As far as i can see my mail was not sent to list. I forward it:
---------- Forwarded message ----------
Date: Fri, 10 Dec 2004 05:15:42 +0200 (EET)
From: Ioannis Theoharis <theohari@calliope>
To: pgsql-general@postgresql.org
Subject: Clustering in the presence of hierarchies
I'd like to ask you about the clustering strategy that postgres
implements.
Exactly: I have created a hierachy of tables using 'inherits'
relationship. I have populated tables with a huge amount of data and then
I cluster each table according to an attribute that exists on Root table
(hence, this attribute is inherited by all tables).
In general, clustering for each of those table means to reorder on disc
tuples, in order to be sequential stored.
The question is:
Does postgres uses the knowledge of the hierarchy structure
to reorder tuples of each table to be stored almost after
its direct paent-table tuples?