Re: Repeat posts - Mailing list pgsql-general

"Raymond O'Donnell" <rod@iol.ie> writes:
> Is it just me? :-) from time to time I get repeat broadcasts from
> various PG mailing lists - posts that I've already received several days
> previously are sent again.

There are people on the lists with broken mail software that resubmits
old traffic back to the list.  The listserv has some defenses against
that --- it's supposed to reject message-ids that it's seen before ---
but count on Microsoft to mangle mail messages badly enough to get
around that.

The latest example, which I too just got, looks on inspection of the
headers to be blamable on <wavey@intercom.net>.  The time delay suggests
it was held for moderation, so maybe the software *did* recognize it as
a dup and it was moderator error to let it through.

            regards, tom lane

------- Forwarded Message

Return-Path: pgsql-general-owner+m118894@postgresql.org
Delivery-Date: Fri Aug 17 08:31:02 2007
Received: from postgresql.org (postgresql.org [200.46.204.71])
    by sss.pgh.pa.us (8.14.1/8.14.1) with ESMTP id l7HCUw15003684
    for <tgl@sss.pgh.pa.us>; Fri, 17 Aug 2007 08:31:01 -0400 (EDT)
Received: from localhost (maia-1.hub.org [200.46.204.191])
    by postgresql.org (Postfix) with ESMTP id E647F9FB91B;
    Fri, 17 Aug 2007 09:17:47 -0300 (ADT)
Received: from postgresql.org ([200.46.204.71])
 by localhost (mx1.hub.org [200.46.204.191]) (amavisd-maia, port 10024)
 with ESMTP id 12766-01-6; Fri, 17 Aug 2007 09:17:47 -0300 (ADT)
Received: from postgresql.org (postgresql.org [200.46.204.71])
    by postgresql.org (Postfix) with ESMTP id BAD949FC15F;
    Fri, 17 Aug 2007 09:04:42 -0300 (ADT)
Received: from localhost (maia-5.hub.org [200.46.204.182])
    by postgresql.org (Postfix) with ESMTP id 2B8409F983B
    for <pgsql-general-postgresql.org@postgresql.org>; Tue, 14 Aug 2007 21:32:16 -0300 (ADT)
Received: from postgresql.org ([200.46.204.71])
 by localhost (mx1.hub.org [200.46.204.182]) (amavisd-maia, port 10024)
 with ESMTP id 15822-01 for <pgsql-general-postgresql.org@postgresql.org>;
 Tue, 14 Aug 2007 21:32:06 -0300 (ADT)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.5
Received: from mx3.hub.org (206-223-169-73.beanfield.net [206.223.169.73])
    by postgresql.org (Postfix) with ESMTP id B3CD39F9838
    for <pgsql-general@postgresql.org>; Tue, 14 Aug 2007 21:32:10 -0300 (ADT)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.5
Received: from avscan-cl-a.dmv-online.net (avscan-cl-a.dmv-online.net [216.240.97.7])
    by mx3.hub.org (Postfix) with ESMTP id 329CC37CC65
    for <pgsql-general@postgresql.org>; Tue, 14 Aug 2007 21:32:10 -0300 (ADT)
Received: from avscan-cl-a.dmv-online.net (localhost.dmv-online.net [127.0.0.1])
    by avscan-cl-a.dmv-online.net (8.13.8/8.13.6) with ESMTP id l7ENS25C060794;
    Tue, 14 Aug 2007 19:28:02 -0400 (EDT)
    (envelope-from postmaster@avscan-cl-a.dmv-online.net)
Received: (from root@localhost)
    by avscan-cl-a.dmv-online.net (8.13.8/8.13.6/Submit) id l7ENS2H9060793;
    Tue, 14 Aug 2007 19:28:02 -0400 (EDT)
    (envelope-from postmaster)
Received: from mx2.hub.org (mx2.hub.org [200.46.204.254])
    by mgw-cl-a.dmv.com (8.13.6/8.13.6) with ESMTP id l7EJ2gc8017686
    for <wavey@intercom.net>; Tue, 14 Aug 2007 15:02:48 -0400 (EDT)
    (envelope-from pgsql-general-owner+M118585@postgresql.org)
Received: from postgresql.org (postgresql.org [200.46.204.71])
    by mx2.hub.org (Postfix) with ESMTP id C20728B367E;
    Tue, 14 Aug 2007 16:02:40 -0300 (ADT)
Received: from localhost (maia-5.hub.org [200.46.204.182])
    by postgresql.org (Postfix) with ESMTP id 826889FA117
    for <pgsql-general-postgresql.org@postgresql.org>; Tue, 14 Aug 2007 15:59:54 -0300 (ADT)
Received: from postgresql.org ([200.46.204.71])
 by localhost (mx1.hub.org [200.46.204.182]) (amavisd-maia, port 10024)
 with ESMTP id 11907-01 for <pgsql-general-postgresql.org@postgresql.org>;
 Tue, 14 Aug 2007 15:59:47 -0300 (ADT)
X-Greylist: domain auto-whitelisted by SQLgrey-1.7.5
Received: from rv-out-0910.google.com (rv-out-0910.google.com [209.85.198.188])
    by postgresql.org (Postfix) with ESMTP id B385D9FA0A7
    for <pgsql-general@postgresql.org>; Tue, 14 Aug 2007 15:59:48 -0300 (ADT)
Received: by rv-out-0910.google.com with SMTP id f1so1312494rvb
        for <pgsql-general@postgresql.org>; Tue, 14 Aug 2007 11:59:43 -0700 (PDT)
DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed;
        d=gmail.com; s=beta;

