Re: Standalone synchronous master
Stephen Frost <sfrost@snowman.net>
From: Stephen Frost <sfrost@snowman.net>
To: Josh Berkus <josh@agliodbs.com>
Cc: Andres Freund <andres@2ndquadrant.com>,
"Joshua D. Drake" <jd@commandprompt.com>,
Tom Lane <tgl@sss.pgh.pa.us>, Kevin Grittner <kgrittn@ymail.com>,
Bruce Momjian <bruce@momjian.us>,
Heikki Linnakangas <hlinnakangas@vmware.com>,
Simon Riggs <simon@2ndQuadrant.com>,
Rajeev rastogi <rajeev.rastogi@huawei.com>,
"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2014-01-08T23:18:26Z
Lists: pgsql-hackers
Josh, * Josh Berkus (josh@agliodbs.com) wrote: > > I'm aware, my point was simply that we should state, up-front in > > 25.2.7.3 *and* where we document synchronous_standby_names, that it > > requires at least three servers to be involved to be a workable > > solution. > > It's a workable solution with 2 servers. That's a "low-availability, > high-integrity" solution; the user has chosen to double their risk of > not accepting writes against never losing a write. That's a perfectly > valid configuration, and I believe that NTT runs several applications > this way. I really don't agree with that when the standby going offline can take out the master. Note that I didn't say we shouldn't allow it, but I don't think we should accept that it's a real-world solution. > I really think that demand for auto-degrade is coming from users who > don't know what sync rep is for in the first place. The fact that other > vendors are offering auto-degrade as a feature instead of the ginormous > foot-gun it is adds to the confusion, but we can't help that. Do you really feel that a WARNING and increasing the docs to point out that three systems are necessary, particularly under the 'high availability' documentation and options, is a bad idea? I fail to see how that does anything but clarify the use-case for our users. Thanks, Stephen