[pgpool-general: 4515] Re: Forked New PCP Worker

[Muhammad Usama]

On Thu, Mar 3, 2016 at 2:07 PM, Tatsuo Ishii <ishii at postgresql.org> wrote:

> Usama,
>
> Can you please add this to our FAQ?  I bet we will have similar
> questions over and over in the future. Registering this to FAQ saves
> both users and developers time a lot.
>

I have updated the FAQ page with this information.

Regards
Muhammad Usama


>
> Best regards,
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese:http://www.sraoss.co.jp
>
> > On Wed, Mar 2, 2016 at 12:52 AM, Burton, Chuck <Chuck.Burton at arris.com>
> > wrote:
> >
> >> We are running pgpool in our lab in a virtualized, dockerized
> environment
> >> with pgpool managing two streaming replicated Postgres nodes.  I am
> running
> >> pgpool 3.5.0.1.
> >>
> >>
> >>
> >> I am using pgbench to connect through pgpool:
> >>
> >>
> >>
> >> /usr/pgsql-9.3/bin/pgbench -c 300 -r -j 5 -t 3334 -h pgpool -p 9999
> dbname
> >>
> >>
> >>
> >> What is happening is I’m getting frequent disconnects of the pcp worker:
> >>
> >>
> >>
> >> 2016-03-01 19:36:48: pid 5369: LOG:  forked new pcp worker, pid=7377
> >> socket=7
> >>
> >> 2016-03-01 19:36:48: pid 5369: LOG:  PCP process with pid: 7377 exit
> with
> >> SUCCESS.
> >>
> >> 2016-03-01 19:36:48: pid 5369: LOG:  PCP process with pid: 7377 exits
> with
> >> status 0
> >>
> >> 2016-03-01 19:36:48: pid 244: LOG:  reload config files.
> >>
> >> 2016-03-01 19:36:48: pid 5370: LOG:  reloading config file
> >>
> >> 2016-03-01 19:37:00: pid 5369: LOG:  forked new pcp worker, pid=7433
> >> socket=7
> >>
> >> 2016-03-01 19:37:00: pid 5369: LOG:  PCP process with pid: 7433 exit
> with
> >> SUCCESS.
> >>
> >> 2016-03-01 19:37:00: pid 5369: LOG:  PCP process with pid: 7433 exits
> with
> >> status 0
> >>
> >> 2016-03-01 19:37:00: pid 244: LOG:  reload config files.
> >>
> >> 2016-03-01 19:37:03: pid 5370: LOG:  reloading config file
> >>
> >
> > This is the normal life cycle of PCP command in pgpool-II 3.5. Previously
> > pgpool-II could only handle single PCP command at a time and all PCP
> > commands were handled by a single PCP child process which lives
> throughout
> > the lifespan of pgpool-II main process.
> > This is now changed in the latest version 3.5. Now for every PCP command
> > issued to pgpool a new PCP child process is forked and that process exits
> > after execution of that PCP command is complete. So the LOG contains the
> > messages about the creation and exit of a PCP worker process, which is
> > perfectly normal.
> >
> >
> >>
> >> Also, occasionally:
> >>
> >>
> >>
> >> 2016-03-01 19:36:18: pid 4497: FATAL:  Backend throw an error message
> >>
> >> 2016-03-01 19:36:18: pid 4497: DETAIL:  Exiting current session because
> of
> >> an error from backend
> >>
> >> 2016-03-01 19:36:18: pid 4497: HINT:  BACKEND Error: "function
> >> pgpool_regclass(unknown) does not exist"
> >>
> >
> > This error message suggests that pgpool_regclass extension is not
> installed
> > on the PostgreSQL backend.
> >
> http://www.pgpool.net/mediawiki/index.php/FAQ#Why_do_I_need_to_install_pgpool_regclass.3F
> >
> > Regards
> > Muhammad Usama
> >
> >
> >>
> >> This happened six times during the five-minute pgbench test.
> >>
> >>
> >>
> >> I am running with:
> >>
> >>
> >>
> >> num_init_children = 1000
> >>
> >>                                    # Number of pools
> >>
> >>                                    # (change requires restart)
> >>
> >> max_pool = 1
> >>
> >>                                    # Number of connections per pool
> >>
> >>                                    # (change requires restart)
> >>
> >> listen_backlog_multiplier = 3
> >>
> >> serialize_accept = on
> >>
> >> child_life_time = 0
> >>
> >>
> >>
> >> Is this a problem with the pcp worker getting overwhelmed?
> >>
> >>
> >>
> >> Looking at the new metrics on show pool_nodes I see that reads are being
> >> distributed.
> >>
> >> _______________________________________________
> >> pgpool-general mailing list
> >> pgpool-general at pgpool.net
> >> http://www.pgpool.net/mailman/listinfo/pgpool-general
> >>
> >>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.sraoss.jp/pipermail/pgpool-general/attachments/20160303/be7596f1/attachment.html>