Re: changing the Seqence of the Columns in a Table

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Thu, 21 Mar 2002 10:42:33 -0000
Message-ID: <1016707468.2835.1.nnrp-07.9e984b29@news.demon.co.uk>

Rearranging column order to move frequently null columns to the end of the row can result in better data packing trailing nulls do not use any space. The benefit can be noticeable.

Putting frequently used, but unindexed, columns at the start of the row can save a small amount of CPU - particularly on large tablescans. The benefit is usually negligible though.

--
Jonathan Lewis
http://www.jlcomp.demon.co.uk

Next Seminar - UK, April 3rd - 5th
http://www.jlcomp.demon.co.uk/seminar.html

Host to The Co-Operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html

Author of:
Practical Oracle 8i: Building Efficient Databases


Michael Droste wrote in message <3c99256f$1_2_at_spamkiller.newsgroups.com>...


>Vladimir is right 'why you would want to reorder the columns?'

>

>Please tell us...

>

>

>

>--

>Posted via dBforums

>http://dbforums.com

Received on Thu Mar 21 2002 - 04:42:33 CST