You can use the HotStandby.AutoPrimaryAlone parameter to control whether the primary server automatically switches to PRIMARY ALONE state or stays in PRIMARY UNCERTAIN state after it has lost contact with the secondary server.

If HotStandby.AutoPrimaryAlone is set to yes, when the primary server loses contact with the secondary server, the primary server switches automatically to the PRIMARY ALONE state. The PRIMARY ALONE state means that the primary server continues to accept transactions.

If HotStandby.AutoPrimaryAlone is set to no (default value), when the primary server loses contact with the secondary server, the primary server switches automatically to the PRIMARY UNCERTAIN state.

The PRIMARY UNCERTAIN state prevents the primary server from accepting new transactions or committing the currently active transactions. The primary server does not switch to PRIMARY ALONE state until HAC, the Watchdog, or administrator executes the ADMIN COMMAND 'hotstandby set primary alone' command.