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Date: Thu, 15 May 2008 11:52:32 -0400
From: Alvaro Herrera <alvherre@commandprompt.com>
To: Matthew Wakeling <matthew@flymine.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: I/O on select count(*)
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Matthew Wakeling wrote:

Aside from the rest of commentary, a slight clarification:

> So, as I understand it, Postgres works like this:
>
> 1. You begin a transaction. Postgres writes an entry into pg_clog.

Starting a transaction does not write anything to pg_clog.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.