From: Michael Meskes <meskes@postgresql.org>
To: Boszormenyi Zoltan <zb@cybertec.at>
Cc: Noah Misch <noah@leadboat.com>
Cc: Michael Meskes <meskes@postgresql.org>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: PG Hackers <pgsql-hackers@postgresql.org>
Cc: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Cc: Bruce Momjian <bruce@momjian.us>
Subject: Re: ECPG FETCH readahead
Date: Mon, 16 Apr 2012 18:04:48 +0200
Message-ID: <20120416160448.GA9968@feivel.credativ.lan> (raw)
In-Reply-To: <4F8B9F19.3040403@cybertec.at>
References: <20120407155042.GB11987@tornado.leadboat.com>
<20120408142501.GA21513@feivel.credativ.lan>
<4F81BE55.1010904@cybertec.at>
<20120408173859.GA4915@feivel.credativ.lan>
<4F83E2B9.3030302@cybertec.at>
<20120410143722.GC6129@tornado.leadboat.com>
<20120410145501.GA11554@feivel.credativ.lan>
<4F847453.9060200@cybertec.at>
<20120416024636.GA4536@feivel.credativ.lan>
<4F8B9F19.3040403@cybertec.at>
On Mon, Apr 16, 2012 at 06:24:57AM +0200, Boszormenyi Zoltan wrote:
> Yes, just like when the readahead window set to 256, FETCH 1024
> will iterate through 4 windows or FETCH 64 iterates through the
> same window 4 times. This is the idea behind the "readahead window".
Really? It's definitely not the idea behind FETCH 1024. Using the same window 4
times for FETCH 64 is the idea though, I agree.
> How about allowing the readahead window to be resized for the
> non-decorated case if the runtime encounters FETCH N and N is
> greater than the previous window?
To be resized by what? IMO a FETCH N should always be a FETCH N, no matter
what, i.e. if the readahead window is larger, use it, but even if it's smaller
we should still fetch N at the same time.
Michael
--
Michael Meskes
Michael at Fam-Meskes dot De, Michael at Meskes dot (De|Com|Net|Org)
Michael at BorussiaFan dot De, Meskes at (Debian|Postgresql) dot Org
Jabber: michael.meskes at googlemail dot com
VfL Borussia! Força Barça! Go SF 49ers! Use Debian GNU/Linux, PostgreSQL
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: meskes@postgresql.org, zb@cybertec.at, noah@leadboat.com, robertmhaas@gmail.com, heikki.linnakangas@enterprisedb.com, bruce@momjian.us
Subject: Re: ECPG FETCH readahead
In-Reply-To: <20120416160448.GA9968@feivel.credativ.lan>
* 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