On Wed, 2011-10-05 at 11:44 +0100, Thom Brown wrote: > On 5 October 2011 11:40, Guillaume Lelarge <guilla...@lelarge.info> wrote: > > On Wed, 2011-10-05 at 12:22 +0200, Guillaume Lelarge wrote: > >> On Wed, 2011-10-05 at 10:13 +0100, Thom Brown wrote: > >> > On 5 October 2011 10:05, Guillaume Lelarge <guilla...@lelarge.info> > >> > wrote: > >> > > On Wed, 2011-10-05 at 09:38 +0100, Thom Brown wrote: > >> > >[...] > >> > >> This seems like it should be a very common setup, so does pgPool have > >> > >> provisioning for this, like having a 3rd pgPool to manage them > >> > >> somehow? > >> > >> > >> > > > >> > > No, it's not possible right now, and there's no discussion between > >> > > developers to do something like this (at least on pgpool-hackers). > >> > > >> > So no-one has ever configured pgPool to have true HA? Isn't there any > >> > kind of black magick trickery one can do with the existing config > >> > options to achieve this? > >> > > >> > >> I guess true HA really depends on your context. > >> > >> Say we have two data centers (DC1 and DC2), two PostgreSQL servers (PG1 > >> and PG2), and two pgpool servers (PGP1 and PGP2). I would have all users > >> access to the database through PGP1. Say that DC1 isn't available > >> anymore, what I would do is change the IPVS so that all users go through > >> PGP2, change PGP2 configuration so that it cannot access to PG1, and > >> make sure that PG2 is the new master. Which of course is not automatic, > >> there are a few steps that need manual work. > >> > >> But actually, what you are asking for is quite hard to have. > > I understand that MySQL cluster suite (or whatever it's called) has a > master controller which provides this somehow. >
Not sure how it works, but it would be interesting to know. > >> > So in load balancing mode, is backend_*0 regarded by pgPool to be the > >> > primary, or is pgPool clever and polls the servers to figure this out? > >> > > >> > >> You mean, in master_slave mode. AFAIR, yes, it is. But I'll check. > >> > > > > And I was wrong. At least when you first start pgpool. > > How does it then know where to direct write queries to? > At the beginning, it always sends the write queries to backend 0. -- Guillaume http://blog.guillaume.lelarge.info http://www.dalibo.com _______________________________________________ Pgpool-general mailing list Pgpool-general@pgfoundry.org http://pgfoundry.org/mailman/listinfo/pgpool-general