[pgpool-general: 8495] Re: received degenerate backend request for node_id: 0 from pid [$pid]

[Giuseppe Sacco]

Hi

Il giorno mar, 15/11/2022 alle 14.30 +0900, Bo Peng ha scritto:
Hi,

> Hello,
> we are still investigating about a problem in which pgpool sets our
> master as
> down while it seems to be working fine.
> Browsing all the logs about the time of the problem, we found those
> lines:
> 
> [...]
> What does these lines means? What does it means "received degenerate
> backend
> request"?


The message means Pgpool-II will degenerate this backend node and mark it
as DOWN status.
Could you show more logs before "received degenerate backend request for
node_id".

This is another similar log with some more previous lines:

pgpool[3172752]: 2022-11-14 17:52:52.126: child pid 3172752: LOG:  using clear text authentication with frontend
pgpool[3172752]: 2022-11-14 17:52:52.126: child pid 3172752: DETAIL:  backend will still use SCRAM auth
pgpool[3172752]: 2022-11-14 17:52:52.126: child pid 3172752: HINT:  you can disable this behavior by setting allow_clear_text_frontend_auth to off
pgpool[3172752]: 2022-11-14 17:52:52.255: child pid 3172752: ERROR:  backend authentication failed
pgpool[3172752]: 2022-11-14 17:52:52.255: child pid 3172752: DETAIL:  backend response with kind 'E' when expecting 'R'
pgpool[3172752]: 2022-11-14 17:57:52.107: child pid 3172752: LOG:  using clear text authentication with frontend
pgpool[3172752]: 2022-11-14 17:57:52.107: child pid 3172752: DETAIL:  backend will still use SCRAM auth
pgpool[3172752]: 2022-11-14 17:57:52.107: child pid 3172752: HINT:  you can disable this behavior by setting allow_clear_text_frontend_auth to off
pgpool[3172752]: 2022-11-14 17:57:52.237: child pid 3172752: ERROR:  backend authentication failed
pgpool[3172752]: 2022-11-14 17:57:52.237: child pid 3172752: DETAIL:  backend response with kind 'E' when expecting 'R'
pgpool[3166920]: 2022-11-14 18:01:27.927: [unknown] pid 3166920: LOG:  received degenerate backend request for node_id: 0 from pid [3166920]
pgpool[3166920]: 2022-11-14 18:01:27.927: [unknown] pid 3166920: LOG:  signal_user1_to_parent_with_reason(0)

note: we are using allow_clear_text_frontend_auth=on on purpose.

> Are you using native replication mode?
> If your PostgreSQL noeds are in streaming replication mode,
> you need to set "backend_clustering_mode = 'streaming_replication'".

Yes, we are in streaming replication and that parameter is as you suggest.

Thank you,
Giuseppe