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Re: pgpool fundamental questions

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> 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

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TIP 8: explain analyze is your friend

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