[pgpool-general: 7635] Re: Pgpool replication delay

[valsaraj pv]

Hi,

Set delay_threshold = 30 and load tested. The error is not seen.

The following appearing in log sometimes:
2021-07-08 04:05:13: pid 4285: LOG:  selecting backend connection
2021-07-08 04:05:13: pid 4285: DETAIL:  failover or failback event
detected, discarding existing connections

Any thoughts on this?

Thanks!

On Sat, Jul 3, 2021 at 6:22 AM Tatsuo Ishii <ishii at sraoss.co.jp> wrote:

> >>> Any recommendations for this kind of scenario?
> >>
> >> synchronous_commit = remote_apply will help at the expense of
> >> performance.
> >
> > Another option is, setting delay_threshold of pgpool.conf to lower
> > value. Default is 10000000 which allows large replication delay. So
> > you might want to set smaller value for it.
> >
> > Note that observation of replication delay is done periodically,
> > defined by sr_check_period. This means that if replication delay grows
> > rapidly, the replication delay observed by pgpool could be outdated
> > and pgpool may send SELECT to delayed standby, and you might see the
> > error.
> >
> > In summary delay_threshold is not perfect but can be useful if you
> > want to keep on using asynchronous replication.
>
> Actually Pgpool-II has many other options that might help you. Please
> checkout the manual:
>
> https://www.pgpool.net/docs/latest/en/html/runtime-config-load-balancing.html#RUNTIME-CONFIG-LOAD-BALANCING-SETTINGS
>
> Best regards,
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese:http://www.sraoss.co.jp
>


-- 
Life is like this: "Just when we get all the answers of life.... God
changes the question paper....

Valsaraj Viswanathan
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.pgpool.net/pipermail/pgpool-general/attachments/20210708/5ea78321/attachment.htm>