[pgpool-general: 8667] Re: One node always primary

[Tatsuo Ishii]

>> Hi all,
>> 
>> I would like to know if there is a mechanism to ensure one node is always
>> primary.
>> I have seen the ALWAYS_PRIMARY flag in the config file but I couldn't make
>> it work.
>> I tried to put in the backend_flag the value
>> "ALLOW_TO_FAILOVER|ALWAYS_PRIMARY" with no success.
>> 
>> I have two nodes with streaming replication (server1 and server2). Server1
>> is primary but sometimes I have to power off it and the server2 will be the
>> new master because of the failover. What I need is to make the server1 the
>> new master when it is powered on again.
> 
> I assume you are using Pgpool-II 4.3.0 or higher.
> 
> 1. Power off server1. This will trigger failover and server2 will
>    become new primary.
> 
> 2. Power on server1 but do not start pgpool and PostgreSQL.
> 
> 3. Run pcp_recovery_node on server2 with target node server1 so that
>    server1 becomes standby.
>    e.g. pcp_recovery_node -p xxxx 0
>    (assuming server1 is node 0)
> 
> 4. Run pcp_promote_node on server2 with -s option and target node
>    to server1 so that server1 becomes new primary.
>    e.g. pcp_promote_node -p xxxx -s 0
>    (assuming server1 is node 0)

One thing I forgot to say: You should not use ALWAYS_PRIMARY flag in
order to work the procedure above.

Best reagards,
--
Tatsuo Ishii
SRA OSS LLC
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp