[Pgpool-general] pgpool problems

[Tatsuo Ishii]

> Hi Tatsuo,
> 
> greetings to Japan!

greetings to Denmark!

> > pg_pconnect will eat up all pgpool child processes(number of them is
> > 64, in your case). If you want to keep using pg_pconnect, you need to
> > increase num_init_chidren until it exceeds number of possible Apache
> > child processes (probably this is defined by MaxClients directive in
> > httpd.conf).
> > 
> > Or changing all pg_pconnect calls to pg_connect should solve your
> > problem.
> 
> I tried with pg_connect and pg_pconnect, but maybe I should restart all 
> webservers afterwards. I'll test this again.
> 
> Do I assume correctly that if I have a large percentage of "idle" 
> postgresql processes I may lower num_init_children and raise max_pool?

If your web application connect to PostgreSQL as all same user, say
"nobody", raising max_pool will not benefit at all. Actually in this
case max_pool = 1 is sufficiant. However since max_pool slot eat very
little memory, you might want to leave as it is.

Changing num_init_children will affect the total throughput. In
theory, lowering num_init_children will decrease the load of
PostgreSQL but increase the chance for pg_connect waiting for next
available pgpool's child process. Increasing num_init_children will
have opposite effect. So there must be a sweet spot for
num_init_children. I suggest you play around several num_init_children
settings seeking for the sweet spot.
--
Tatsuo Ishii