[pgpool-general: 7635] Re: Pgpool replication delay
valsarajpv at gmail.com
Thu Jul 8 17:18:28 JST 2021
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?
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 rapidly, the replication delay observed by pgpool could be outdated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:
> Best regards,
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
Life is like this: "Just when we get all the answers of life.... God
changes the question paper....
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