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 <[email protected]>wrote: > > > From: Nimesh Satam <[email protected]> > > Subject: [Pgpool-general] Help in pgpool loadbalancing > > To: [email protected] > > 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 > [email protected] > http://pgfoundry.org/mailman/listinfo/pgpool-general >
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