck with watchdog
2.2.1. Watchdog IPC command packet format
2.2.2. Watchdog IPC result packet format
2.2.3. Watchdog IPC command packet types
2.2.4. External lifecheck IPC packets and data
2.3. Restrictions on watchdog
2.3.1. Watchdog restriction with query mode lifecheck
2.3.2. Connecting to Pgpool-II whose watchdog status is down
2.3.3. Pgpool-II whose watchdog status is down requires restart
2.3.4. Watchdog promotion to active takes few seconds
2.4. Architecure of the watchdog
2.4.1. Watchdog Core
2.4.2. Watchdog Lifecheck