[pgpool-general: 9218] Re: Load balancing of write queries among health-checked nodes

[Tatsuo Ishii]

>> What do you mean by "detached Pgpool instance"? It is possible to
>> detach PostgreSQL instance from pgpool but there's no such an
>> operation to detach pgpool.
> 
> I mean that it is not in the quorum. For example, we have 3 Pgpool
> instances, the client has connectivity with all of them, but Pgpool #3
> doesn't have connectivity with Pgpool #1 and #2. So the quorum
> consists of #1 and #2, and #3 should consider itself as dead and not
> allow to perform any SQL query.

I see. In the case above, pgpool #3 shpuld lose the quorum. You can
check it by using pcp_watchdog_info -v.

$ pcp_watchdog_info -h pgpool#3_host -p pgpool#3_pcp_port -v|grep "Quorum state"

The result should be:
Quorum state             : QUORUM ABSENT

Then the clients should avoid to connect to pgpool#3. Instead, connect
to #1 or #2.  Unfortunately currently there's no way to make this
happen automatically.

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