[pgpool-general: 5105] Re: pgpool incorrectly thinks backend cluster is down

[Tatsuo Ishii]

> I have pgpool configured against two redshift backend clusters to do
> parallel writes. Seemingly at random, pgpool determines that one or both
> the clusters are down and stops accepting connections even when they are
> not down. I have health check configured every 30 seconds but that does not
> help as it checks heath and still determines they are down in pgpool_status
> file. How is health status determined and written to the file
> /var/log/pgpool/pgpool_status and why does pgpool think the clusters are
> down when they are not?

Whenever Pgpool-II thinks a backend is being down, there should be a
log entry in the Pgpool-II log file. Please check.

> I also tested read query routing and noticed they were being routed
> randomly to the backend clusters. Is there a specific algorithm that pgpool
> uses for read query routing?

Yes, it randomly routes to backends. You can control the possibility
of the routing.

> 
> 
> 
> 
> My config parameters are below
> 
> 
> 
> backend_hostname0 = 'cluster1'
> 
> backend_port0 = 5439
> 
> backend_weight0 = 1
> 
> backend_data_directory0 = '/data1'
> 
> backend_flag0 = 'ALLOW_TO_FAILOVER'
> 
> 
> 
> backend_hostname1 = 'cluster2'
> 
> backend_port1 = 5439
> 
> backend_weight1 = 1
> 
> backend_data_directory1 = '/data1'
> 
> backend_flag1 = 'ALLOW_TO_FAILOVER'
> 
> 
> 
> #-----------------------------------------------------------
> -------------------
> 
> # HEALTH CHECK
> 
> #-----------------------------------------------------------
> -------------------
> 
> 
> 
> health_check_period = 30
> 
>                                    # Health check period
> 
>                                    # Disabled (0) by default
> 
> health_check_timeout = 20
> 
>                                    # Health check timeout
> 
>                                    # 0 means no timeout
> 
> health_check_user = 'username'
> 
>                                    # Health check user
> 
> health_check_password = 'password'
> 
>                                    # Password for health check user
> 
> health_check_max_retries = 10
> 
>                                    # Maximum number of times to retry a
> failed health check before giving up.
> 
> health_check_retry_delay = 1
> 
>                                    # Amount of time to wait (in seconds)
> between retries.