[Pgpool-general] Help in pgpool loadbalancing

[Steven Crandell]

As far as I understand things, you would still be seeing
inserts/updates/deletes on backend node 0 even if it is weighted to 0
because pgpool considers this node to be the master and therefore the only
node capable of accepting new data.
e.g. the weight of a node in a master/slave configuration only determines
the number of selects being sent to slaves.

I run a 3 node cluster with mammoth replicator replicating data from master
to slaves and have set up pgpool with node 0 set to weight 0 and the other
two slaves set to 0.5.

My intention with this configuration is for the master to only ever receive
INSERT/UPDATE/DELETE statement and to have all SELECT statements sent to the
two slaves in a 50%/50% split.  Thereby, the cluster is able to scale up to
the point where the number of writes exceed the capabilities of the master
without wasting master system resources on reads.

So far this setup seems to work but I must admit that this configuration
does not seem to be clearly documented anywhere that I could find despite it
being a fairly typical need for a 3rd party replication solutions.

If my assumptions about this are wrong I hope someone with more experience
in this area will pipe up.

-s

On Sun, Jul 19, 2009 at 11:29 AM, Glyn Astill <glynastill at yahoo.co.uk>wrote:

>
> > From: Nimesh Satam <nimesh.satam at gmail.com>
> > Subject: [Pgpool-general] Help in pgpool loadbalancing
> > To: pgpool-general at pgfoundry.org
> > Date: Sunday, 19 July, 2009, 4:04 PM
> > Hi,
> >
> > Can anybody highlight how queries can be loadbalanced
> > in pgpool? How does backend_weight0 means and what happens
> > if the value for this parameter is set to '0'.
> >
> > I need to use this parameter in the given below way:
> >
> >
> > Set backend_weight0 = 0
> >
> > So as no queries go to the first node. But in our
> > usage we do see queries coming to the node for whom the
> > parameter is set to 0. We are using pgpool in master/slave
> > mode, with no connection caching.
> >
> >
>
> If you do not want any queries to go through to the first node, why not
> just remove it completely from the config?
>
>
>
> _______________________________________________
> Pgpool-general mailing list
> Pgpool-general at pgfoundry.org
> http://pgfoundry.org/mailman/listinfo/pgpool-general
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://pgfoundry.org/pipermail/pgpool-general/attachments/20090719/54372615/attachment.html>