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To: Steve Crawford <scrawford@pinpointresearch.com>
cc: Lukasz Brodziak <lukasz.brodziak@gmail.com>, pgsql-admin@postgresql.org
Subject: Re: pg_attribute file in PostgreSQL 9.0 
In-reply-to: <4F577217.3080204@pinpointresearch.com> 
References: 
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Comments: In-reply-to Steve Crawford <scrawford@pinpointresearch.com>
	message dated "Wed, 07 Mar 2012 06:35:03 -0800"
Date: Wed, 07 Mar 2012 10:01:12 -0500
Message-ID: <7061.1331132472@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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Steve Crawford <scrawford@pinpointresearch.com> writes:
> On 03/07/2012 05:14 AM, Lukasz Brodziak wrote:
>> I have a question regarding pg_attribute. In which file it is stored
>> because the relfilenode for it shows 0 and file 1249 isn't present in
>> the folder.

> select pg_relation_filepath('pg_attribute');

>  From the docs, relfilenode is:
> "Name of the on-disk file of this relation; zero means this is a 
> "mapped" relation whose disk file name is determined by low-level state"

> However the meaning "mapped relation" and "low-level state" are 
> difficult to divine from the docs. Go with the function.

Or use pg_relation_filenode() if you want the result of the mapping.

			regards, tom lane