Re: Sync Rep Design
Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
To: Simon Riggs <simon@2ndQuadrant.com>
Cc: Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>, Dimitri Fontaine <dimitri@2ndQuadrant.fr>, greg@2ndQuadrant.com, Josh Berkus <josh@postgresql.org>, Hannu Krosing <hannu@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org
Date: 2011-01-01T19:29:45Z
Lists: pgsql-hackers
On 01.01.2011 19:03, Simon Riggs wrote: > On Sat, 2011-01-01 at 17:37 +0100, Stefan Kaltenbrunner wrote: >> On 01/01/2011 05:28 PM, Dimitri Fontaine wrote: >>> Stefan Kaltenbrunner<stefan@kaltenbrunner.cc> writes: >>>> well you keep saying that but to be honest I cannot really even see a >>>> usecase for me - what is "only a random one of a set of servers is sync at >>>> any time and I don't really know which one". >>> >>> It looks easy enough to get to know which one it is. Surely the primary >>> knows and could update something visible through a system view for >>> users? This as been asked for before and I was thinking there was a >>> consensus on this. >> >> well as jeff janes already said - anything that requires the master to >> still exist is not useful for a desaster. > > Nobody has suggested that the master needs to still exist after a > disaster. Dimitri just did, see above. I agree it's not very useful. I don't think there's any other solution to knowing which standby is ahead than connect to both standbys and ask how far each is. I don't see a problem with that, whatever middleware handles the failover and STONITH etc. should be able to do that too. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com