Re: Physical block structure in PostgreSQL - Mailing list pgsql-general

From ptjm@interlog.com (Patrick TJ McPhee)
Subject Re: Physical block structure in PostgreSQL
Date
Msg-id 4holu3Fik81U1@uni-berlin.de
Whole thread Raw
In response to Physical block structure in PostgreSQL  ("Spendius" <spendius@muchomail.com>)
List pgsql-general
In article <1152783428.682416.237320@p79g2000cwp.googlegroups.com>,
Spendius <spendius@muchomail.com> wrote:

% (I read the pages
% http://www.postgresql.org/docs/8.1/interactive/storage.html
% and saw things regarding files and "pages" that are "usually 8k"-big
% etc. but
% saw no further info about "blocks" - they speak of "items" here: what
% is it ?)

An item is the thing that's stored on the page. For instance, a database
table is stored in a bunch of pages in some file. Each row in the
table is stored as an item on a page, starting with a HeapTupleHeaderData.
The structure of an item for an index page might be different, though.

I found there was enough information in the section you cite to write a
simple data dumping tool in an emergency a while ago.
--

Patrick TJ McPhee
North York  Canada
ptjm@interlog.com

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