Skip site navigation (1) Skip section navigation (2)

Re: synchronous_commit and remote_write

From: Simon Riggs <simon(at)2ndQuadrant(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Bruce Momjian <bruce(at)momjian(dot)us>, Aidan Van Dyk <aidan(at)highrise(dot)ca>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: synchronous_commit and remote_write
Date: 2012-05-09 14:02:23
Message-ID: CA+U5nMJEjUebk9unkbDJHCBDftg=9HV9aRz6v8a5aybxi1w0_Q@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-hackers
On 9 May 2012 13:48, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Wed, May 9, 2012 at 7:29 AM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
>> Let me point out that our documentation says nothing about it being
>> written to the kernel --- it just says "has received the commit record
>> of the transaction to memory."
>
> Maybe remote_receive would be better.  If we're actually writing it
> back to the kernel before acknowledging the commit, that seems like an
> implementation defect more than anything else, since it does not -
> AFAICS - provide any additional, useful guarantee.

It does provide an additional guarantee, but I accept you personally
may not find that useful.

If the docs don't describe it well enough, then we can change the docs.


> Another thing I've been wondering is whether, perhaps, we ought to
> keep synchronous_commit tri-valued: on/local/off, and have a separate
> GUC for synchronous_replication_mode.  It's a bit arbitrary that "on"
> happens to mean remote fsync rather than remote write/receive.

You mean the way it originally was? I would agree.

-- 
 Simon Riggs                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

In response to

Responses

pgsql-hackers by date

Next:From: Tom LaneDate: 2012-05-09 14:31:12
Subject: "pgstat wait timeout" just got a lot more common on Windows
Previous:From: Pavel StehuleDate: 2012-05-09 13:33:01
Subject: enhanced error fields

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group