Hi Jay,
I totally agree with you that having a pair hot standbys will be good. What do you mean by "using WAL shipping in addition to WAL receivers"?According to the documentation, if I configure replication slot, "the master does not remove WAL segments until they have been received by all standbys". In sync replication, if the standby is down, the transaction will not be able to commit. However, if we have a pair, as long as 1 of the hot standby is up, the transaction will still go through.
Hi Jan,
Technically, 2 instance of pg-pool will suffice. However, if we have to bring 1 instance down for maintenance, there's no standby if the master crashes.
Anyway, I do realise a tiny flaw in my design, pg-pool is not a active/active design. It means there's a wasted resource. At least my pair of hot standbys could serve read queries..