Re: Disk Performance Problem on Large DB

From: Samuel Stearns <SStearns(at)internode(dot)com(dot)au>
To: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
Cc: Jonathan Hoover <jhoover(at)yahoo-inc(dot)com>, "pgsql-admin(at)postgresql(dot)org" <pgsql-admin(at)postgresql(dot)org>, Kenneth Marshall <ktm(at)rice(dot)edu>
Subject: Re: Disk Performance Problem on Large DB
Date: 2010-11-05 03:44:57
Message-ID: 68B59BEDCD36854AADBDF17E91B2937A0783A71E3F@EXCHMAIL.staff.internode.com.au
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Yep!

Coming from previous Oracle job into Postgres, discovering the transactable stuff, is indeed, pretty cool.

-----Original Message-----
From: Scott Marlowe [mailto:scott(dot)marlowe(at)gmail(dot)com]
Sent: Friday, 5 November 2010 2:12 PM
To: Samuel Stearns
Cc: Jonathan Hoover; pgsql-admin(at)postgresql(dot)org; Kenneth Marshall
Subject: Re: [ADMIN] Disk Performance Problem on Large DB

On Thu, Nov 4, 2010 at 9:33 PM, Samuel Stearns
<SStearns(at)internode(dot)com(dot)au> wrote:
> TRUNCATE doesn't generate any rollback data, which makes it lightning fast. It just de-allocates the data pages used by the table.

Also truncate, like nearly everything in pgsql, can be rolled back. I
still remember showing my oracle co-dbas in my last job freak out when
I showed them things like

begin;
update table yada...
truncate table;
rollback;

or
begin;
drop index xyz;
explain select ...
rollback;

transactable everything is pretty cool. (note database and tablespace
craete / drop are the only things that aren't transactable, which
makes some sense.)

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