[pgpool-general: 8639] Re: The cluster fails over even when failover_on_backend_error = off

[Ron]

On 3/14/23 03:00, Tatsuo Ishii wrote:
>> PgPool II 4.3.5 and Postgresql 13.10.
>>
>> Three nodes: FISPCCPGS302a, b & c.
>>
>> "a" has the primary database, "b" has the replica, and "c" has the VIP
>> (but no database).
>>
>> One or more times a day, on each node, health_check times out when
>> trying to reach one or two of the others.  (I'm working on figuring
>> out why that happens.)
> Maybe unstable network?  You might want to use "SHOW
> POOL_HEALTH_CHECK_STATS" command.
> https://www.pgpool.net/docs/pgpool-II-4.3.5/en/html/sql-show-pool-health-check-stats.html

health_check_max_retries was set to zero.  I set it to 10 yesterday, so 
we'll see what happens.

>> What else happens is that nodes "b" and "c" will vote to failover from
>> "a" to "b", even though failover_on_backend_error = off.
>>
>> Why does that happen?
>> https://www.pgpool.net/docs/pgpool-II-4.3.5/en/html/runtime-config-failover.html
>> says it should just "report an error and disconnect the session in
>> case of such errors."
>>
>> Is it because "if no client is connected, Pgpool-II will not detect
>> the event even if the parameter is on"?  (This is a pre-production
>> system, so the application servers aren't talking to it.)
>>
>> Attached is a log file extract and PGPOOL SHOW command.
> Turning off failover_on_backend_error prevents pgpool child process

Meaning that "PostgreSQL backend connection" specifically and only refers to 
processes which "do SQL stuff"?

Because aren't /all/ pgpool processes children of the "startup pid"?

> from triggering failover by failures like "An error occurs while
> connecting to PostgreSQL, or network level errors occur while
> communicating with it." (from the manual) This does not affect health
> check process.  i.e. Turning off failover_on_backend_error does not
> prevent pgpool from trigerring failover by health check.
>
> Best reagards,
> --
> Tatsuo Ishii
> SRA OSS LLC
> English:http://www.sraoss.co.jp/index_en/
> Japanese:http://www.sraoss.co.jp

-- 
Born in Arizona, moved to Babylonia.
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