h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references;

b=HBo76On4+5ImPvzBDlrWomsojLb/BaU/+0YrO09J55NTtUddXNyU9Ju+wW7DuUC2fSxsZmPlzrc4yPGJ9xNcbP8vfoqYqnxy3U2N21tBOLCWIAdQCQTBj+vCHQG7U+ttJW1ITm+og8OXWEE3pHnFwoDo8RInExAwhniSaMid+TM=
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=beta;

h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references;

b=LYh4TMuVtHjVZ1EhNn3ijCh7+wx14AR7kHw9FHGjN+APD15ukJCqE7s/IvfmhckyLLyIWPcKunCrDFg+ecOmqo6lFvbPduvOOtRAwkkSztMh+265/nomp272yPWYZk/4UOSxHJNOGzsjJVuga0Gt+/CYozQCKHXj9mYtTg39pA8=
Received: by 10.141.34.12 with SMTP id m12mr2791837rvj.1187117983510;
        Tue, 14 Aug 2007 11:59:43 -0700 (PDT)
Received: by 10.141.98.12 with HTTP; Tue, 14 Aug 2007 11:59:43 -0700 (PDT)
Message-ID: <dcc563d10708141159y5aee7450qca148623e1ab0287@mail.gmail.com>
Date: Tue, 14 Aug 2007 13:59:43 -0500
From: "Scott Marlowe" <scott.marlowe@gmail.com>
To: RPK <rpk.general@gmail.com>
Subject: Re: [GENERAL] MVCC cons
X-Magic-MPP: 000002ff46c21624
Cc: pgsql-general@postgresql.org
In-Reply-To: <12149505.post@talk.nabble.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
References: <12149505.post@talk.nabble.com>
X-Virus-Scanned: Maia Mailguard 1.0.1
X-Mailing-List: pgsql-general
Precedence: bulk
X-Virus-Scanned: Maia Mailguard 1.0.1
X-Mailing-List: pgsql-general
List-Archive: <http://archives.postgresql.org/pgsql-general>
List-Help: <mailto:majordomo@postgresql.org?body=help>
List-ID: <pgsql-general.postgresql.org>
List-Owner: <mailto:pgsql-general-owner@postgresql.org>
List-Post: <mailto:pgsql-general@postgresql.org>
List-Subscribe: <mailto:majordomo@postgresql.org?body=sub%20pgsql-general>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-general>
Precedence: bulk
Sender: pgsql-general-owner@postgresql.org

On 8/14/07, RPK <rpk.general@gmail.com> wrote:
>
> I want to know whether MVCC has cons also. Is it heavy on resources? How
> PGSQL MVCC relates with SQL Server 2005 new Snapshot Isolation.

Of course it does.  There ain't no such thing as a free lunch, after all.

PostgreSQL's mvcc implementation means that a row that gets updated a
lot may have many dead rows in the database, and if you don't run
vacuum often enough, or have enough space allocated in your free space
map, your tables can become bloated.

In a worst case scenario, a highly updated table may get so big that
normal vacuuming cannot salvage it and you would have to either
reindex or perform a vacuum full on it.

---------------------------(end of broadcast)---------------------------
TIP 4: Have you searched our list archives?

               http://archives.postgresql.org/

---------------------------(end of broadcast)---------------------------
TIP 4: Have you searched our list archives?

               http://archives.postgresql.org/

------- End of Forwarded Message