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: Tue, 24 Apr 2012 10:17:14 +0200
Message-ID: <20120424081714.GA12034@feivel.credativ.lan> (raw)
In-Reply-To: <4F95613B.2030904@cybertec.at>
References: <20120410145501.GA11554@feivel.credativ.lan>
<4F847453.9060200@cybertec.at>
<20120416024636.GA4536@feivel.credativ.lan>
<4F8B9F19.3040403@cybertec.at>
<20120416160448.GA9968@feivel.credativ.lan>
<4F8C544F.4080708@cybertec.at>
<20120417035208.GA5465@feivel.credativ.lan>
<4F8CEB5A.100@cybertec.at>
<20120417044819.GA9043@feivel.credativ.lan>
<4F95613B.2030904@cybertec.at>
> OK, I will implement #2. Another question popped up: what to do
> with FETCH ALL? The current readahead window size or temporarily
> bumping it to say some tens of thousands can be used. We may not
> know how much is the "all records". This, although lowers performance,
> saves memory.
I would say doing a large fetch in two or three batches won't cost too much in
terms of performance.
> Please, don't apply this patch yet. I discovered a rather big hole
> that can confuse the cursor position tracking if you do this:
> ...
> That will also need a new round of review. Sorry for that.
No problem, better to find it now instead of after release.
Anyway, I moved the patch to 2012-next (I hope I did it correctly) so 2012-1
can be closed. Let's try to get this patch done in the next commit fest.
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
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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: <20120424081714.GA12034@feivel.credativ.lan>
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