| From: | Florian Pflug <fgp(at)phlo(dot)org> |
|---|---|
| To: | Josh Berkus <josh(at)agliodbs(dot)com> |
| Cc: | Bruce Momjian <bruce(at)momjian(dot)us>, Andres Freund <andres(at)2ndquadrant(dot)com>, "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Hannu Krosing <hannu(at)2ndquadrant(dot)com>, MauMau <maumau307(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Kevin Grittner <kgrittn(at)ymail(dot)com>, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Rajeev rastogi <rajeev(dot)rastogi(at)huawei(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Standalone synchronous master |
| Date: | 2014-01-13 15:12:27 |
| Message-ID: | 0F82AD6E-7C4B-4BA6-B762-D42704A8D9C6@phlo.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Jan12, 2014, at 04:18 , Josh Berkus <josh(at)agliodbs(dot)com> wrote:
> Thing is, when we talk about auto-degrade, we need to determine things
> like "Is the replica down or is this just a network blip"? and take
> action according to the user's desired configuration. This is not
> something, realistically, that we can do on a single request. Whereas
> it would be fairly simple for an external monitoring utility to do:
>
> 1. decide replica is offline for the duration (several poll attempts
> have failed)
>
> 2. Send ALTER SYSTEM SET to the master and change/disable the
> synch_replicas.
>
> In other words, if we're going to have auto-degrade, the most
> intelligent place for it is in
> RepMgr/HandyRep/OmniPITR/pgPoolII/whatever. It's also the *easiest*
> place. Anything we do *inside* Postgres is going to have a really,
> really hard time determining when to degrade.
+1
This is also how 2PC works, btw - the database provides the building
blocks, i.e. PREPARE and COMMIT, and leaves it to a transaction manager
to deal with issues that require a whole-cluster perspective.
best regards,
Florian Pflug
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2014-01-13 15:16:42 | Where do we stand on 9.3 bugs? |
| Previous Message | Oleg Bartunov | 2014-01-13 14:30:27 | Re: nested hstore patch |