pg.ddx.io  pgsql-performance@postgresql.org mailing list archive  

help / color / mirror / Atom feed

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Pavan Deolasee <pavan.deolasee@gmail.com>
Cc: Gauri Kanekar <meetgaurikanekar@gmail.com>
Cc: Shane Ambler <pgsql@sheeky.biz>
Cc: Alvaro Herrera <alvherre@commandprompt.com>
Cc: Greg Smith <gsmith@gregsmith.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Replication Syatem
Date: Wed, 30 Apr 2008 10:46:28 -0400
Message-ID: <18684.1209566788@sss.pgh.pa.us> (raw)
In-Reply-To: <2e78013d0804300025j10567a82x5845ab8bc3d4f2a2@mail.gmail.com>
References: <7e4ba9550804280638ie81dc23w472785c83cd38fcf@mail.gmail.com>
	<Pine.GSO.4.64.0804290347560.20575@westnet.com>
	<7e4ba9550804290405i4c0d3a57x1640239c9995c13@mail.gmail.com>
	<20080429130204.GA5652@alvh.no-ip.org>
	<4817514A.3060704@Sheeky.Biz>
	<7e4ba9550804292229x82e74e5y355349866c72245c@mail.gmail.com>
	<2e78013d0804292237l4c74a166u4ab082901aa0804f@mail.gmail.com>
	<7e4ba9550804292239n668b1f01v59ad7ac6ca9e092b@mail.gmail.com>
	<2e78013d0804292343hd9d1c0lf93df68e559f9af3@mail.gmail.com>
	<7e4ba9550804292346r46aa55e7g6cf1f731b6be7d40@mail.gmail.com>
	<2e78013d0804300025j10567a82x5845ab8bc3d4f2a2@mail.gmail.com>

"Pavan Deolasee" <pavan.deolasee@gmail.com> writes:
> That's weird. With that fillfactor, you should have a very high
> percentage of HOT update ratio. It could be a very special case that
> we might be looking at.

He's testing

>> update table1 set delta1 = 100 where code/1000000 =999;

so all the rows being updated fall into a contiguous range of "code"
values.  If the table was loaded in such a way that those rows were
also physically contiguous, then the updates would be localized and
would very soon run out of freespace on those pages.

			regards, tom lane

view thread (48+ messages)  latest in thread

Message-ID: <18684.1209566788@sss.pgh.pa.us>
Permalink:  ../18684.1209566788@sss.pgh.pa.us/
Also on:    postgresql.org/message-id/18684.1209566788@sss.pgh.pa.us

copy link · copy postgr.es

reply

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-performance@postgresql.org
  Cc: tgl@sss.pgh.pa.us, pavan.deolasee@gmail.com, meetgaurikanekar@gmail.com, pgsql@sheeky.biz, alvherre@commandprompt.com, gsmith@gregsmith.com
  Subject: Re: Replication Syatem
  In-Reply-To: <18684.1209566788@sss.pgh.pa.us>

* 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