[pgpool-general: 6484] Re: pgpool-II does nothing when slave node goes down

[Dmitry Medvedev]

Thank you very much, after specifying the values like
sr_check_* and health_check_* and (OF COURSE!) master_slave_mode = on
everything seems to be OK and pgpool works as expected.

чт, 28 мар. 2019 г. в 02:12, Tatsuo Ishii <ishii at sraoss.co.jp>:

> > Question #1: failover script when stand-by fail.
> >
> > In pgpool.conf there is parameter
> > failover_command = '' # Executes this command at failover
> > But there is no indication what exactly fail means - fail of
> master-server
> > or fail of stand-by server?
>
> Both.
>
> > You wrote "When the standby is stopped, pgpool tries to reconnect x times
> > ... then it does the failover script..." Where in pgpool.conf you defined
> > this script?
>
> The health check parameters.
>
> > Question #2: you wrote "... it detaches the standby".
> > I did exactly the same setting as you wrote, but pgpool stil showing
> > stand-by as "up" meanwhile it is "down".
> > Mayby there is some parameter which exactly tells that stand-by MUST be
> > detached when it fails?
>
> That's not an expected behavior.
> You should share the pgpool log (with log_min_messages = debug5).
>
> > Question #3: you wrote "I  also put the parameter
> failover_on_backend_error
> > = 'off' "
> > Why? If "off" than when master fail occurs - no stand-by promotes. Or I
> > wrong?
>
> Wrong. Setting this parameter to off does not affect the failover
> triggered by health checking.
>
> > вт, 26 мар. 2019 г. в 23:16, Pierre Timmermans <ptim007 at yahoo.com>:
> >
> >> Hi Dimitri
> >>
> >> Did you set-up the health checks ?
> >>
> >> In my pgpool config I have the following parameters related to the
> health
> >> checks
> >>
> >> health_check_period = 10
> >> health_check_timeout = 10
> >> health_check_user = 'hcuser'
> >> health_check_password = 'hcuser'
> >> health_check_database = 'postgres'
> >> health_check_max_retries = 5
> >> health_check_retry_delay = 1
> >>
> >> I  also put the parameter
> >>
> >> failover_on_backend_error = 'off'
> >>
> >> And I created the user hcuser on the postgres database
> >>
> >> When the standby is stopped, pgpool tries to reconnect x times
> (depending
> >> on health_check_max_retries parameter) then it does the failover script
> >> (the script does not have to do something because it is not the primary
> >> failing) and it detaches the standby. When the standby is started again,
> >> pgpool does a failback script (I do nothing in this script) and then it
> >> attaches the standby again
> >>
> >> I believe that if you don't set-up the health-checks pgpool does not
> >> detach the standby when it fails (not sure if it is as-designed or not)
> >>
> >> Pierre
> >>
> >>
> >> On Tuesday, March 26, 2019, 3:58:52 PM GMT+1, Dmitry Medvedev <
> >> dm.dm.medvedev at gmail.com> wrote:
> >>
> >>
> >> Hello to everyone.
> >>
> >> A couple of days I've spent trying to understand how pgpool-II works.
> >> Tell me, please, principle of operation when slave node goes down.
> >> I've read tons of manuals and when master node in my test cluster goes
> >> down (or master's network interface goes down) - pgpool does failover
> >> actions. Everything is OK and works as expected.
> >> But when slave node goes down - pgpool does nothing at all and I receive
> >> such answer
> >>
> >> test=# show pool_nodes;
> >>  node_id |  hostname   | port | status | lb_weight |  role  |
> select_cnt |
> >> load_balance_node | replication_delay | last_status_change
> >>
> >>
> ---------+-------------+------+--------+-----------+--------+------------+-------------------+-------------------+---------------------
> >>  0       | 172.28.30.6 | 5434 | up     | 0.500000  | master | 3
>   |
> >> true              | 0                 | 2019-03-26 17:04:12
> >>  1       | 172.28.30.7 | 5434 | up     | 0.500000  | slave  | 0
>   |
> >> false             | 0                 | 2019-03-26 17:04:12
> >> (2 rows)
> >>
> >>
> >> At the same time slave node is completely down. Not "up"! select * from
> >> pg_stat_replication showing (0 rows)
> >>
> >> Why does pgpool-II does nothing when slave node goes down and how I can
> >> change it?
> >> _______________________________________________
> >> pgpool-general mailing list
> >> pgpool-general at pgpool.net
> >> http://www.pgpool.net/mailman/listinfo/pgpool-general
> >>
>
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