[pgpool-hackers: 4354] Re: Proposal: mitigating session disconnection issue while failover

[Tatsuo Ishii]

> BTW, I think we need to provide some way to let users find whether
> there is any session that uses the backend node planned to be down as
> the load balance node so that users can know if it's safe to set the
> node to down. I propose to add the info to pcp_process_info and show
> pool_pools. It would be even better if we add new function to
> pgpool_adm extension so that users can SELECT necessary information
> from the output of pcp_process_info. However this should be posted as
> a separate patch.

Patch attached. This patch add new field "load_balance_node" to "SHOW
pool_pools" and pcp_proc_info. The new field is "1" if the entry
represents that the pgpool process is connected by a client and the
session uses the backend id as a load balance node. Users can execute
the command to find out if there's any session that uses the backend
as the load balance node. If so, shutting down the backend may cause
session disconnection.

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