[pgpool-general: 5294] Re: Connections to backends

[Lazaro Garcia]

The reason could by weights = 0 on slaves, try increase this value, then restart pgpool service.

Check load balance is on.

Regards.

-----Mensaje original-----
De: Tema Zelikin [mailto:gunslinger at nightflame.info] 
Enviado el: viernes, 3 de febrero de 2017 03:53 p. m.
Para: Lazaro Garcia; pgpool-general at pgpool.net
Asunto: Re: [pgpool-general: 5290] Connections to backends

I understand the weight functionality, that's why i've set weight of the primary node to 1, and weights of the standby nodes to 0 - so pgpool will send all queries to master node and won't get data from standby nodes.

I also understand the need to connect to all backends for monitoring purposes.

What i DONT understand is why in my case pgpool establishes and maintains a LOT of connections to standby nodes, even when no queries should be sent to those nodes. 


03.02.2017 11:35, Lazaro Garcia пишет:
> The weights property is used for load balancer functionality, with it 
> you can distribute your read queries over your servers for instance 
> 30% to master and 70% to slaves.
>
> Pgpool always tries to connect to servers because failover and 
> swithover functionalities. If the primary server fails, it promotes a new master.
> Because of these it needs to know the current state of the servers
> configured in the cluster.    
>
> As a connection pooler, it maintains open the connections to backends 
> for future use, suppose an app connects to pgpool, send some queries and then
> disconnect, but this connection is saved in the pool for reutilization.     
>
>  Regards.  
>
> -----Mensaje original-----
> De: pgpool-general-bounces at pgpool.net
> [mailto:pgpool-general-bounces at pgpool.net] En nombre de Tema Zelikin 
> Enviado el: viernes, 3 de febrero de 2017 09:50 a. m.
> Para: pgpool-general at pgpool.net
> Asunto: [pgpool-general: 5290] Connections to backends
>
> Hello.
>
> I have a following configuration:
>
> 3 backends with replication in master-slave mode.
> 2 pgpools with delegate_IP and watchdog, with weights of backends as
> following:
> master = 1
> both slaves = 0
>
> My understanding is that pgpool shouldnt make requests to backend 
> nodes with weight of 0.
>
> The question is why does pgpool establishes a connections to those nodes?
>
> Second question, something i couldn't understand from reading a
> documentation: why does number of connections to backends is much more 
> than number of connections to frontend?
>
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