[Pgpool-general] Master/Slave Load Balancing Configuration

[Yoshiyuki Asaba]

Hi,

From: Ow Mun Heng <Ow.Mun.Heng at wdc.com>
Subject: Re: [Pgpool-general] Master/Slave Load Balancing Configuration
Date: Fri, 04 Jan 2008 17:06:36 +0800

> 
> On Fri, 2008-01-04 at 17:57 +0900, Yoshiyuki Asaba wrote:
> > From: Ow Mun Heng <Ow.Mun.Heng at wdc.com>
> > > Setup : 
> > > Slony 1 master, 1 slave - pg8.2.5, slony 1.12
> > > pgpool - 2.01
> > > OS : centos 4
> > > Goal : SLony for replication
> > > Pgpool for load balancing across multiple slaves+1master
> > ...
> > > listen_addresses = '*'
> > > port = 9999
> > > replication_mode = true
> > 
> > If you use Slony-I, you need to set replication_mode to false.
> 
> > Can you set the following setting?
> > 
> >   replication_mode = false
> >   master_slave_mode = true
> >   load_balance_mode = true
> >   backend_hostname0 = 'pgmaster'
> >   backend_port0 = 5432
> >   backend_weight0 = 0.2
> >   backend_hostname1 = 'pgslave1'
> >   backend_port1 = 5432
> >   backend_weight1 = 0.8
> 
> Actually, I did try this, (following the docs) but for the life of me, I
> was not able to see/determine if load balancing was actually
> happening.

I cannot reproduce it in my environment.

  % pgpool -n -d -f pgpool.conf &; sleep 5; psql -p 9999 -c 'select 1' postgres
  ...
  DEBUG: pid 28641: select_load_balancing_node: selected backend id is 1
  ...
  LOG:   pid 28641: statement: select 1; *** select slave node ***
  DEBUG: pid 28641: waiting for backend 0 completing the query
  DEBUG: pid 28641: read_kind_from_backend: read kind from 0 th backend T NUM_BACKENDS: 1
  DEBUG: pid 28641: pool_process_query: kind from backend: T
  DEBUG: pid 28641: read_kind_from_backend: read kind from 0 th backend D NUM_BACKENDS: 1
  DEBUG: pid 28641: pool_process_query: kind from backend: D
  DEBUG: pid 28641: read_kind_from_backend: read kind from 0 th backend C NUM_BACKENDS: 1
  DEBUG: pid 28641: pool_process_query: kind from backend: C

Can you show us debug log?

Regards,
--
Yoshiyuki Asaba
y-asaba at sraoss.co.jp


> 
> I did (more than) a few sample queries to see where I'm querying (eg:
> Same table, but the tables has different data _just_ to see where pgpool
> is sending the queries) but all I ever found was that all the queries
> were going into pgmaster.
> 
> The debug logs did not show anything which says otherwise either.
> 
> additionall "show pool status" also does not show anything interesting)
> 
> pgpool -h
> pgpool version 2.0.1(heemauli)
> 
> But I will give it the benefit of a doubt and retry again. Please tell
> me how to see that it is working. Many Thanks.