[pgpool-general: 6419] Re: health_check_max_retries is not honored

[Bo Peng]

Hi,

I confirmed your pgpool.conf, you set 

  health_check_max_retries = 16

So I think the following result is correct. 

> >> > psql -c 'pgpool show health_check_max_retries'
> >> > health_check_max_retries
> >> > --------------------------
> >> > 16
> >> > (1 row)

On Fri, 15 Feb 2019 07:12:56 -0500
Alexander Dorogensky <amazinglifetime at gmail.com> wrote:

> Hi,
> 
> Do you have any ideas what’s going on?
> 
> On Mon, Feb 11, 2019 at 8:30 PM Alexander Dorogensky <
> amazinglifetime at gmail.com> wrote:
> 
> > 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
> >>
> >>


-- 
Bo Peng <pengbo at sraoss.co.jp>
SRA OSS, Inc. Japan