[pgpool-general: 8205] Re: rejecting connections when num_init_children reached

[Travis Kirstine]

Thanks Bo
So the following would be expected where I have 4 backend databases

config
num_init_children = 25
max_pool = 4

Database_A : active connects 25
Database_B: connections blocked
Database_C: connections blocked
Database_D: connections blocked

My expectation based on the docs would be that I have 25 forked processes
per max_pool (4x25), 100 connections available in total.

Regards






On Thu, 2 Jun 2022 at 00:21, Bo Peng <pengbo at sraoss.co.jp> wrote:

> Hello,
>
> > Hi all,
> >
> > I'm using pgpool v3.4.3 and have the following setup
> >
> > num_init_children = 25
> > max_pool = 4
> >
> > >From my understanding this would allow for 4 unique db user combinations
> > each with 25 preforked processes / connections.  I have noticed that when
> > the num_init_childern process count is reached for one unique combination
> > (db_a) it will block / slow down connections to db_b which have not
> reached
> > that limit.
> >
> > We are using pgbouncer in front of pgpool which is creating persistent
> > connections which could be part of the problem.
> >
> > Could I be right
>
> It is the expected behavior.
>
> Pgpool-II accepts requests up to "num_init_children".
> If num_init_children is reached, the subsequent request will be blocked
> until any other connections is closed
>
>
> https://www.pgpool.net/docs/latest/en/html/runtime-config-connection.html#GUC-NUM-INIT-CHILDREN
> --
> Bo Peng <pengbo at sraoss.co.jp>
> SRA OSS, Inc. Japan
> http://www.sraoss.co.jp/
>
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