Received: from malur.postgresql.org ([217.196.149.56])
 by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from
 <pgsql-docs-owner+M7979=pgsql+2Ddocs=arkaria.postgresql.org@postgresql.org>)
 id 1WaUvZ-0005NR-Fx
 for pgsql-docs@arkaria.postgresql.org; Wed, 16 Apr 2014 18:51:21 +0000
Received: from localhost ([127.0.0.1] helo=postgresql.org)
 by malur.postgresql.org with smtp (Exim 4.80) (envelope-from
 <pgsql-docs-owner+M7979=pgsql+2Ddocs=arkaria.postgresql.org@postgresql.org>)
 id 1WaUvY-0003DX-Ve
 for pgsql-docs@arkaria.postgresql.org; Wed, 16 Apr 2014 18:51:21 +0000
Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29])
 by malur.postgresql.org with esmtp (Exim 4.80)
 (envelope-from <bruce@momjian.us>) id 1WaUvY-0003DR-DS
 for pgsql-docs@postgresql.org; Wed, 16 Apr 2014 18:51:20 +0000
Received: from momjian.us ([72.94.173.45])
 by magus.postgresql.org with esmtp (Exim 4.80)
 (envelope-from <bruce@momjian.us>) id 1WaUvV-0001iS-GW
 for pgsql-docs@postgresql.org; Wed, 16 Apr 2014 18:51:20 +0000
Received: from bruce by momjian.us with local (Exim 4.72)
 (envelope-from <bruce@momjian.us>)
 id 1WaUvT-0000Oz-3L; Wed, 16 Apr 2014 14:51:15 -0400
Date: Wed, 16 Apr 2014 14:51:15 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Fujii Masao <masao.fujii@gmail.com>
Cc: Marko Tiikkaja <marko@joh.to>, pgsql-docs <pgsql-docs@postgresql.org>
Subject: Re: hot_standby_feedback and max_standby_archive_delay
Message-ID: <20140416185115.GI7443@momjian.us>
References: <52D86D65.5010000@joh.to>
 <CAHGQGwFnnw0sBYh6=osF7_A+uTyUC5=-56hrJv6jvYb=C4hhbQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="k4f25fnPtRuIRUb3"
Content-Disposition: inline
In-Reply-To: 
 <CAHGQGwFnnw0sBYh6=osF7_A+uTyUC5=-56hrJv6jvYb=C4hhbQ@mail.gmail.com>
User-Agent: Mutt/1.5.20 (2009-06-14)
X-Pg-Spam-Score: -2.6 (--)
List-Archive: <http://archives.postgresql.org/pgsql-docs>
List-Help: <mailto:majordomo@postgresql.org?body=help>
List-ID: <pgsql-docs.postgresql.org>
List-Owner: <mailto:pgsql-docs-owner@postgresql.org>
List-Post: <mailto:pgsql-docs@postgresql.org>
List-Subscribe: <mailto:majordomo@postgresql.org?body=sub%20pgsql-docs>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-docs>
X-Mailing-List: pgsql-docs
Precedence: bulk
Sender: pgsql-docs-owner@postgresql.org


--k4f25fnPtRuIRUb3
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Mon, Feb  3, 2014 at 01:08:44AM +0900, Fujii Masao wrote:
> On Fri, Jan 17, 2014 at 8:38 AM, Marko Tiikkaja <marko@joh.to> wrote:
> > Hi,
> >
> > Myself and others found this statement in the documentation about $SUBJECT
> > very confusing: "max_standby_archive_delay must be kept large in this case,
> > because delayed WAL files might already contain entries that conflict with
> > the desired standby queries.".  After a chat with Andres I've tried to make
> > it clearer what said statement tries to convey.
> >
> > Did I succeed?
> 
> Don't we need to increase also max_standby_streaming_delay
> in the case that you mentioned in the patch? When the standby
> successfully reconnects to the master, lots of WAL files would
> be streamed and they might already have WAL entries that
> conflict with standby queries. No?

I have developed the attached doc patch to improve the wording on this
topic.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + Everyone has their own god. +

--k4f25fnPtRuIRUb3
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment; filename="streaming.diff"

diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml
new file mode 100644
index ecb51c4..39d7467
*** a/doc/src/sgml/high-availability.sgml
--- b/doc/src/sgml/high-availability.sgml
*************** if (!triggered)
*** 1889,1897 ****
      situation will be no worse than if the standby queries were running
      directly on the primary server, and you are still getting the benefit of
      off-loading execution onto the standby.
!     <varname>max_standby_archive_delay</> must be kept large in this case,
!     because delayed WAL files might already contain entries that conflict with
!     the desired standby queries.
     </para>
  
     <para>
--- 1889,1902 ----
      situation will be no worse than if the standby queries were running
      directly on the primary server, and you are still getting the benefit of
      off-loading execution onto the standby.
!     If standby servers connect and disconnect frequently, you
!     might want to make adjustments to handle the period when
!     <varname>hot_standby_feedback</> feedback is not being provided.
!     For example, consider increasing <varname>max_standby_archive_delay</>
!     so that queries are not rapidly cancelled by conflicts in WAL archive
!     files during disconnected periods.  You should also consider increasing
!     <varname>max_standby_streaming_delay</> to avoid rapid cancellations
!     by newly-arrived streaming WAL entries after reconnection.
     </para>
  
     <para>

--k4f25fnPtRuIRUb3
Content-Type: text/plain
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0


-- 
Sent via pgsql-docs mailing list (pgsql-docs@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-docs

--k4f25fnPtRuIRUb3--