[pgpool-general: 6409] Re: health_check_max_retries is not honored

[Alexander Dorogensky]

Pgpool.conf from one of the app nodes is attached

Thanks

On Mon, Feb 11, 2019 at 6:59 PM Bo Peng <pengbo at sraoss.co.jp> wrote:

> Hi,
>
> On Mon, 11 Feb 2019 15:32:55 -0600
> Alexander Dorogensky <amazinglifetime at gmail.com> wrote:
>
> > I'm running 4 app (pgpool) nodes (3.6.10) and 2 db (postgres) nodes
> (9.6.9)
> > primary/standby configuration with streaming replication. All 6 nodes are
> > separate machines.
> >
> > A client has had too many failovers caused by the flaky network and in an
> > effort to remedy the issue I set the following parameters
> >
> > health_check_max_retries = 7
> > health_check_retry_delay = 15
> >
> > Now, I have the client's environment and a lab environment to reproduce
> the
> > issue. Pgpool configuration and the version are identical.
> >
> > To simulate a flaky network, I use iptables to deny postgres connections
> to
> > one of the db nodes and see that pgpool on all app nodes is trying to
> > reconnect according to the configured number of retries and retry delay,
> >
> > > i.e.
> > > 2019-02-11 14:22:51: pid 7825: LOG:  failed to connect to PostgreSQL
> > > server on "10.0.10.133:5433", getsockopt() detected error "No route to
> > > host"
> > > ...
> > > 2019-02-11 14:23:23: pid 6458: LOG:  health checking retry count 1
> > > ...
> > > 2019-02-11 14:23:38: pid 6458: LOG:  health checking retry count 2
> > > ...
> > > 2019-02-11 14:42:45: pid 6458: LOG:  health checking retry count 3
> > > ...
> > > 2019-02-11 14:43:00: pid 6458: LOG:  health checking retry count 4
> > > ...
> > > 2019-02-11 14:43:15: pid 6458: LOG:  health checking retry count 5
> > > ...
> > > 2019-02-11 14:43:30: pid 6458: LOG:  health checking retry count 6
> > > ...
> > > 2019-02-11 14:43:30: pid 6460: LOG:  failover request from local
> pgpool-II
> > > node received on IPC interface is forwarded to master watchdog node "
> > > 172.20.20.173:5432"
> > > 2019-02-11 14:43:30: pid 4565: LOG:  watchdog received the failover
> > > command from remote pgpool-II node "172.20.20.172:5432"
> > > ...
> > > 2019-02-11 14:43:30: pid 4563: LOG:  execute command:
> > > /etc/pgpool-II/failover.sh 0 10.0.10.133 5433 /opt/redsky/db/data 1 0
> > > 10.0.10.134 1 5433 /opt/redsky/db/data
> > >
> > > However, in the client's environment failover gets initiated before the
> > configured number of retries, i.e.
> >
> > 2019-02-09 05:17:47: pid 19402: LOG:  watchdog received the failover
> > > command from local pgpool-II on IPC interface
> > > 2019-02-09 05:17:47: pid 19402: LOG:  watchdog is processing the
> failover
> > > command [DEGENERATE_BACKEND_REQUEST] received from local pgpool-II on
> IPC
> > > interface
> > > 2019-02-09 05:17:47: pid 19402: LOG:  forwarding the failover request
> > > [DEGENERATE_BACKEND_REQUEST] to all alive nodes
> > > 2019-02-09 05:17:47: pid 19402: DETAIL:  watchdog cluster currently
> has 3
> > > connected remote nodes
> > > 2019-02-09 05:17:47: pid 19276: ERROR:  unable to read data from DB
> node 1
> > > 2019-02-09 05:17:47: pid 19276: DETAIL:  socket read failed with an
> error
> > > "Success"
> > > 2019-02-09 05:17:47: pid 19400: LOG:  Pgpool-II parent process has
> > > received failover request
> > > 2019-02-09 05:17:47: pid 19402: LOG:  new IPC connection received
> > > 2019-02-09 05:17:47: pid 19402: LOG:  received the failover command
> lock
> > > request from local pgpool-II on IPC interface
> > > 2019-02-09 05:17:47: pid 19402: LOG:  local pgpool-II node "
> > > 10.15.35.35:5432" is requesting to become a lock holder for failover
> ID:
> > > 19880
> > > 2019-02-09 05:17:47: pid 19402: LOG:  local pgpool-II node "
> > > 10.15.35.35:5432" is the lock holder
> > > 2019-02-09 05:17:47: pid 19400: LOG:  starting degeneration. shutdown
> host
> > > 10.38.135.137(5433)
> > > 2019-02-09 05:17:47: pid 19400: LOG:  Restart all children
> > > 2019-02-09 05:17:47: pid 19400: LOG:  execute command:
> > > /etc/pgpool-II/failover.sh 1 10.38.135.137 5433 /opt/redsky/db/data 0 0
> > > 10.15.35.39 1 5433 /opt/redsky/db/data
> > >
> > >
> > I ran the following command on all app nodes
> >
> > psql -c 'pgpool show health_check_max_retries'
> > health_check_max_retries
> > --------------------------
> > 16
> > (1 row)
> >
> > and the number is different from what I have in the configuration file..
> > It's more than 1 though and I expect it to be honored.
>
> I could not reproduce this issue by using pgpool_setup.
> Could you share the whole pgpool.conf?
>
> > Can you guys help me out? I'm out of ideas..
> >
> > pgpool-II-pg96-3.6.10-1pgdg.rhel6.x86_64
>
>
> --
> Bo Peng <pengbo at sraoss.co.jp>
> SRA OSS, Inc. Japan
>
>
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