Re: ECPG FETCH readahead

From: Michael Meskes <meskes(at)postgresql(dot)org>
To: Boszormenyi Zoltan <zb(at)cybertec(dot)at>
Cc: Noah Misch <noah(at)leadboat(dot)com>, Michael Meskes <meskes(at)postgresql(dot)org>, Robert Haas <robertmhaas(at)gmail(dot)com>, PG Hackers <pgsql-hackers(at)postgresql(dot)org>, Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>
Subject: Re: ECPG FETCH readahead
Date: 2012-04-24 08:17:14
Message-ID: 20120424081714.GA12034@feivel.credativ.lan
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> 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)
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