Re: pgpool fundamental questions

> Pgpool is a real cool project, I really hope it keeps evolving. I have a couple basic/fundamental questions that I hoping to get some clarification on.
>
> Question 1: If pgpool is used in conjuntion with slony or a another replication it can be used only for its loadbalancing and failover. I am correct like this? What else needs to be done to set in failover?
>
> set the backends....
>
> backend_host_name =master
> secondary_backend_host_name=slave
>
> set it to lb on and replication off...
>
> load_balance_mode=true
> replication_mode=false
>
> set the health checks for failover.
>
> health_check_timeout=20
> health_check_period=20
> health_check_user=user

You need to set master_slave_mode to true.

> Question 2: In the case that the master goes down pgpool would failover to the slave/secondary. What would be the logical steps to bring it back to normal. Can this be down with no downtime with both?

> 1) Turn off health check or weight the weight_master =0 so when you bring the master back load does not go to it when you bring the db backup. or does pgpool leave it down automatically until you restart pgpool?

Yes.

> 2) Shutdown replication on the master. Bring back the master backup.
>
> 3) rsynch the data from the slave to the master???
>
> 4) turn replication?

It seems these steps OK. But you are going to use Slony-I with pgpool,
no? Then you might want to sync DBs using Slony-I?

> Question 3: Is there anyway to make pgpool loadbalance certain select queries to the slave such as queries to a particular table? Is that a future feature planned?

Since pgpool does not parse queries, probably it would not happen in
the future. Ideas are welcome how to know a query is accessing
particular table without parsing it.
--
Tatsuo Ishii