Received: from renoir.op.net (root@renoir.op.net [209.152.193.4])

by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA29087

for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 10:31:08 -0400 (EDT)

Received: from hub.org (hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.3 $) with ESMTP id KAA27535 for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 10:19:47 -0400 (EDT)

Received: from hub.org (hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.4 $) with ESMTP id KAA27535 for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 10:19:47 -0400 (EDT)

Received: from localhost (majordom@localhost)

by hub.org (8.9.3/8.9.3) with SMTP id KAA30328;

Tue, 19 Oct 1999 10:12:10 -0400 (EDT)

Received: from renoir.op.net (root@renoir.op.net [209.152.193.4])

by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id VAA28130

for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 21:25:26 -0400 (EDT)

Received: from hub.org (hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.3 $) with ESMTP id VAA10512 for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 21:15:28 -0400 (EDT)

Received: from hub.org (hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.4 $) with ESMTP id VAA10512 for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 21:15:28 -0400 (EDT)

Received: from localhost (majordom@localhost)

by hub.org (8.9.3/8.9.3) with SMTP id VAA50745;

Tue, 19 Oct 1999 21:07:23 -0400 (EDT)

regards, tom lane

From pgsql-hackers-owner+M3455@postgresql.org Fri Jan 19 13:18:12 2001

Received: from mail.postgresql.org (webmail.postgresql.org [216.126.85.28])

by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id NAA02092

for <pgman@candle.pha.pa.us>; Fri, 19 Jan 2001 13:18:12 -0500 (EST)

Received: from mail.postgresql.org (webmail.postgresql.org [216.126.85.28])

by mail.postgresql.org (8.11.1/8.11.1) with SMTP id f0JIFJ037872;

Fri, 19 Jan 2001 13:15:19 -0500 (EST)

(envelope-from pgsql-hackers-owner+M3455@postgresql.org)

Received: from sectorbase2.sectorbase.com ([208.48.122.131])

by mail.postgresql.org (8.11.1/8.11.1) with ESMTP id f0JI7V036780

for <pgsql-hackers@postgreSQL.org>; Fri, 19 Jan 2001 13:07:31 -0500 (EST)

(envelope-from vmikheev@SECTORBASE.COM)

Received: by sectorbase2.sectorbase.com with Internet Mail Service (5.5.2653.19)

id <DG1W4LRZ>; Fri, 19 Jan 2001 09:46:14 -0800

Message-ID: <8F4C99C66D04D4118F580090272A7A234D329F@sectorbase1.sectorbase.com>

From: "Mikheev, Vadim" <vmikheev@SECTORBASE.COM>

To: "'Tom Lane'" <tgl@sss.pgh.pa.us>, Bruce Momjian <pgman@candle.pha.pa.us>

Cc: pgsql-hackers@postgresql.org

Subject: RE: [HACKERS] Possible performance improvement: buffer replacemen

t policy

Date: Fri, 19 Jan 2001 10:07:27 -0800

MIME-Version: 1.0

X-Mailer: Internet Mail Service (5.5.2653.19)

Content-Type: text/plain;

charset="iso-8859-1"

Precedence: bulk

Sender: pgsql-hackers-owner@postgresql.org

Status: OR

> > Tom, did we ever test this? I think we did and found that

> > it was the same or worse, right?

>

> I tried it and didn't see any noticeable improvement on the particular

> test case I was using, so I got discouraged and didn't pursue the idea

> further. I'd like to come back to it someday, though.

I don't know how much useful could be LRU-2 but with WAL we should try

to reuse undirty free buffers first, not dirty ones, just to postpone

writes as long as we can. (BTW, this is what Oracle does.)

So, we probably should put new free dirty buffer just before first

undirty one in LRU.

Vadim