pg.ddx.io  pgsql-hackers@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Joshua D. Drake <jd@commandprompt.com>
To: Andres Freund <andres@2ndquadrant.com>
Cc: KONDO Mitsumasa <kondo.mitsumasa@lab.ntt.co.jp>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Heikki Linnakangas <hlinnakangas@vmware.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Improvement of checkpoint IO scheduler for stable transaction responses
Date: Thu, 04 Jul 2013 08:35:32 -0700
Message-ID: <51D59644.2070005@commandprompt.com> (raw)
In-Reply-To: <20130704130555.GA1403@awork2.anarazel.de>
References: <51BEB6F5.7070907@lab.ntt.co.jp>
	<51C40EF4.1080201@lab.ntt.co.jp>
	<51C9D03B.10107@vmware.com>
	<CA+TgmoZ+ofyg4e+hRBTnnfrC7M2ATX-Pg0k4AtyHx60A+_DFhQ@mail.gmail.com>
	<51C9FD5C.5050706@vmware.com>
	<CA+TgmoZj-0CFLbjceMtgi1t_=hpfe9z8uSa+D0g77sNYcFy04w@mail.gmail.com>
	<51CD873A.5070705@lab.ntt.co.jp>
	<51D3DE55.6030901@lab.ntt.co.jp>
	<CA+TgmoZsh0zRdLoPh+PaGswMKqHRLZcAb89O+XRQLhSsjYOaYg@mail.gmail.com>
	<51D56A5B.3050504@lab.ntt.co.jp>
	<20130704130555.GA1403@awork2.anarazel.de>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-hackers>


On 07/04/2013 06:05 AM, Andres Freund wrote:

>>> Presumably the smaller segsize is better because we don't
>>> completely stall the system by submitting up to 1GB of io at once. So,
>>> if we were to do it in 32MB chunks and then do a final fsync()
>>> afterwards we might get most of the benefits.
>> Yes, I try to test this setting './configure --with-segsize=0.03125' tonight.
>> I will send you this test result tomorrow.
>

I did testing on this a few years ago, I tried with 2MB segments over 
16MB thinking similarly to you. It failed miserably, performance 
completely tanked.

JD

-- 
Command Prompt, Inc. - http://www.commandprompt.com/  509-416-6579
PostgreSQL Support, Training, Professional Services and Development
High Availability, Oracle Conversion, Postgres-XC, @cmdpromptinc
For my dreams of your image that blossoms
    a rose in the deeps of my heart. - W.B. Yeats


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



view thread (63+ messages)  latest in thread

Message-ID: <51D59644.2070005@commandprompt.com>
Permalink:  ../51D59644.2070005@commandprompt.com/
Also on:    postgresql.org/message-id/51D59644.2070005@commandprompt.com

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-hackers@postgresql.org
  Cc: jd@commandprompt.com, andres@2ndquadrant.com, kondo.mitsumasa@lab.ntt.co.jp, robertmhaas@gmail.com, hlinnakangas@vmware.com
  Subject: Re: Improvement of checkpoint IO scheduler for stable transaction responses
  In-Reply-To: <51D59644.2070005@commandprompt.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox