[pgpool-general: 9053] Re: 0 th backend is not valid after upgrading to 4.5.1

[Emond Papegaaij]

Hi all,

I've done some additional investigation and I'm quite confident that this
is the change that is causing the problems:
https://github.com/pgpool/pgpool2/commit/a2a86804cb838b416f317cc083d521a5c691f2ec

The other changes between 4.5.0 and 4.5.1 seem only related to defaults for
settings, which we both set explicitly:
failover_on_backend_shutdown = on
recovery_user = 'keyhub'

We use streaming replication without load balancing:
backend_clustering_mode = 'streaming_replication'
load_balance_mode = off
statement_level_load_balance = off

Switching back to 4.5.0 fixes the issue.

Best regards,
Emond

Op wo 27 mrt 2024 om 09:36 schreef Emond Papegaaij <
emond.papegaaij at gmail.com>:

> Hi,
>
> After upgrading from 4.5.0 to 4.5.1 we see lots of regressions in our
> test-suite when failovers are involved with the following exception in
> WildFly:
> Caused by: org.postgresql.util.PSQLException: ERROR: unable to read
> message kind from backend
>   Detail: 0 th backend is not valid
>
> I'm not sure what is causing this, but I've got the feeling that pgpool
> keeps trying to send queries to a database that not available. I've
> attached logging from pgpool. You can find the first error at 04:10:16
> (or 2024-03-27T03:10:16.735933246Z pgpool timestamp).
>
> Best regards,
> Emond
>
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