Re: Reorganizing the DB.. the tricky way

From: Rick Denoire <100.17706_at_germanynet.de>
Date: Sun, 06 Apr 2003 22:39:01 +0200
Message-ID: <e3319vg58ngj27fk8t4uaji6l94bh5av72@4ax.com>

"Anton Buijs" <aammbuijs_at_xs4all.nl> wrote:

>
>Fragmentation is probably caused (just guessing) because the initial setup
>was wrong choosen as we can judge it now, maybe it was ok at the moment the
>database was created. Now its up to Rick to take action and reorganize what
>has grown wrong in x years. Lucky we have "alter table move" available
>today.

One of the most popular "hobbies" of the developers is to add new column to existing tables and to populate these using update. Don't you think that - assuming the blocks have no more space free for the longer rows - this would cause ALL blocks to become migrated? In consequence, every input request for one record would cause 2 read operations, so making things 100% slower...

Don't know how to avoid this. One can't just set PCTFREE to 40% for every table, just in case one developer decides to add one column with large fields.

Bye
Rick Denoire Received on Sun Apr 06 2003 - 15:39:01 CDT