[pgpool-general: 8494] Re: received degenerate backend request for node_id: 0 from pid [$pid]

[Bo Peng]

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:
> 
> 
> [unknown] pid 3166920: LOG:  received degenerate backend request for node_id: 0 from pid [3166920]
> [unknown] pid 3166920: LOG:  signal_user1_to_parent_with_reason(0)
> main pid 1486879: LOG:  Pgpool-II parent process received SIGUSR1
> main pid 1486879: LOG:  Pgpool-II parent process has received failover request
> main pid 1486879: LOG:  starting degeneration. shutdown host <IP redacted>(5995)
> main pid 1486879: LOG:  Restart all children
> main pid 1486879: LOG:  find_primary_node_repeatedly: waiting for finding a primary node
> main pid 1486879: LOG:  failover: set new primary node: 0
> main pid 1486879: LOG:  failover: set new main node: 1
> failover done. shutdown host <IP redacted>(5995)
> 
> 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".

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

-- 
Bo Peng <pengbo at sraoss.co.jp>
SRA OSS LLC
https://www.sraoss.co.jp/