Re: CLUSTER command
Jean-Luc Lachance <jllachan@nsd.ca>
From: Jean-Luc Lachance <jllachan@nsd.ca>
To: Stephan Szabo <sszabo@megazone23.bigpanda.com>
Cc: pgsql-general@postgresql.org, pgsql-performance@postgresql.org
Date: 2002-12-12T22:15:37Z
Lists: pgsql-performance, pgsql-general
The current cluster command is equivalant to: create b as select * from a order by i; So you would not be loosing anything. Stephan Szabo wrote: > > On Thu, 12 Dec 2002, Jean-Luc Lachance wrote: > > > Hi all, > > > > I just read about the cluster command and was a little (very) > > disapointed. > > Clustered tables do not remain clustered after inserts. > > Clustered tables are usefull when the table is very large and there are > > few different keys. > > > > > > Because the table file is already extended (2G limit) using different > > files extension (.N) > > how complicated (modifying the code) would it be to have the table files > > split according to the cluster key? > > I'd vote against changing the existing CLUSTER since the existing CLUSTER > while not great does handle many different key values fairly well as well > and this solution wouldn't. Many different key values are still > useful to cluster if you're doing searches over ranges since it lowers the > number of heap file reads necessary. If done this should probably be > separate from the existing cluster or at least both versions should be > possible.