Re: [SOLVED for good] performance tuning questions: replace IN (values) by JOIN

From: Howard J. Rogers <howardjr2000_at_yahoo.com.au>
Date: Mon, 1 Sep 2003 19:46:13 +1000
Message-ID: <3f5315cd$0$10359$afc38c87@news.optusnet.com.au>

"Jérôme Lacoste - CoffeeBreaks" <lacostej_at_coffebreaks.org> wrote in message news:RYC4b.18409

[snip]

>

> I saw that there was still a full table access on the BAG_LOG table, and
> now that I understand how thing works, I've added an index on the BAG_ID
> Foreign Key in the BAG_LOG table as it wasn't there. Strange as it was
> my understanding that Foreign Keys always have indexes on them in
Oracle...

Quite the opposite. Foreign keys nearly always *ought* to have indexes, but never do unless one makes it so. Terrible locking issues arise when non-indexed foreign keys are in place, and someone decides to update the parent table... Ugh!

Regards
HJR Received on Mon Sep 01 2003 - 04:46:13 CDT